CN101445275A - Centrifugal extracting method for preparing ammonium tungstate solution from soda leach liquor of tungsten contained material - Google Patents

Abstract

The invention discloses a centrifugal extracting method for preparing ammonium tungstate solution from soda leach liquor of tungsten contained material. The method takes the trialkyl methyl ammonium carbonate as extractant containing tungsten materials directly from the leaching solution of soda extraction tungsten; then the impurities of phosphorus, arsenic, silicon, such as stripping more than stay in solution with separation of tungsten, tungsten negative organic phase after washing with detergent as ammonium bicarbonate and ammonium carbonate extraction of the mixed solution to obtain high-purity tungsten perchlorate solution, anti-organic phase after extraction with sodium hydroxide solution using renewable, recycled back to the organic phase after extraction, extraction, extraction operations are carried out the centrifugal extractor. The invention achieves the invention sodium perchlorate solution to the transformation of tungsten, and the invention removes the phosphorus, arsenic, silicon and other impurities, stripping more than the use of liquid can be returned to leaching. The extraction and anti-extraction process of the invention has a fastseparation, short process, and small chemical reagent consumption, waste water emissions from small, easy to achieve industrialization.

Description

Method for preparing ammonium tungstate solution by centrifugal extraction from tungsten-containing material soda leachate

technical field

The invention relates to a tungsten hydrometallurgical method, in particular to a method for preparing ammonium tungstate solution by centrifugal extraction from tungsten-containing material soda leaching solution.

Background technique

Tungsten is an important rare metal element and has a wide range of uses in industry. Industrially, tungsten is extracted from various tungsten-containing materials, including tungsten mineral resources (such as scheelite, wolframite, black and white tungsten mixed ore, etc.), secondary resources of tungsten (such as waste tungsten-containing catalysts, etc.) And various intermediate materials in the production process of tungsten industry.

Soda high-pressure leaching method and soda sintering-water leaching method are two mature methods for leaching tungsten from tungsten-containing materials in industry. The leaching solution obtained by the above two leaching methods is a mixed solution of sodium tungstate and sodium carbonate, which usually contains a small amount of P, As, Si and other impurities. This solution is the tungsten-containing material soda leaching solution.

An important method for preparing ammonium tungstate solution from the above tungsten-containing material soda leach solution is solvent extraction. The extraction method currently used in the industry uses weakly basic polymer amines (such as polymer tertiary amines, primary amines, secondary amines, etc.) Ammonium tungstate solution is obtained by back extraction with ammonia water. This extraction method is called acidic extraction. There is following shortcoming in above-mentioned acidic extraction method: (1) must be adjusted to acidity (pH value 2～4) containing the leach solution of a large amount of free sodium carbonates, both wasted the free sodium carbonate in the leach solution and consumed a large amount of mineral acid (sulfuric acid or hydrochloric acid), and the inorganic salts produced by acid-base neutralization will also pollute the environment; (2) due to P, As, and Si can form heteropolyacid radicals with tungsten under acidic conditions, impurities such as P, As, and Si will form in the extraction process It is extracted into the organic phase together with tungsten, so the acidic extraction method does not have the function of removing P, As, Si and other impurities and can only convert sodium tungstate solution into ammonium tungstate solution. Impurities P, As, Si, etc. need to be pre-removed in sodium tungstate solution by chemical precipitation method (magnesium salt method or ammonium magnesium salt method), the consumption of chemical reagents is large and there is loss of tungsten in the process.

For the above-mentioned problems of acidic extraction, Russian scholar V.P.Zaitsev et al. proposed a method to extract directly from tungsten ore soda high-pressure leaching solution in the Proceedings of International Conference of Hydrometallurgy (Proceedings of International Conference of Hydrometallurgy, Changsha, 1992: 768). A method of extracting tungsten to prepare ammonium tungstate solution. In this method, the tungsten in the high-pressure leaching solution of tungsten ore soda is directly extracted with the carbonate of high molecular weight quaternary ammonium, and the impurities P, As, Si, etc. are left in the raffinate. It is separated from tungsten, and the negative tungsten organic phase is stripped with ammonium bicarbonate solution to obtain ammonium tungstate solution. After the reverse, the organic phase is regenerated with sodium hydroxide solution. The regenerated organic phase is returned to extraction, and the raffinate produced by extraction is returned to leaching. This method of tungsten extraction is carried out under alkaline conditions (pH>8), which was first proposed by Russian scholars. We call this method the Russian alkaline extraction method.

