[+/-] : Extraction of antimony trioxide from antimony sulfide ore

Disclosed is a process for extracting antimony trioxide from antimony sulfide ore concentrate by solubility differential of the trioxide in lower alkanol solutions of sodium or potassium hydroxide and wherein the total amount of water contained in the concentrate, the alkanol and the hydroxide is not more than 26.52 volume percent of the antimony sulfide content; which process includes treating the ore in the absence of substantial amounts of air with an alkanol solution containing an excess of sodium or potassium hydroxide, basis Sb.sub.2 S.sub.3 content in the ore; separating also, in the absence of substantial amounts of air, insoluble concentrate material from a filtrate composed of water, alkanol, hydroxide and sulfide of potassium or sodium, antimony trioxide trihydrate, sodium or potassium dihydro pyroantimonite; repeatedly extracting the insoluble material with the filtrate also in the absence of substantial amounts of air; allowing the filtrate to settle so as to form a precipitate of antimony trioxide and sodium or potassium dihydro pyroantimonite; separating the precipitate from the filtrate; dehydrating the precipitate to leave behind a mixture of antimony trioxide and hydroxide of sodium or potassium; and adding the separated alkanol to the mixture to dissolve the hydroxide and leave behind antimony trioxide.

BACKGROUND OF THE INVENTION

This invention relates to a novel process for recovering antimony trioxide from antimony sulfide ores and concentrates.

The main object of this invention is to reduce the air, water, thermal and chemical pollution inherent in present processes of making antimony trioxide.

No heat or pressure is used in the disclosed process itself and any reduced pressure or heat is used only in recycling of the alcohol and sodium or potassium hydroxide reagents.

The process is remarkably efficient in recovering antimony trioxide from antimony sulfide concentrates.

By excluding atmospheric oxygen and by the use of closed and preferably full containers and filters and with the removal of excess sulfur through decomposition of the antimony pentasulfide at temperatures above 75.degree. C, it is possible to maintain antimony in a tri-valent state of oxidation wherein no thio-antimonates are formed. Antimony, in this tri-valent state, forms little thio-antimonites, which tend to decompose to antimony tri-sulfide.

Use of the solubility differential between antimony trioxide and antimony tri-sulfide in various alcohol solutions, coupled with the addition of sodium or potassium hydroxide to the alcohol solution, coupled with the inability of antimony to form a hydroxide produces an unpredictable reaction wherein antimony trioxide is the end product.

Antimony trioxide finds utility in the manufacture of tartar emetic; as a paint pigment; in enamels and glasses; as a mordant; and in flame proofing.

The reaction of the process according to the present invention is as follows:

Sb.sub.2 S.sub.3 + 6 KOH or 6 NaOH in an ethanol, methanol or other alcohol solution, (wherein the concentration is approximately 16.66% solution of KOH, or 8% solution of NaOH) = 3 K.sub.2 S or 3 Na.sub.2 S + Sb.sub.2 O.sub.3.3H.sub.2 O. The sodium sulfide (mono) is only slightly soluble in ethanol or mehanol whereas the potassium sulfide is much more soluble.

In addition to the water of hydration formed during the initial reaction, water is found as an impurity in the antimony sulfide concentrate in the sodium or potassium reagents and in the alcohol reagents, 15.92% of the weight of Sb.sub.2 S.sub.3 in the concentrate will be water. The upper limit of the water content is 26.52%. In the presence of this quantity of water, the following reactions occur:

2 H.sub.3 SbO.sub.3 (antimonous acid -- a representation of trihydrated antimony trioxide) + 2 NaOH or 2 KOH + 2 H.sub.2 O = Na.sub.2 (or K.sub.2) H.sub.2 Sb.sub.2 O.sub.5.5H.sub.2 O. This is the sodium or potassium dihydro pyro-antimonite. Various other derivations of a compound of the same empirical formula exist through the sodium or potassium hydroxyantimonite and sodium or potassium meta-antimonite.

2( (Na) or (K) Sb (OH).sub.4.H.sub.2 O) = Na.sub.2 (or K.sub.2) H.sub.2 Sb.sub.2 O.sub.5.5H.sub.2 O

2( (na) or (K) SbO.sub.2.3H.sub.2 O) = Na.sub.2 (or K.sub.2) H.sub.2 Sb.sub.2 O.sub.5.5H.sub.2 O

after mixing the antimony sulfide concentrate and the alcohol solution of sodium or potassium hydroxide and with an agitation supplied from 1 to 3 minutes at temperatures not exceeding 65.degree. F the mixture is filtered. It is best to use full closed containers for the mixing and the filtration should be with limited access to atmospheric oxygen. This is to prevent any oxidation of antimony from the tri-valent state to the pentavalent state of oxidation. Filtration should be accompanied by agitation of the material to prevent caking on the sides and thus trapping some of the white precipitate material in the solid residues.

Some of the finely divided white precipitate of antimony trioxide or antimony-potassium - oxygen hydrated compounds will pass a No. 4, 1 or 2 filter paper. The bulk of the formation of these white precipitates occurs in the filtrate after it has passed the filter paper. This is due to the fact that sodium or potassium meta-antimonite is unstable in water and the remainder is due to the pairing of sodium or potassium hydroxy antimonite molecules when sufficient water is available for their hydration to permit the formation of the compound empirically written as sodium or potassium di-hydro pyro-antimonite. This compound is quite insoluble as the sodium compound and more soluble as the potassium compound, and seems to be the principal precipitate formed in the filtrate. The amount of water necessary to form this compound is an additional 66.66% of the total amount of water formed in the initial reaction.

The total time for precipitation from the filtrate is up to four hours. This time can be reduced by the addition of sufficient water to permit the required degree of hydration to occur. The ratios are:

______________________________________
Sb.sub.2 S.sub.3 + 6 KOH or 6 NaOH = 3 (K.sub.2 S) or 3 Na.sub.2 S +
Sb.sub.2 O.sub.3 .multidot.3H.sub.2 O
339336240330234345
followed by:
Sb.sub.2 O.sub.3 .multidot.3H.sub.2 O expressed as 2 (H.sub.3 SbO.sub.3)
+ 2 H.sub.2 O + 2 NaOH or
3453453680
2 KOH = Na.sub.2 (or K.sub.2) H.sub.2 SbO.sub.5 .multidot.5H.sub.2 O.
112(493 for K)(461 for Na)
______________________________________



The total amount of water required as 90 parts of water with the varius ratios to the other ingredients of the mixture (54 of the 90 is produced in the initial reaction).

There is also the hydrolysis of the potassium sulfides and sodium sulfides produced in the reaction:

K.sub.2 S + H.sub.2 O = KHS + KOH and Na.sub.2 S + H.sub.2 O = NaHS + NaOH

hydrolysis of the sodium or potassium sulfides occurs because the ratio of 6 KOH or 6NaOH is sufficient with 1 mole of Sb.sub.2 S.sub.3 to complete the reaction all the way to the sodium or potassium di-hydro pyro-antimonite--if there were no hydrolysis the number of sodium and potassium hydroxides in the equation would be 8. With sodium, the insolubility of the mono-sulfide in the alcohols requires a greater than 6 ratio, preferably 8. Potassium did not require a greater ratio than 6.

