阅读说明：本技术 一种低品位白钨矿的处理方法 (Treatment method of low-grade scheelite ) 是由 赵中伟 刘旭恒 陈星宇 李江涛 何利华 孙丰龙 于 2021-01-20 设计创作，主要内容包括：本发明公开了一种低品位白钨矿的处理方法,将低品位白钨矿加入到稀盐酸中进行酸洗,得到酸洗渣和酸洗液；将酸洗渣加入到盐酸-磷酸混酸溶液中,在70-95℃下搅拌反应1-5h后得到混酸分解液；将浓硫酸加入到混酸分解液中反应,搅拌5min后过滤,得到高纯石膏渣和滤液；用TBP萃取体系萃取滤液中的钨,得到负载有机相和萃余液,萃余液经补加磷酸和盐酸后返回至步骤(2)重复使用；用氨水对负载有机相进行反萃,得到粗钨酸铵溶液用于后续APT的生产。本发明使矿物中的钨彻底进入到溶液中,进一步通过溶剂萃取的方式将溶液中的钨进行分离富集,实现钨资源的高效提取,为低品位白钨矿的资源利用提供一条新的途径。(The invention discloses a method for processing low-grade scheelite, which comprises the steps of adding the low-grade scheelite into dilute hydrochloric acid for acid washing to obtain acid washing slag and acid washing liquid; adding the acid washing slag into a hydrochloric acid-phosphoric acid mixed acid solution, and stirring and reacting at 70-95 ℃ for 1-5h to obtain a mixed acid decomposition liquid; adding concentrated sulfuric acid into the mixed acid decomposition liquid for reaction, stirring for 5min, and filtering to obtain high-purity gypsum residue and filtrate; extracting tungsten in the filtrate by using a TBP extraction system to obtain a loaded organic phase and raffinate, and returning the raffinate to the step (2) for reuse after supplementing phosphoric acid and hydrochloric acid; and (3) carrying out back extraction on the loaded organic phase by using ammonia water to obtain a crude ammonium tungstate solution for the subsequent APT production. The invention ensures that tungsten in minerals completely enters the solution, and further separates and enriches the tungsten in the solution in a solvent extraction mode, thereby realizing high-efficiency extraction of tungsten resources and providing a new way for resource utilization of low-grade scheelite.)

1. A method for processing low-grade scheelite is characterized by comprising the following steps:

(1) adding the low-grade scheelite into dilute hydrochloric acid for acid washing, and performing solid-liquid separation to obtain acid washing slag and acid washing liquid;

(2) adding the acid washing slag into a hydrochloric acid-phosphoric acid mixed acid solution, and stirring and reacting at 70-95 ℃ for 1-5h to obtain a mixed acid decomposition liquid;

(3) adding concentrated sulfuric acid into the mixed acid decomposition liquid obtained in the step (2) for reaction, stirring for 5min, and filtering to obtain high-purity gypsum residue and filtrate; extracting tungsten in the filtrate by using a TBP extraction system to obtain a loaded organic phase and raffinate, and returning the raffinate to the step (2) for reuse after supplementing phosphoric acid and hydrochloric acid; and (3) carrying out back extraction on the loaded organic phase by using ammonia water to obtain a crude ammonium tungstate solution for the subsequent APT production.

2. The method for treating low-grade scheelite according to claim 1, wherein the method comprises the following steps: in the step (1), WO is contained in the low-grade scheelite₃The content is 15-40 wt%.

3. The method for treating low-grade scheelite according to claim 1, wherein the method comprises the following steps: in the step (1), the liquid-solid ratio of the low-grade scheelite to the dilute hydrochloric acid is 1-5mL/g, and the concentration of the dilute hydrochloric acid is 10-50 g/L.

4. The method for treating low-grade scheelite according to claim 1, wherein the method comprises the following steps: in the step (1), the acid washing process comprises the following steps: stirring and reacting for 10-30 min at room temperature.

5. The method for treating low-grade scheelite according to claim 1, wherein the method comprises the following steps: in the step (2), the liquid-solid ratio of the acid washing slag to the hydrochloric acid-phosphoric acid mixed acid is 1-5 mL/g.

6. The method for treating low-grade scheelite according to claim 5, wherein the method comprises the following steps: in the hydrochloric acid-phosphoric acid mixed acid, the concentration of hydrochloric acid is 50-150g/L, and the concentration of phosphoric acid is 20-100 g/L.

7. The method for treating low-grade scheelite according to claim 1, wherein the method comprises the following steps: in the step (3), concentrated sulfuric acid is used according to Ca in the mixed acid decomposition liquid²⁺And H₂SO₄In a molar ratio of 1: 0.95-1 of the additive.

8. The method for treating low-grade scheelite according to claim 1, wherein the method comprises the following steps: in the step (3), the TBP extraction system is a mixed system of TBP with the volume fraction of 40-80% and kerosene with the volume fraction of 20-60%, the extraction ratio is 1:1-2, and the mixing time is 5-10 min.