The Russian alkaline extraction method can realize the separation of impurities P, As, Si, etc. from tungsten while transforming (converting sodium tungstate solution into ammonium tungstate solution). The alkali in the leaching solution is recovered and the waste water discharged outside is reduced. Compared with the acidic extraction method, the Russian alkaline extraction method has a shorter process, less consumption of chemical reagents and less waste water discharge. However, this method has not been applied in large-scale industry so far. The reason is that the method still has the following problems: (1) The phase separation performance of the extraction and stripping process of the extraction system is poor, especially when the concentration of the extractant is high or the flow rate is high. When the ratio (the ratio of organic phase to aqueous phase volume flow rate, the same below) is large, this situation is particularly serious, resulting in the slow speed of phase separation of extraction and back extraction when conventional extraction equipment (such as mixing and settling tanks) is used, and the operating conditions It is harsh, the processing capacity of the extraction equipment is small, and even the extraction and stripping operations cannot be carried out; (2) The WO ₃ concentration of the stripping liquid is too low, and the WO ₃ concentration of the stripping liquid can only reach about 100g/L, if it continues to increase, there will be crystallization of ammonium paratungstate Precipitate from it, its reason is that the pH value of ammonium bicarbonate solution is too low. However, the low concentration of _WO3 in the stripping solution leads to a large energy consumption for subsequent evaporation and crystallization to prepare ammonium paratungstate.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the shortcomings of the acidic extraction method and the Russian alkaline extraction method, and provide a method for preparing ammonium tungstate solution by centrifugal extraction from the tungsten-containing material soda leaching solution. The method has a short process flow and consumes chemical reagents. Small, good for environmental protection.

Technical solution of the present invention is as follows:

A method for preparing ammonium tungstate solution by centrifugal extraction from tungsten-containing material soda leachate, characterized in that it comprises the following steps:

1) Extraction process: use the organic phase containing the extractant and the tungsten-containing material soda leachate to conduct multi-stage countercurrent extraction in multiple series-connected centrifugal extractors;

2) Stripping process: the loaded organic phase obtained after extraction is washed with detergent, and then the mixed solution of ammonium bicarbonate and ammonium carbonate is used as the stripping agent to carry out multi-stage countercurrent stripping in multiple centrifugal extractors connected in series to obtain tungsten ammonium acid solution.

The organic phase obtained after the step 2) multistage countercurrent back extraction is regenerated with an aqueous solution containing free sodium hydroxide, and then returns to step 1) to add to the extraction process.

The extractant in the step 1) is methyltrialkylammonium carbonate, wherein each alkyl group contains 8-10 carbon atoms.

The volume percent concentration of the carbonate of methyltrialkylammonium extractant in the organic phase is between 10% and 60%.

The concentration of _WO3 in the soda leach solution of the tungsten-containing material is 10-150 g/L.

Both the extraction process and the stripping process are carried out in a centrifugal extractor.

The volume flow ratio (i.e., flow ratio) of the organic phase to the tungsten-containing material soda leachate during the extraction process is 1/10 to 10/1, and the volume flow rate of the organic phase to the "mixed solution of ammonium bicarbonate and ammonium carbonate" during the stripping process The ratio is 2/1 to 10/1.

The number of extraction stages in step 1) is 3-15 stages, and the number of back-extraction stages in step 2) is 5-20 stages.

The main component of the raffinate produced in the extraction process of the above step 1) is sodium carbonate solution, which can be returned to the soda leaching process of tungsten-containing materials for use.

The present invention adopts two aspects of measures to solve the problems of the Russian alkaline extraction method.