When formed 3 - 5 minutes have elapsed, the filtrate with the white precipitate forming in it can be centrifuged and the solids removed. The clear filtrate is then added to the residues in the filter paper and additional extractions can be made which will continue to precipitate in the filtrate after passing the filter paper. An extraction of 97% of the antimony can be made by recycling the proper amount of filtrate a fifth time. As little exposure to atmospheric oxygen as possible should be allowed in both the mixing the filtering and the re-addition of the clarified filtrate to the solid residues.

When the re-use of the clarified filtrate is ended, the solids are removed from the filtrate--as much as 4 hours may be required to completely precipitate the white substances. If the procedures are properly carried out there are no yellow formations on the filter paper from formation of thio-stibnates nor are there any red-yellow-brown residues from the decomposition of sodium or potassium thio-stibnite into antimony tri-sulfide. When the white precipitate is removed, either reduced pressure or application of heat can be used to distill the alcohol from the water solution of sodium or potassium hydroxide (the excess), the sodium or potassium sulfides and their hydrolyzed products formed in the reaction, and the arsenic sulfides and oxides (both of which are soluble in ethanol-methanol). The methanol can be distilled at 15.degree. C under 73mm of Hg pressure. The reduced pressure and applied heat should be such that the alcohol will distill but leave the water behind.

With the removal of the alcohol, the arsenic can be precipitated with a water soluble calcium salt as an insoluble calcium thioarsenite, or calcium arsenite.

The remaining water solution will contain mainly sodium or potassium hydroxide and sodium or potassium hydro-sulfide or polysulfides. The potassium compound is readily decomposed into hydrogen sulfide gas at or near the boiling point of water. The sodium equivalent requires steam at 140.degree. C to reach the same rate of decomposition.

The produced hydrogen sulfide can be burned to produce some or all of the energy required in the process. The burning of hydrogen sulfide in a limited supply of oxygen results in the formation of water and elemental sulfur.

The hydrogen sulfide can be decomposed into elemental hydrogen and sulfur at temperatures beginning at 310.degree. C. This hydrogen can then be used to replace antimony from antimony compounds which are water soluble thereby recovering elemental antimony.

The white precipitate is dried and dehydrated thermally. The temperatures employed are up to 235.degree. C. When the water has been driven off sodium or potassium hydroxide remains with antimony tri-oxide. Addition of the re-cycled and distilled ethanol or methanol to the dehydrated compound will allow the sodium or potassium to re-enter solution for use in treating additional antimony sulfide concentrate and leave the insoluble antimony tri-oxide as the product.

Antimony pentasulfide is not a naturally occurring substance. If it is present in the concentrate, heating the concentrate to 75.degree. C or higher, will reduce this pentasulfide to the tri-sulfide and elemental sulfur. It is necessary to remove this sulfur by gravity or other means (such as carbon disulfide) as either this excess free sulfur or the pentasulfide can react with the sodium or potassium sulfides produced in the reaction and form undesirable sodium or potassium thio-antimonates.

Before addition of water to the process, the total water content of the concentrate, the sodium or potassium reagents and of the alcohol should be considered. Generally, there is sufficient water available from these sources for the process. The amount of water should not exceed 10.61% of the weight of the Sb.sub.2 S.sub.3 of the concentrate.

The following examples illustrate but do not limit the invention. All the parts given are by weight unless volumes are specified.

EXAMPLE I

100 grams of potassium hydroxide was dissolved in sufficient methanol to make a total volume of 300cc or 33.3%. The solution was allowed to cool to 50.degree. F before using. The solution was made in a stoppered 500cc flask.

The antimony sulfide concentrate contained 60% antimony or 83.7% antimony sulfide. The potassium hydroxide was 90% pure. After these corrections for antimony tri-sulfide content of the concentrate and the corrections for purity for the potassium hydroxide at a ratio of 1 Sb.sub.2 S.sub.3 to 6 KOH, the figures are 100 grams of KOH and 109.5 grams of 60% antimony content concentrate. The concentrate was heated to 229.degree. C for 1 hour. Instead of a gravity separation or a solvent for the sulfur produced in the decomposition of the antimony pentasulfide present, the excess sulfur was burned off as sulfur dioxide. This sulfur dioxide was reacted with hydrogen sulfide gas and approximately 1/2 gram of sulfur was recovered.

When both the concentrate and the methanol solution of KOH were at 50.degree. F, they were mixed in the 500cc flask. The flask was kept stoppered during the three minute shaking of the flask. The contents of the flask were poured into a large six inch funnel mounted in a rubber stopper into another 500cc flask. The funnel surface was covered with poly-ethylene wrap to exclude oxygen. The flask holding the funnel was swirled to keep the solids from caking the sides of the No. 4 filter paper.

The filtrate was largely clear at first and then the white precipitate began to form. When about one-half the contents of the filter paper had filtered through (3 minutes in time), the filtrate was removed from the flask and centrifuged in stoppered tubes. The solids were retained and the mostly clear filtrate was added to the filter paper solid residues along with the portion of the liquids that had not yet passed the filter paper. This procedure (adding the filtrate back to the filter paper residues) was repeated five times. The contents of the filter paper were allowed to completely pass as filtrate into the collecting flask. Little discoloration of the filter paper occurred.

Calcium chloride (2 grams) was added to the filtrate after the filtrate had been allowed to stand for 4 hours and the white precipitate removed by centrifuging. The arsenic content was so low in this concentrate that no visible precipitate was formed. The methanol was distilled off at 70.degree. C under 26mm of Hg pressure leaving a red-yellow and yellow brown solid. This solid corresponded according to melting points to potassium sulfide and potassium di-sulfide. After checking melting points (470.degree. C) this substance was added to water and the water boiled. The hydrogen sulfide that formed was led by the vapor pressure of the boiling solution into a flask of KOH. The solution was boiled for 1 hour and no further odor of hydrogen sulfide was noted. Zinc sulfate solution was titrated with the hydrogen sulfide dissolved in the KOH solution. 15.84 grams of sulfur were calculated to have precipitated as zinc sulfide. This corresponded to 58.43% of the sulfur present in the original 109.5 grams sample of antimony sulfide concentrate (before the break-down of the pentasulfide and the removal of this sulfur by thermal means). The recovery of antimony was at 36.6 grams corresponding to a 61% recovery of a 60% antimony content of the concentrate. The white precipitate was dried and then heated to 200.degree. C to drive off the water of hydration. The antimony content of the final oxide after the removal of the reconstituted potassium hydroxide by the distilled methanol was 83.2% of the total solid residues. No sulfur could be found by analysis in this residue. This product therefore corresponded to over 99% pure Sb.sub.2 O.sub.3. An excess of potassium hydroxide in a more dilute form was used in Example 2. 150 grams of potassium hydroxide were made up to 600 cc in an Erlenmeyer flask which was stoppered. The solution strength in Example 1 was 33.3% and in this example was 25%. Methanol was the solvent.

The same quantity of the same 60% antimony content concentrate (109.5 grams) was treated with the potassium hydroxide in methanol solution when the temperature was 50.degree. F.

Example 2 was not heated to over 75.degree. C to remove and decompose the antimony pentasulfide present in the concentrate. The antimony sulfide concentrate was added to the KOH methanol solution and shaken for 3 minutes. The contents of the flask were then added to a funnel containing a filter paper and above the filter paper was placed a watch glass. The time lost in removing the polyethylene wrap probably allowed more exposure to oxygen than did the use of the watch glass. The funnel was placed in the stopper of another 1000 cc flask. This flask had a bottom outlet fitted with tubing and a clamp. When the filtrate reached 200cc, the filtrate was drained off through the bottom outlet into stoppered centrifuge tubes. Centrifuging removed the white precipitate which had already formed in the first 3 minutes of filtration. The clear filtrate was readded to the funnel filter paper solids. The filter paper solids remained a darker color than did those of Example 1. By not pre-heating the concentrate some light yellow staining appeared at the top of the filter paper indicating the formation of potassium thio-antimonate. The residues were treated with the clear filtrate five times.

In this Example, the end product contained 83% of the antimony present in the 109.5 grams sample and the purity was 99+ % antimony tri-oxide, i.e., of the 65.7 grams of antimony in the original 109.5 gram sample 54.53 grams were recovered. The end product contained no sulfur that could be detected (0.1% is the limit of detection). The end product after methanol extraction of the de-hydrated antimony-potassium-oxygen compound gave a percentage of over 83% antimony.

EXAMPLE 3

A raw ore (not a concentrate) containing 41% antimony as antimony sulfide was treated with a more dilute solution of potassium hydroxide in methanol. 50 grams of potassium hydroxide was made up to 300cc total volume with methanol. This ore contained mostly a silicate base and 2.6% arsenic.

This ore was pulverized to - 90 mesh. The 50 grams of ore contained 20.5 grams of antimony and 8.1 grams of sulfur in the antimony tri-sulfide. The total weight of antimony tri-sulfide was 28.6 grams. The potassium-methanol extraction of this ore gave a 93% recovery of the antimony in five washes with the clear filtrate after the precipitated white solids removed. Nineteen grams of antimony were recovered in a substance (the dehydrated white precipitate after using methanol to dissolve the potassium hydroxide) and the percentage of antimony in the oxide was over 83%, indicating that antimony tri-oxide had been formed.

EXAMPLE 4

The above experiment was repeated with 50 grams of KOH made up to 500cc of methanol and used to treat 35 grams of 60% antimony content antimony sulfide concentrate. With five washes of the filter solids with the filtrate after removal of the white precipitate, a 97% recovery of the antimony was achieved with a antimony content of the final oxide of over 83%. The material was left in the closed bottle with the potassium hydroxide excess and the potassium sulfide that had formed for 3 weeks and did not react to discolor the white precipitate.

EXAMPLE 5

Twenty grams of sodium hydroxide were made up to 250cc ethanol with heat. When the solution had cooled to 50.degree. F it was mixed with 34 grams of 60% antimony content (antimony sulfide) in a 500cc stoppered flask. After 3 minutes, the solution was filtered. (Less care for the exclusion of oxygen was made with the sodium. No watch glass cover, etc., were used.) As the white precipitate formed in the filtrate, it was removed and the clear filtrate added to the filter paper with its solid residues and liquids which had not yet passed the filter paper. An additional 20 grams of sodium hydroxide in 250 cc of ethanol was added to this filter paper and used along with the re-cycled clear filtrate. This gave a product (white precipitate which took longer to form) containing over 83% antimony. The recovery was approximately 95 to 96% of antimony recovered from that in the original sample. This sodium product was allowed to stand eight days in an unstoppered bottle and the clear portion of the filtrate turned yellowish but the solids remained white.

Alkanol Solubility Considerations and Reuse

Potassium hydroxide when made up as a saturated solution in water is immiscible with ethanol.

Potassium hydroxide when made up as a saturated solution in water is miscible with methanol.

Sodium hydroxide when made up as a saturated solution in water is miscible with both ethanol and methanol.

Potassium sulfides and polysulfides can be extracted from an ethanol solution by adding drops of water to the ethanol solution. The ethanol solution will become colorless, while the small amount of water dropped through the ethanol solution will become reddish and will remain immiscible with the ethanol. An excess of water will cause the water and the ethanol to mix and separation is no longer possible. Methanol does not separate into two layers.

Ethanol is the preferred alkanol because it is not necessary to distill it from solution by proceeding as follows: The potassium sulfides and polysulfides are removed by the small amount of water added (drop by drop) to the ethanol solution. This addition of water is made after the original filtration. It is in the filtrate that the bulk of the potassium meta-antimonite, potassium hydroxy antimonite and potassium di-hydro pyroantimonite is formed. This material is removed in a second filtering or by centrifuging. After this, the water can be added to remove the potassium sulfide or polysulfides in an immiscible (with ethanol) water solution. This water solution is heavier than the ethanol solutions and will collect at the bottom of the vessel and can be withdrawn. This solution becomes colored as the ethanol loses whatever coloration it has and an easy visual separation is possible. When at the next step a soluble salt of calcium or some other metal (to form insoluble arsenites) is used to precipitate the ethanol soluble arsenic oxides or any unreacted sulfides; the ethanol is ready for reuse in the process.

The potassium sulfides and polysulfides extracted in the immiscible water layer are readily decomposed into hydrogen sulfide gas and potassium hydroxide from a water solution at 100.degree. C. The hydrogen sulfide can be burned in limited oxygen and may produce elemental sulfur and water and sufficient energy for the entire process.

The potassium hydroxide is much more soluble in ethanol than is sodium hydroxide. An ethanol solution containing 14.28% potassium hydroxide can be used. The practical limits of the sodium hydroxide solution in ethanol is about 8%.

To clean a used ethanol solution of K.sub.2 S and KOH, pure water is added in very small quantities. The differential solubility between a water solution of potassium sulfides and an ethanol solution of potassium sulfides is such that the potassium sulfides will pass from the ethanol solution into the water solution. When sufficient ions are present in the ethanol solution of potassium hydroxide (a concentrated ethanol solution at nearly the saturation point) these ions (soluble in both ethanol and water) will tend to push the potassium sulfide ions into the water, due to the much greater solubility in water than in ethanol of the potassium sulfide. The ethanol solution is not completely cleaned of the potassium sulfide but the potassium sulfide content is greatly reduced. When water is saturated with either potassium sulfide or with potassium hydroxide it will not mix with ethanol. When very little water is added to the ethanol solution (containing potassium hydroxide to react with the antimony tri-sulfide) and also containing the potassium sulfide formed in the reaction with the antimony tri-sulfide, the greater water solubility of potassium sulfide will permit it to pass into the water from the ethanol.

If sufficient water is added so that the ethanol and water solutions mix, the separation is ruined and cannot be reconstituted. The reasons for this is molecular particle size. When 100cc of ethanol and 100cc of water are mixed the resulting quantity is 170cc not 200cc. The molecules are interspersed in these miscible liquids. Potassium being a large ion, its density is the least of any metal except lithium. The potassium ion when (as a sulfide or a hydroxide) dissolved in water to a point of saturation will align the water dipoles in an even larger configuration. The potassium sulfide or hydroxide ions so arrayed with the water dipoles have such a size that molecules of ethanol cannot intersperse between (saturated) KOH or K.sub.2 S ions arrayed with the dipoles. Sodium is smaller and ethanol can enter even a saturated NaOH - water solution and therefore the solutions are miscible. Smaller alcohol molecules (methanol) can intersperse the KOH or K.sub.2 S saturated water solution and the solutions become miscible. For this reason, the larger alcohols butanol, propanol, etc., probably could even prevent miscibility with both potassium and sodium compounds.