On the one hand, the present invention adopts centrifugal extractor to replace mixing and settling tank to carry out extraction and stripping operation, and its purpose is to overcome the slow phase separation speed of extraction and stripping process in the alkaline extraction system, especially when extractant concentration is high or flow ratio The problem of slow phase separation during large periods of time. Centrifugal extractor is an extraction equipment that realizes phase separation in a centrifugal force field. Compared with mixing and settling tanks, tower extractors and other extraction equipment that separate phases under a gravity field, it has the advantages of good phase separation performance and a wide range of operable flow ratios. , can realize rapid mixing and rapid phase separation of extraction and back extraction in alkaline extraction system, especially when the concentration of extractant is high or the flow ratio is large.

On the other hand, the present invention adopts the mixed solution of ammonium bicarbonate and ammonium carbonate to replace ammonium bicarbonate solution as stripping agent, the pH value of the mixed solution of ammonium bicarbonate and ammonium carbonate is higher than the pH value of ammonium bicarbonate solution, thereby can Preventing the crystallization of ammonium paratungstate due to the low pH value when the concentration of WO ₃ in the back extraction solution is increased, breaking through the limitation of the ammonium bicarbonate system on the concentration of WO ₃ , and creating conditions for increasing the concentration of WO ₃ in the back extraction solution. The above stripping agent ammonium bicarbonate and ammonium carbonate mixed solution can be obtained by dissolving solid ammonium carbonate and solid ammonium bicarbonate in water in practice, and can also be obtained by mixing ammonium bicarbonate solution with ammonia water (or liquid ammonia).

The present invention can effectively solve the problems of difficult phase separation in the alkaline extraction system and low concentration of WO ₃ in the stripping liquid by adopting the measures of the above two aspects at the same time, so that the alkaline extraction method is easy to be realized industrially.

Compared with the acidic extraction method adopted in the current industry, the present invention has the following advantages: (1) the extraction of tungsten in the present invention is directly carried out in an alkaline medium, without consuming inorganic acid to neutralize the free alkali and the tungsten-containing material soda leachate Adjust acidity; (2) The present invention can realize the separation of impurities P, As, Si, etc. from tungsten while transforming (converting sodium tungstate solution into ammonium tungstate solution), eliminating the need for chemical precipitation to remove P, As, Si (3) The raffinate of the present invention is a sodium carbonate solution, which can be directly returned to the soda leaching of tungsten-containing materials for use, and can form a closed-circuit cycle of water with the leaching process, which not only reclaims sodium carbonate, but also reduces waste water discharge. For specific experimental data, see the examples.

Description of drawings

Figure 1 is a process flow chart for preparing ammonium tungstate solution by centrifugal extraction from tungsten-containing material soda leachate.

Detailed ways

The implementation of the present invention will be described below with reference to the accompanying drawings and examples.

Figure 1 represents a process flow diagram of the present invention. In the technological process shown in Fig. 1, the extractant is the carbonate of methyltrialkylammonium, the extractant and the polarity improving agent (such as secondary octanol, tributyl phosphate) and diluent (such as sulfonated kerosene) The organic phase is composed; the feed liquid is the soda leaching solution of tungsten-containing materials, which is a mixed solution of sodium tungstate and sodium carbonate, which usually contains a small amount of P, As, Si and other impurities; the above organic phase and the feed liquid According to a certain flow ratio, rapid mixing and phase separation are carried out in multiple centrifugal extractors connected in a countercurrent manner to realize a multistage countercurrent extraction process. In this process, tungsten is extracted into the organic phase, and impurities P, As, Si, etc. The liquid is discharged and separated from the tungsten. After the loaded organic phase is washed with a detergent (such as deionized water), the mixed solution of ammonium bicarbonate and ammonium carbonate is used as the stripping agent to perform rapid mixing and phase separation in multiple centrifugal extractors connected in a countercurrent manner at a certain flow ratio. , to achieve a multi-stage countercurrent stripping process to obtain a higher purity ammonium tungstate solution. The organic phase after stripping is regenerated with a solution containing free sodium hydroxide and then returned to extraction. The main component of the raffinate produced in the above extraction process is sodium carbonate solution, which can be returned for leaching.