In the present process, the cleaning of the ethanol solution reversed the process, by having the ethanol contain both the KOH and K.sub.2 S. A very small quantity of water will pick up the K ions and mainly the S ions which will form a saturated water solution from the acquisition of these ions from the ethanol. In this saturated form the water is immiscible with ethanol. This gives a cleaning to the ethanol by removing most of the K sulfides. If the solution (water) is less than saturated the two solutions mix and cannot again be separated. It is much easier to drop a little water through the ethanol than to boil all the ethanol to dryness to recover the K sulfides. To insure the immiscibility of two liquids when potassium hydroxide is used dissolved in ethanol, propanol or butanol, the potassium sulfide formed in the reaction with antimony sulfide preferably is removed with a saturated water solution of potassium hydroxide. A saturated KOH solution is immiscible with ethanol. The potassium sulfide will dissolve in the water solution of KOH, and some KOH is displaced and forms new reagent when it is displaced into the ethanol. The removal of the potassium sulfide from the ethanol solution will be at the same rate that the saturated water solution of KOH releases KOH into the ethanol. The presence of saturated KOH decreases the posibilities of the water solution of KOH and K.sub.2 S becoming miscible with the ethanol solution of KOH.

This is effective in the case of potassium hydroxide (not sodium hydroxide) in ethanol (not in methanol) and two immiscible layers are formed (water and ethanol).

For over 2% antimony sulfide content concentrates a 5 to 50% addition of carbon disulfide to the alkanol solution of sodium or potassium hydroxide will greatly increase the solubility of antimony sulfide in this carbon-disulfide-alkanol-sodium or potassium hydroxide solution.

The antimony sulfides are very much more soluble in CS.sub.2 than in alkanols. CS.sub.2 is miscible with the alkanols. The solution of the sodium or potassium hydroxides in the alkanols is mixed with CS.sub.2 in proportions of from 5% CS.sub.2 : 95% alkanol solution to 50% CS.sub.2 alkanol solution. This ratio is by volume.




Sam Xu
Sales Engineer

DONGGUAN JIEFU FLAME-RETARDED MATERIALS CO.,LTD
Address: jiefu industrial park shuiping industrail district dalang town dongguan GD,P.R.C
Zip: 528770
Tel: 0086-755-83474911
FAX: 0086-755-83474980
Mobile:13929211059
Contact me: xubiao_1996@hotmail.com samjiefu@gmail.com

Jiefu Chemical industry LTD . (Our imports and exports company )

Chinese antimony market



DONGGUAN JIEFU FLAME-RETARDED MATERIALS CO.,LTD...
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[+/-] : Process for producing antimony trioxide

Abstract:
A process for the production of antimony trioxide comprising the steps of: (i) reacting antimony trisulfide with iron (III) chloride to produce antimony trichloride; and (ii) hydrolyzing antimony trichloride to produce antimony trioxide. In a preferred embodiment, the process is substantially closed or near-closed loop. Antimony trioxide is a known flame retardant for use in plastics, ceramics and the like.

Description:
BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a process for the production of antimony trioxide.

2. Description of the Prior Art

Antimony trioxide, also known as antimonous oxide and/or Sb.sub.2 O.sub.3, is a known compound useful in the manufacture of paints, plastics, ceramics, and the like. The principal utility of antimony trioxide is as a flame retardant.

Conventionally, antimony trioxide is produced by high temperature roasting/smelting processes using antimony trisulfide concentrate as the starting material. Antimony trisulfide concentrate contains large amounts (e.g. >80% by weight) of antimony trisulfide. The following is the principal reaction that occurs during conventional roasting/smelting:

2Sb.sub.2 S.sub.3 +9O.sub.2 .fwdarw.2Sb.sub.2 O.sub.3 +6SO.sub.2 .uparw.

One of the principal concerns in conventional production of antimony trioxide is the concurrent production of SO.sub.2. Specifically, unabated release of this sulfur dioxide is known to lead to acid production which has significant detrimental effects on the environment. Thus, it is necessary to scrub sulfur dioxide emissions (for example by flue gas desulfurization technology) produced during manufacture of antimony trioxide. In a typical commercial plant using this conventional technology for production of antimony trioxide, the capital cost of scrubbing sulfur dioxide emissions can approach or even exceed two orders of magnitude more than the capital cost of the process which produces antimony trioxide.

Thus, not surprisingly, the capital cost of a commercially viable conventional roasting/smelting process can be in excess of CDN$20 million. Further, conventional roasting/smelting processes lack the flexibility to produce alternate crystalline forms of antimony trioxide (i.e. senarmontite or valentinite) or to vary the particle size distribution of the product.

Recent attempts to solve these problems include: (i) a high temperature chlorination coupled with calcium chloride reactant (Bureau de Recherches Geologiques et Minieres in Orleans, France), and (ii) high temperature chlorination coupled with hydrochloric acid reactant (Preussag GB Erdol und Chemie). Approach (i) is deficient since the need to conduct the reaction at approximately 500.degree. C. results in a very corrosive reaction system necessitating the use of reactors made of specialized titanium alloys--this dramatically increases the capital and process maintenance costs of the plant. Approach (ii) is deficient since sulfur from the starting material is converted to hydrogen sulfide (H.sub.2 S) which must be scrubbed or otherwise treated to obviate or mitigate a negative impact on the environment--this also dramatically increases the capital and process maintenance costs of the plant.

Thus, while the commercial demand for antimony trioxide remains high, there is little room in an environmentally conscious world for a conventional roasting/smelting process which converts antimony trisulfide to antimony trioxide. Further, the recent attempts at improved technologies have met with little or no commercial success.

Accordingly, the art is in need of a process for production of antimony trioxide which avoids the problems of the prior art.

It would be desirable to have an improved process for production of antimony trioxide. Ideally, the improved process: (i) could be implemented at relatively low capital cost, (ii) would avoid the production of environmentally hazardous compounds such as SO.sub.2 and H.sub.2 S, (iii) could be conducted at or near the source of antimony trisulfide, and/or (iv) would minimize the need for large quantities of virgin reagents (i.e. reagents used in the improved process could be readily recycled to provide a closed or near-closed loop reaction system).

SUMMARY OF THE INVENTION

It is an object of the present invention to obviate or mitigate at least one of the above-identified disadvantages of the prior art.

Accordingly, the present invention provides a process for the production of antimony trioxide comprising the steps of:

(i) reacting antimony trisulfide with iron (III) chloride to produce antimony trichloride; and

(ii) hydrolyzing antimony trichloride to produce antimony trioxide.

Thus, in the present process antimony trisulfide is reacted with iron (III) chloride to produce an antimony trichloride intermediate which can be readily converted to antimony trioxide. The present process is ideally suited to utilize antimony trisulfide concentrate as a starting material. As is known in the art, antimony trisulfide concentrates may be produced by flotation techniques to produce a concentrate material which contains at least about 70% by weight, preferably at least about 90% by weight, antimony trisulfide. The remainder of the concentrate comprises silica and heavy metal impurities.

As will be described in more detail hereinbelow, a key advantage of the present process is that the production of environmentally hazardous by-products (i.e. materials which can not be recovered and must be treated (at large capital cost) prior to emission) is avoided. Thus, in the present process the by-products of each reaction and/or treatment step may be recycled and reused without emission into the environment. The result of this is that the present process is a closed or near-closed loop system which does not require large amounts of virgin bulk reagents. Solid by-products produced (e.g. silica, trace amounts of heavy metal and the like) may be disposed of relatively easily. This is a highly advantageous feature of the present process since it obviates or mitigates shipment of large quantities of reagents and other materials needed for the process thereby facilitating commercial implementation of the process in remote locations.

The present process does not require the use of capital cost intensive scrubbers and other capital cost intensive by-product treatment technologies. Thus, the present process may be implemented on a commercial scale at relatively low capital cost compared with a commercially viable conventional roasting/smelting plant incorporating scrubbers to dealing with sulfur dioxide emissions.

Further, the ability to implement the present process at relatively low temperatures and substantially ambient pressure serves to enable a reduction in relative overall costs associated with operation of the present process on a commercial scale.

BRIEF DESCRIPTION OF THE DRAWING

Embodiments of the present invention will be described with reference to the accompanying FIGURE which is a schematic of an embodiment of the present process.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the accompanying FIGURE, there is illustrated a holding tank A which serves to hold a supply of antimony trisulfide concentrate. Holding tank A is connected to a leach station B via a line 10. Leach station B is connected to a solvent extraction station C via a line 15. Solvent extraction station C is connected to leach station B via a line 85. Solvent extraction station C is connected to a hydrolysis station D via a line 20. Hydrolysis station D is connected to a dewatering/drying station E via a line 25.

A line 30 connects a chlorination station F to leach station B. Solvent extraction station C is connected to chlorination station F via a line 35. A line 40 connects dewatering/drying station E to solvent extraction station C.

A line 45 connects line 40 to an ammonium recovery station G. Ammonium recovery station G is connected to a brine purification station H via a line 50. Brine purification station H is connected to a chloro-alkali electrolysis station I via a line 55.

A line 60 connects chloro-alkali electrolysis station I to chlorination station F. A line 65 connects chloro-alkali electrolysis station I to ammonium recovery station G. A line 80 connects chloro-alkali electrolysis station I to line 40. A line 90 connects line 80 to solvent extraction station C. A line 70 connects line 65 to brine purification station H.

In the context of the illustrated embodiment, the present process can be operated in the following manner.

Antimony trisulfide is metered from holding tank A to leach station B via line 10. Iron (III) chloride is fed from chlorination station F to leach station B via line 30. The operation of chlorination station F will be described in more detail hereinbelow.

While not wishing to be bound by any particular theory or mode of action, it is believed that, in leach station B, antimony trisulfide and iron (III) chloride react overall in the following manner:

6FeCl.sub.3 +Sb.sub.2 S.sub.3 .fwdarw.2SbCl.sub.3 +6FeCl.sub.2 +3S

Thus, during the reaction, iron (III) chloride is reduced to iron (II) chloride. The antimony trichloride and iron (II) chloride generally remain in solution.

Preferably, the iron (III) chloride is used as an aqueous solution. While the source of iron (III) chloride is illustrated as chlorination station F, those of skill in the art will realize that an initial source of iron (III) chloride will be used. Preferably, the initial source of iron (III) chloride is an aqueous solution. Preferably, such an aqueous solution comprises from about 5% to about 15%, more preferably from about 8% to about 13%, most preferably from about 10% to about 12%, by weight iron (III). As is known in the, in order to dissolve these quantities of iron (III) in water, it is generally necessary to acidify the aqueous solution. For reasons which will become apparent hereinbelow, a preferred acid for this purpose is hydrochloric acid. Preferably, the hydrochloric acid has a concentration in the range of from about 0.05 to about 4.0, more preferably from about 0.1 to about 1, most preferably from about 0.1 to about 0.5, percent by weight.

Conveniently, the initial source of iron (III) chloride for use in the present process may be a waste stream from another industrial process. For example, a preferred initial source of iron (III) chloride for use in the present process is an iron containing waste stream from pickle liquor used in conventional steel manufacturing plants.

Preferably, the antimony trisulfide and the iron (III) chloride are contacted in leach station B at a temperature in the range of from about 50.degree. to about 100.degree. C., more preferably from about 60.degree. to about 90.degree. C., most preferably from about 75.degree. to about 85.degree. C.

Preferably, the antimony trisulfide and the iron (III) chloride are contacted in leach station B for a period of from about 10 to about 60 minutes, more preferably from about 25 to about 50 minutes, most preferably from about 30 to about 40 minutes.

To facilitate reaction of the antimony trisulfide and the iron (III) chloride, it is preferred to agitate the two. This can be accomplished using conventional mechanical mixers (e.g. rotary impellers) and the like.

In the present process, it is desirable that the antimony chloride-containing liquid emanating from leach station B via line 15 be substantially free of iron (III) chloride. The reason for this will be explained in more detail hereinbelow.

Thus, in a preferred embodiment, leach station B is divided into at least two stages (not shown). In the first stage, antimony trisulfide is reacted with less than a stoichiometric amount of iron (III) chloride. Preferably, the first stage comprises reacting antimony trisulfide with from about 60% to about 95%, more preferably from about 70% to about 90%, most preferably from about 75% to about 85%, of a stoichiometric amount of iron (III) chloride.

The advantage of this approach is that, in the first stage, since iron (III) chloride is present in a sub-stoichiometric amount, it substantially completely reacts with the antimony trisulfide which is present in excess in the first stage. The resulting reaction mixture comprises antimony trichloride and iron (II) chloride in solution, and unreacted antimony trisulfide and sulfur (a by-product of the reaction--see above) particles in suspension. The unreacted antimony trisulfide and sulfur particles may be separated from the reaction mixture using any conventional physical separation technique. The separated liquid (i.e. containing antimony trichloride and iron (II) chloride in solution) is then fed to solvent extraction station C via line 15.

The unreacted antimony trisulfide and sulfur particles from the first stage of leach station B are preferably then reacted in a second stage of leach station B. Preferably, the second stage of leach station B comprises reacting the antimony trisulfide particles from the first stage of leach station B with at least a substantially stoichiometric, preferably an excess stoichiometric, amount of iron (III) chloride. Thus, the reaction mixture produced in the second stage of leach station B comprises antimony trichloride, iron (II) chloride and iron (III) chloride in solution, and sulfur particles and other insoluble impurities in suspension. The sulfur particles and other insoluble impurities may be separated from the reaction mixture using any conventional physical separation technique and are fed to a waste disposal station (not shown) via a line 33. The separated liquid (i.e. containing antimony trichloride, iron (II) chloride and iron (III) chloride in solution) is then fed to the first stage of leach station B.

Thus, as will be appreciated by those of skill in the art, the product of leach station B is an aqueous liquid comprising antimony trichloride and iron (II) chloride in solution. The aqueous liquid comprising antimony trichloride and iron (II) in solution is fed to solvent extraction station C via line 15. As discussed above, it is preferred that the aqueous liquid fed to solvent extraction station C is the result of reaction of antimony trisulfide with a sub-stoichiometric amount of iron (III) chloride (e.g. from the first stage of leach station B discussed hereinabove).