Example 1

Composition of tungsten-containing material soda leachate: WO ₃ 10.0g/L, Na ₂ CO ₃ 20.5g/L, P 0.02g/L, As 0.01g/L, Si0.03g/L;

Organic phase: pre-prepared organic phase composed of 60% N263+20% 2-octanol+20% sulfonated kerosene (volume percentage concentration), wherein N263 is the product code of domestic quaternary ammonium salt extractant, which is a kind of methyl trimethyl Alkyl ammonium chloride, wherein the carbon atoms in the three alkyl groups are 8-10. Before extraction, the organic phase is contacted with sodium carbonate solution several times to convert the methyltrialkylammonium chloride in the organic phase into the carbonate of methyltrialkylammonium, and the extractant is in the organic phase The volume percent concentration is 60%, and this organic phase is used as the organic phase of extraction.

Operation: The above-mentioned organic phase and tungsten-containing material soda leachate are subjected to 7-stage countercurrent extraction under the condition of a flow ratio of 1/10. The extraction equipment is an annular gap centrifugal extractor, and the negative tungsten organic phase is used with deionized water at a flow ratio of 3/1. After washing, use 2.5mol/LNH ₄ HCO ₃ + 1.0mol/L(NH ₄ ) ₂ CO ₃ mixed ammonium solution to carry out 10-stage countercurrent back extraction. The back extraction equipment is also an annular gap centrifugal extractor, and the back extraction flow ratio is 2 /1, after the reaction, the organic phase is returned to extraction after single-stage regeneration treatment with 2mol/L NaOH aqueous solution under the condition of 1.5/1.

Results: The back-extraction solution was ammonium tungstate solution with high purity, the concentration of WO ₃ in it was 190.0g/L, P<0.0001g/L, As<0.0006g/L, Si<0.0006g/L.

Example 2

Composition of tungsten-containing material soda leachate: WO ₃ 150.0g/L, Na ₂ CO ₃ 80.3g/L, P 0.020g/L, As 0.011g/L, Si 0.032g/L.

Organic phase: an organic phase whose composition is 10% methyl trinonyl ammonium chloride + 10% sec-octanol + 80% sulfonated kerosene (volume percentage concentration) is prepared in advance. Before extraction, the organic phase is contacted with sodium carbonate solution several times to convert the methyltrinonylammonium chloride in the organic phase into the carbonate of methyltrialkylammonium, and the extractant is in the organic phase The volume percentage concentration is 10%, and this organic phase is used as the organic phase of extraction.

Operation: The above-mentioned organic phase and tungsten-containing material soda leachate are subjected to 15-stage countercurrent extraction under the condition of a flow ratio of 10/1. The extraction equipment is an annular centrifugal extractor, and the negative tungsten organic phase is deionized with water at a flow ratio of 5/1. After washing, use 2.0mol/LNH ₄ HCO ₃ +1.0mol/L(NH ₄ ) ₂ CO ₃ mixed ammonium solution to perform 20-stage countercurrent back extraction. The back extraction equipment is also an annular centrifugal extractor, and the back extraction flow ratio is 10 /1, after the reaction, the organic phase is returned to the extraction after single-stage regeneration treatment with 1mol/L NaOH aqueous solution under the condition of 5/1.

Results: The stripping liquid was ammonium tungstate solution with high purity, the concentration of WO ₃ in it was 145.0g/L, P<0.0001g/L, As<0.0005g/L, Si<0.0005g/L.

Example 3

Composition of tungsten-containing material soda leachate: WO ₃ 100.2g/L, Na ₂ CO ₃ 90.5g/L, P 0.13g/L, As 0.04g/L, Si 0.24g/L.