In solvent extraction station C, the aqueous liquid comprising dissolved antimony trichloride and iron (II) chloride from leach station B is contacted with an organic solvent resulting in extraction of antimony trichloride from the aqueous liquid to the organic solvent. Ideally, the organic solvent for use in solvent extraction station C should be one which acts to complex one of antimony trichloride or iron (II) chloride to the exclusion of the other. In the context of the present process, it has been discovered that an organic solvent comprising tributyl phosphate is particularly well suited for this purpose. Specifically, when contacted with a mixture comprising both antimony trichloride and iron (II) chloride, tributyl phosphate will selectively complex with antimony trichloride.

Preferably, the organic solvent for use in organic solvent extraction station C comprises tributyl phosphate in an amount in the range of from about 20% to about 70%, more preferably from about 20% to about 60%, most preferably from about 20% to about 35%, by volume of the organic solvent. The remainder of the organic solvent may be any organic liquid which is miscible with and does not deleteriously affect the function of the organic solvent in solvent extraction station C. Preferably, the remainder of the organic solvent is kerosene.

To facilitate extraction of the antimony trichloride from the aqueous liquid into the organic solvent, it is preferred to agitate the two. This can be accomplished using conventional mechanical mixers (e.g. a rotary impeller) and the like.

Although not wishing to be bound by any particular theory or mode of action, it is believed that the following overall reaction occurs in solvent extraction station C:

SbCl.sub.3 +n(C.sub.4 H.sub.9).sub.3 PO.sub.4 .revreaction.SbCl.sub.3.((C.sub.4 H.sub.9 O).sub.3 PO).sub.n

The antimony-organic complex believed to result from the reaction is readily soluble in the organic solvent in solvent extraction station C. The iron (II) chloride is minimally affected by contact with the tributyl phosphate and thus a majority remains in the aqueous solvent.

As described above, it is desirable in the present process to avoid the presence of iron (III) chloride from leach station B in solvent extraction station C. The principal reason for this is that the preferred extraction solvent comprising tributyl phosphate will not differentiate between antimony trichloride and iron (III) chloride. The result of this would defeat the purpose of solvent extraction station C, namely to separate substantially all of the antimony trichloride from the aqueous liquid from leach station B. This potential problem is mitigated or obviated by using the preferred two-stage design of leach station B discussed hereinabove.

Upon completion of extraction, the organic solvent (comprising dissolved antimony trichloride believed to be in the form of the antimony-organic complex referred to hereinabove) and the aqueous liquid are separated using conventional techniques such as phase separation and the like.

While the solvent extraction station C as described is effective for selective extraction of antimony trichloride, in certain cases trace amounts of iron (II) compounds may be concurrently extracted into the organic solvent. In such cases, after separation of the organic solvent from the aqueous liquid in solvent extraction C, it is preferred to scrub the organic solvent with an aqueous solvent which will selectively remove any trace amounts of iron (II) compounds present in the organic solvent. Preferably, the aqueous solvent used to scrub the organic solvent is an aqueous inorganic acid. In the context of the present process, aqueous hydrochloric acid has been found to be particularly useful to scrub the organic solvent and remove any trace amounts of iron (II) compounds which may be present in the organic solvent. Preferably, the aqueous inorganic acid comprises from about 1.0 to about 10.0, more preferably from about 4.0 to about 8.0, percent by weight hydrochloric acid. The use of acid in this manner also advantageously facilitates avoidance of partial hydrolysis of the antimony trichloride to antimony oxychlorides.

Once the organic solvent comprising antimony trichloride has been scrubbed (if necessary), it is desirable to contact the organic solvent with an aqueous solution capable of extracting antimony trichloride from the organic solvent to the aqueous solution. Thus, the purpose of this extraction is to strip the antimony trichloride from the tributyl phosphate-containing organic solvent. It has been discovered that an aqueous solution containing ammonium chloride is particularly well suited for this purpose. Preferably, the aqueous solution used for this purpose comprises ammonium chloride in an amount in the range of from about 125 to about 250 g/L, most preferably from about 200 to about 250 g/L.

Thus, solvent extraction station C preferably comprises separate stages for solvent extraction, scrubbing and stripping. In the solvent extraction stage, the ratio of the organic phase volume to the aqueous phase volume (hereinafter referred to as the O/A ratio) is preferably in the range of from about 1.0 to about 3.0, most preferably from about 1.8 to about 2.2. It is also preferred that the solvent extraction stage comprise from 1 to 4, most preferably 2, sequential tanks. In the scrubbing stage, the O/A ratio is preferably in the range of from about 2.0 to about 20.0, most preferably from about 3.0 to about 8.0. It is also preferred that the scrubbing stage comprise from 2 to 10, most preferably 4, sequential tanks. In the stripping stage, the O/A ratio is preferably in the range of from about 1.0 to about 3.0, most preferably from about 1.8 to about 2.2. It is also preferred that the stripping stage comprise from 4 to 8, most preferably 6, sequential tanks.

Thus, after the stripping operation in solvent extraction station C, an aqueous solution comprising ammonium chloride and substantially pure antimony trichloride is produced. This solution is then fed to hydrolysis station D wherein the antimony trichloride is hydrolyzed to produce antimony trioxide.

In a preferred embodiment of the present process, prior to hydrolysis station D, the oxidation-reduction potential (hereinafter referred to as ORP) of the aqueous solution comprising ammonium chloride (i.e. the solution from the stripping stage of solvent extraction station C) is determined and adjusted, if necessary, by addition any suitable oxidizing agent such as hydrogen peroxide, sodium hypochlorite or the like, such that the ORP is in the range of from about 5 to about 100 ORP, most preferably from about 20 to about 50 mV. Determination of ORP can be achieved using a conventional ORP probe and is within the scope of a person skilled in the art. It has been determined that control of the ORP in this manner improves the colour (i.e. the whiteness) of the antimony trioxide eventually produced.

In hydrolysis station D, it is preferred to contact the aqueous solution comprising antimony trichloride with an aqueous base to produce particulate antimony trioxide. The base should be one which is capable of converting the antimony trichloride to antimony trioxide--see, for example, Canadian patent 1,014,332 (Shafer), the contents of which are hereby incorporated by reference.

Preferably, the base is selected from the group comprising alkali metal bases (e.g. alkali metal chlorides and alkali metal hydroxides), alkaline earth metal bases (e.g. alkaline earth metal chlorides and alkaline earth metal hydroxides) and ammonium bases (e.g. ammonium hydroxide).

The most preferred base for use in hydrolysis station D is ammonium hydroxide. One of the significant advantages of using ammonium hydroxide is that, since it is the conjugate base of the preferred salt (i.e. ammonium chloride) used in the strip operation in solvent extraction station C, ammonium hydroxide may be readily recovered, recycled and reused in the present process. It is especially preferred to use a base comprising ammonium hydroxide at a concentration of from about 8 to about 30, most preferably from about 8 to about 12, percent by weight.

Preferably, the base is used in an amount to maintain the pH of the reaction mixture in the range of from about 7.0 to about 9.0, most preferably from about 8.0 to about 8.5. Maintaining the pH of the reaction mixture in this manner facilitates production of senarmontite crystalline form of antimony trioxide.