Organic phase: an organic phase whose composition is 60% methyl trioctyl ammonium chloride + 20% sec-octanol + 20% sulfonated kerosene (volume percentage concentration) is prepared in advance. Before the extraction, the organic phase is contacted with sodium carbonate solution several times to convert the methyl trioctyl ammonium chloride in the organic phase into the carbonate of methyl trialkyl ammonium, and the extractant is in the organic phase The volume percent concentration is 60%, and this organic phase is used as the organic phase of extraction.

Operation: The above organic phase and tungsten-containing material soda leachate are subjected to three-stage countercurrent extraction under the condition of a flow ratio of 1.5/1. The extraction equipment is an annular centrifugal extractor, and the negative tungsten organic phase is deionized with water at a flow ratio of 3/1. After washing, use 2.0mol/LNH ₄ HCO ₃ +0.5mol/L(NH ₄ ) ₂ CO ₃ mixed ammonium solution to carry out 5-stage countercurrent back extraction. The back extraction equipment is also an annular gap centrifugal extractor, and the back extraction flow ratio is 3 /1, after the reaction, the organic phase is returned to extraction after single-stage regeneration treatment with 3mol/L NaOH aqueous solution under the condition of 2.5/1.

Results: The back-extraction solution was ammonium tungstate solution with high purity, the concentration of WO ₃ in it was 165.0g/L, P<0.01g/L, As<0.002g/L, Si<0.005g/L.

Claims (8)

1. One kind from soda leach liquor of tungsten contained material Centrifugical extraction produce the method for ammonium tungstate solution, it is characterized in that, may further comprise the steps:

   1) extraction process: in many placed in-line centrifugal extractors, carry out multi-stage counter current extraction with organic phase and the soda leach liquor of tungsten contained material that contains extraction agent;

   2) reextraction process: the mixing solutions of the load organic phases that obtains after the extraction through adopting bicarbonate of ammonia and volatile salt behind the detergent washing is that reverse-extraction agent carries out the multi-stage countercurrent reextraction in many placed in-line centrifugal extractors, obtains ammonium tungstate solution.
2. 2. as claimed in claim 1 from soda leach liquor of tungsten contained material Centrifugical extraction produce the method for ammonium tungstate solution, it is characterized in that described step 2) organic phase that obtains after stripping of multi-stage countercurrent carries out turning back to step 1) again after the manipulation of regeneration with the aqueous solution that contains free sodium hydroxide and adds extraction process.
3. 3. as claimed in claim 1 from soda leach liquor of tungsten contained material Centrifugical extraction produce the method for ammonium tungstate solution, it is characterized in that the extraction agent in the described step 1) is the carbonate of methyltrialkylammonium, wherein contain 8～10 carbon atoms in each alkyl.
4. 4. as claimed in claim 3 from soda leach liquor of tungsten contained material Centrifugical extraction produce the method for ammonium tungstate solution, it is characterized in that the concentration of volume percent of the carbonate of described extraction agent methyltrialkylammonium in organic phase is between 10%～60%.
5. 5. as claimed in claim 1 from soda leach liquor of tungsten contained material Centrifugical extraction produce the method for ammonium tungstate solution, it is characterized in that WO in the described soda leach liquor of tungsten contained material ₃Concentration is 10～150g/L.
6. 6. as claimed in claim 1 from soda leach liquor of tungsten contained material Centrifugical extraction produce the method for ammonium tungstate solution, it is characterized in that described extraction process and reextraction process are all carried out in centrifugal extractor.
7. 7. as claimed in claim 1 from soda leach liquor of tungsten contained material Centrifugical extraction produce the method for ammonium tungstate solution, it is characterized in that, the volume flow ratio of organic phase and soda leach liquor of tungsten contained material is 1/10～10/1 in the extraction process, and organic phase is 2/1～10/1 with the volume flow ratio of " mixing solutions of bicarbonate of ammonia and volatile salt " in the reextraction process.
8. As claim 1～7 each described from soda leach liquor of tungsten contained material Centrifugical extraction produce the method for ammonium tungstate solution, it is characterized in that the extraction progression in the step 1) is 3～15 grades, step 2) in reextraction progression be 5～20 grades.