Although not wishing to be bound by any particular theory or mode of action, it is believed that, when ammonium hydroxide is used as the base in hydrolysis station D and pH is controlled to facilitate formation of the senarmontite crystalline form of antimony trioxide, ammonium hydroxide reacts overall with antimony trichloride in the following manner:

2SbCl.sub.3 +6NH.sub.4 OH.fwdarw.Sb.sub.2 O.sub.3 +6NH.sub.4 Cl+3H.sub.2 O

When ammonium hydroxide is used in hydrolysis station D, the reaction with antimony trichloride is exothermic. The water in the reaction system should be sufficient to absorb the heat of reaction from hydrolysis. However, in certain cases it may advantageous to cool the vessel in which hydrolysis occurs to maintain the temperature at less than about 40.degree. C., preferably in the range of from about 0.degree. to about 20.degree. C., most preferably in the range of from about 10.degree. to about 15.degree. C.

Preferably, the antimony trichloride and the ammonium hydroxide are contacted in hydrolysis station D for a period of less than about 20 minutes, more preferably from about 5 seconds to about 15 minutes, most preferably from about 5 seconds to about 10 minutes.

Thus, after hydrolysis in hydrolysis station D, an aqueous liquid comprising substantially pure antimony trioxide in suspension is produced. This aqueous liquid containing antimony trioxide in suspension is then fed to dewatering/drying station E via line 25.

In dewatering/drying station E, the aqueous liquid is washed and dewatered using conventional counter-current washing/dewater techniques, preferably in a sequential manner. Thus, in drying station E, the aqueous liquid is initially fed to a conventional liquid/solid separator (not shown) wherein bulk antimony trioxide is separated from the aqueous liquid. The bulk antimony trioxide is then fed to a conventional drier (not shown), wherein drying of the antimony trioxide is effected. The dried antimony trioxide is then fed to a packaging station (not shown) wherein it is bagged or otherwise packaged for shipment to the end user.

As discussed hereinabove, one of the key advantages of the present process is the ability to recycle and reuse many of the reagents. The result of this is that the present process may be regarded as a substantially closed or near-closed loop, requiring little or no virgin reagents. Thus, the present process mitigates or obviates the high costs associated with purchase of virgin reagents for continuous production of antimony trioxide.

Thus, with reference to the accompanying FIGURE, the aqueous hydrochloric acid from the scrubbing operation (i.e. containing trace amounts of iron (II) compounds) of solvent extraction station C may be recycled to leach station B. This facilitates recovery of iron from solvent extraction station C.

A portion of the ammonium chloride produced as a by-product during hydrolysis may be recycled to solvent extraction station C wherein it may be used in the stripping operation discussed hereinabove. The remaining portion of the ammonium chloride may be fed to ammonium recovery station G. In ammonium recovery station G, the ammonium chloride is converted to ammonium hydroxide pursuant to the following overall reaction:

NH.sub.4 Cl+NaOH.fwdarw.NH.sub.4 OH.uparw.+NaCl

The ammonium hydroxide is produced in gaseous form which may be readily absorbed by and dissolved in water to produce an aqueous solution of ammonium hydroxide. The aqueous solution of ammonium hydroxide may be recycled to the hydrolysis station D via line 95 wherein it may be used in the hydrolysis reaction discussed hereinabove. The sodium chloride solution is fed to brine purification station H. In brine purification station H, residual heavy metal impurities are removed from the sodium chloride solution.

The choice, design and operation of equipment for use in ammonium recovery station G and brine purification station H is within the purview of a person skilled in the art.

The concentrated sodium chloride solution produced in brine purification station H is fed to chloro-alkali electrolysis station I. In chloro-alkali electrolysis station I, the concentrated sodium chloride solution is electrolyzed to produce chlorine gas and sodium hydroxide. Hydrochloric acid is also a product of chlorine combination with hydrogen. While not wishing to be bound by any particular theory or mode action, it is believed that the following overall reactions occur in the chloro-alkali system:

2NaCl+2H.sub.2 O.fwdarw.Cl.sub.2 .uparw.+2NaOH+H.sub.2 .uparw.H.sub.2 +Cl.sub.2 +.DELTA..fwdarw.2HCl

A portion or all of the aqueous sodium hydroxide produced in chloro-alkali electrolysis station I is fed via line 65 to ammonium recovery station G wherein the aqueous hydroxide solution is used as described hereinabove to convert ammonium chloride to ammonium hydroxide. The remaining portion of the aqueous sodium hydroxide produced in chloro-alkali electrolysis station I may, if necessary, be fed via line 70 to brine purification station H wherein it may be used to adjust the pH of the concentrated sodium chloride solution eventually fed to chloro-alkali electrolysis station I. The hydrochloric acid produced in chloro-alkali electrolysis station I may be recycled to: line 40 (containing ammonium chloride) via line 80 and/or solvent extraction station C via line 90.

The choice, design and operation of equipment for use in chloro-alkali electrolysis station I is within the purview of a person skilled in the art.

A portion of the chlorine gas produced in chloro-alkali electrolysis station I is fed to chlorination station F via line 60. In chlorination station F, chlorine gas reacted with iron (II) chloride from solvent extraction station C pursuant to the following overall reaction:

2FeCl.sub.2 +Cl.sub.2 .fwdarw.2FeCl.sub.3

Thus, chlorination station F serves to regenerate iron (III) chloride which is then recycled to leach station B via line 30.

The choice, design and operation of equipment for use in chlorination station F is within the purview of a person skilled in the art.

While specific illustrated embodiments have been discussed hereinabove with respect to the attached drawings, it should be clearly understood that variations to and modifications of the illustrated embodiments will become apparent to those of skill in the art which do not depart from and are intended to be included within the spirit and scope of the invention. It is the intent of the Applicant that such variations and modifications are included with in the sprit and scope of the invention.





Sam Xu
Sales Engineer

DONGGUAN JIEFU FLAME-RETARDED MATERIALS CO.,LTD
Address: jiefu industrial park shuiping industrail district dalang town dongguan GD,P.R.C
Zip: 528770
Tel: 0086-755-83474911
FAX: 0086-755-83474980
Mobile:13929211059
Contact me: xubiao_1996@hotmail.com samjiefu@gmail.com

Jiefu Chemical industry LTD . (Our imports and exports company )

Chinese antimony market



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[+/-] : Features of antimony trioxide as catalysts

Antimony compounds are excellent catalysts to accelerate the polymerization in polyester manufacturing.
Antimony trioxide is the most widely used polymerization catalyst in both domestic and overseas markets in the manufacture of polyethylene terephthalate(PET)from ethylene glycol(EG)and high purity terephthalic acid(TPA), or dimethyl terephthalete(DMT).
PATOX-C and PATOX-CF when used as polymerization catalysts have the following excellent physical properties.

(1) PATOX-C & -CF for use in polyester when it is required to be stable in heat. They are high purity products low in metallic impurities to safeguard against undesirable side-reactions in the manufacturing process.
(2) PATOX-C & -CF contain less insolubles when dissolved in ethylene glycol. This leads to lower production maintenance requirements by minimizing the clogging of filter taps, and also minimizing operation interruption by reducing yarn cuts in polyester yarn production.
(3) PATOX-C & -CF are produced in large homogeneous lot sizes with precise production standards and controls. This provides a stable quality product which facilitates the production of a polyester with high transparency and sharp coloring.
(4) PATOX-CF, a finer type of PATOX-C, dissolves into ethylene glycol at lower temperatures.
Catalyst grade of antimony trioxide should be used in accordance with the above process.
(A): CAT(Catalyst) dissolving tank
(B): CAT storage tank
(C): CAT measuring tank
(D): Slurry preparing tank
(E): Slurry storage tank
Preparation-methods of catalyst
(I) EG and catalyst are placed into CAT dissolving tanks(A).
Concentration of Sb2O3 is around 2.0% (To maintain fixed concetration)
(II) The catalyst is dissolved by heating and stripping at 130-180℃ for 3-6 hours, cooled to 50-70℃, and then transferred to CAT storage tank(B).
(III) A fixed quantity of solution is charged to CAT measuring tank(C), and then transferred to Slurry preparing tank(D).



Sam Xu
Sales Engineer

DONGGUAN JIEFU FLAME-RETARDED MATERIALS CO.,LTD
Address: jiefu industrial park shuiping industrail district dalang town dongguan GD,P.R.C
Zip: 528770
Tel: 0086-755-83474911
FAX: 0086-755-83474980
Mobile:13929211059
Contact me: xubiao_1996@hotmail.com samjiefu@gmail.com

Jiefu Chemical industry LTD . (Our imports and exports company )

Chinese antimony market



DONGGUAN JIEFU FLAME-RETARDED MATERIALS CO.,LTD...
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[+/-] : Antimony Triacetate

Properties: White crystal powder,melting point 124 ��C, Molecular formula: Sb(CH2COO)3




Application: Mainly used as catalyst for poly-condensation of polyester. Improved Poly-condensation time especially in continuous processes. Significantly reduced impurity levels in PET resin.

Packing: 12.5kg in polyethylene drum,36 drums/pallet, lined with double layers polyethylene bag or as customer's requirement.




Sam Xu
Sales Engineer

DONGGUAN JIEFU FLAME-RETARDED MATERIALS CO.,LTD
Address: jiefu industrial park shuiping industrail district dalang town dongguan GD,P.R.C
Zip: 528770
Tel: 0086-755-83474911
FAX: 0086-755-83474980
Mobile:13929211059
Contact me: xubiao_1996@hotmail.com samjiefu@gmail.com

Jiefu Chemical industry LTD . (Our imports and exports company )

Chinese antimony market



DONGGUAN JIEFU FLAME-RETARDED MATERIALS CO.,LTD...
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[+/-] : Antimony Glycolate

Properties:White crystal, colorless and non-toxicity, easy to deliquesce in damp air and excellent solubility in ethylene glycol. Higher oxidation states of antimony and inert materials are absent. Rigorous control of the manufacturing process ensures an extremely consistent product.



Molecular formula: Sb2(C2H4O2)3
Molecular weight: 423.66
Specification:
Name of index

Index
Content of Antimony(Sb)%

56.0-58.8
Loss on Drying %

0.6
Tartaric Acid Insolubles%

0.014
CIE L

94
CIE A

-1.0-2.0
CIE B

-1.5-2.8
Arsenic (As) ppm

16
Lead (Pb) ppm

11
Through 20 Mesh %

98

Application: Catalyst for poly-condensation of polyester, it is a very active polycondensation catalyst and can be added at either the direct esterification or the polycondensation stage of the process. It is optimized for use in conjunction with the titanium based polyester catalyst technology. The absence of the acetate anion can be an advantage to some polyester manufacturers.

Packing:20 in polyethylene drum lined with double layers polyethylene bag or as customer's requirement.

Antimony Glycolate��New Type, High Efficiency Polyester Catalyst

Brief Introduction for New Type ,High Efficiency Polyester Catalyst ---Antimony Glycolate Antimony Glycolate, new type of catalyst for polyester production, which activates relative reactant, accelerates reaction, finally taken catalysis.

At present, there are three regular kinds of PET catalysts in and aboard, viz,

antimony trioxide, antimony triacetate and antimony glycolate .As far as the catalyzed effect is concerned antimony trioxide is not as good as antimony triacetate,. however, antimony glycolate is superior than both of them, thus, becomes the best catalyst nowadays. which provided with excellent catalyst activity and obviously expedited polycondensation.

As far as the quality effects to final products and re-produced products are concerned, Antimony Glycolate is the best, antimony triacetate is secondly and

antimony trioxide is the third one .Most important reasons of these: There is high percentage of impurity in antimony trioxide catalyst, especially Sb 0+, Sb 5+, Fe metals and metal compounds which all will affect the product quality such as:

Not good color, high gloomy degree, more agglomerate particles, worse weave possibility.So antimony trioxide is rarely adopted especially in bottle slice up ,film slice up and distinction polyester production . Contrarily with less impurity antimony triacetate and antimony glycolate are provided with high quality and perfect color for final product.

No matter antimony trioxide or antimony triacetate they should be confected inglycol solution during application, antimony hydronium and glyol gene form chelated material, that is antimony glycolate .There is need of definite conditions for forming this chelated material .For example: Antimony Trioxide begins to slowly dissolve in confected glycol solution at 150 o C and form antimony chelated, meanwhile release small molecule water .However antimony triacetate can be dissolved at lower degree even 60 o C and form both antimony glycolate and antimony triacetate . The above mentioned two processes are all chemical reaction, but antimony glycolate confecting is physics reaction without any other chemical material and pollution. Antimony Trioxide confect process bring water and antimony triacetate confect process bring acetate which are all disadvantage for reaction, especially acetate brought from antimony triacetate reaction which will canker equipment ..On the other hand antimony triacetate react with antimony triacetate to consume glycol which will increase glyol consumption..

However antimony glycolate reactions not only not consume glycol but also parse additional glycol from itself which is the raw material for polyester production .Therefore antimony glycolate catalyst application can debase glycolconsumption .

With lower impurity antimony glycolate product can guarantee high quality tofinal product and improve filature grade rate. It is reported both in and abroadantimony glycolate catalyst can reduce POY filature decollation rate by 10-15% ,extend discreteness cleanout schedule by 50% reduce weave cease degree by 50% .

Based on Sb content of 57.4% in Antimony Glycolate and 40.7% content in Antimony Triacetate there is percentage gap of 16.7% between them .Used antimony glycolate as catalyst will be reduced 30% dosage than antimony triacetate catalyst .According to economy point of views there will be less production cost for antimony glycolate application for which price is less than antimony triacetate .

Based on special technology crystal antimony glycolate is more stable than antimony triacetate and double-quick dissolved speed than any other same items in China.




Sam Xu
Sales Engineer

DONGGUAN JIEFU FLAME-RETARDED MATERIALS CO.,LTD
Address: jiefu industrial park shuiping industrail district dalang town dongguan GD,P.R.C
Zip: 528770
Tel: 0086-755-83474911
FAX: 0086-755-83474980
Mobile:13929211059
Contact me: xubiao_1996@hotmail.com samjiefu@gmail.com

Jiefu Chemical industry LTD . (Our imports and exports company )

Chinese antimony market



DONGGUAN JIEFU FLAME-RETARDED MATERIALS CO.,LTD...
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