Technical Field

The invention belongs to extraction of tungsten in the field of hydrometallurgy, and particularly relates to a treatment method of low-grade scheelite.

Background

The total reserves of tungsten resources in China account for more than 50% of the total reserves of the world, wherein scheelite is mainly used and accounts for about 78% of the total reserves. Along with continuous exploitation of tungsten resources, the endowment of the tungsten resources is continuously reduced, rich ores are less and less, the grade of more than 80% is less than 0.4%, the components are complex, and quite part of the tungsten resources are associated ores and are difficult to recycle (for example, the tungsten storage amount of the second tungsten leucotungsten ore, i.e., the goldenrain ore in China is as high as 62 ten thousand tons, but the grade of the raw ore is only 0.06%). Limited by the existing tungsten smelting process, WO is generally selected in the tungsten beneficiation process₃The tungsten concentrate with the content of more than 45 percent can meet the requirement of tungsten smelting, otherwise, the decomposition rate of the tungsten smelting falls off rapidly. Along with the natural endowment of tungsten resources, the beneficiation recovery rate of tungsten is gradually reduced from about 70 percent to 63-65 percent. In order to guarantee the beneficiation recovery rate of tungsten, the grade of tungsten concentrate has to be reduced, so that WO of the tungsten concentrate₃The grade is reduced to below 40 percent, and some is even as low as about 20 percent, which causes great challenges to the smelting of tungsten minerals. In the traditional tungsten smelting process, WO is decomposed₃The grade of the scheelite concentrate is 60 percent, and when the consumption of NaOH is 2.5 times of the theoretical amount, the slag contains WO₃Can be reduced to about 2.5 percent; and for WO₃The low-grade tungsten raw material with the content of about 20 percent is difficult to reach the same tungsten content level of slag when the alkali dosage is 4.5 to 6 times. In addition, researchers in China develop a new process for treating scheelite by a sulfur-phosphorus mixed acid method (Chinese patent inventions 2010106050951 and 2010106050947), and the efficient decomposition of the scheelite can be realized. However, the method has certain limitations when processing low-grade scheelite. The method is mainly characterized in that the generation of a large amount of calcium sulfate slag can wrap raw materials and prevent scheelite from further decomposition, so that WO is treated₃When the content of scheelite is 40% or less, the decomposition rate is only about 98%. Therefore, how to realize the high-efficiency extraction of tungsten in the low-grade scheelite is very important.

Disclosure of Invention

In order to solve the problems in the prior art, the invention aims to provide a method for treating low-grade scheelite, which enables tungsten in minerals to completely enter a solution, further separates and enriches the tungsten in the solution in a solvent extraction mode, realizes high-efficiency extraction of tungsten resources, provides a new way for resource utilization of the low-grade scheelite, overcomes the restriction of tungsten smelting on the ore dressing process, and greatly improves the comprehensive recovery rate of tungsten in the dressing process.

In order to achieve the technical purpose, the invention adopts the following technical scheme:

a method for processing low-grade scheelite comprises the following steps:

(1) adding the low-grade scheelite into dilute hydrochloric acid for acid washing, and performing solid-liquid separation to obtain acid washing slag and acid washing liquid;

(2) adding the acid washing slag into a hydrochloric acid-phosphoric acid mixed acid solution, and stirring and reacting at 70-95 ℃ for 1-5h to obtain a mixed acid decomposition liquid;

(3) adding concentrated sulfuric acid into the mixed acid decomposition liquid obtained in the step (2) for reaction, stirring for 5min, and filtering to obtain high-purity gypsum residue and filtrate; extracting tungsten in the filtrate by using a TBP extraction system to obtain a loaded organic phase and raffinate, and returning the raffinate to the step (2) for reuse after supplementing phosphoric acid and hydrochloric acid; and (3) carrying out back extraction on the loaded organic phase by using ammonia water to obtain a crude ammonium tungstate solution for the subsequent APT production.

Further, in the step (1), WO is contained in the low-grade scheelite₃The content is 15-40 wt%.

Further, in the step (1), the liquid-solid ratio of the low-grade scheelite to the dilute hydrochloric acid is 1-5mL/g, and the concentration of the dilute hydrochloric acid is 10-50 g/L.

Further, in the step (1), the acid washing process comprises the following steps: stirring and reacting for 10-30 min at room temperature.

Further, in the step (2), the liquid-solid ratio of the acid washing slag to the hydrochloric acid-phosphoric acid mixed acid is 1-5 mL/g.

Furthermore, in the hydrochloric acid-phosphoric acid mixed acid, the concentration of the hydrochloric acid is 50-150g/L, and the concentration of the phosphoric acid is 20-100 g/L.

Further, in the step (3), the concentrated sulfuric acid is adjusted according to Ca in the mixed acid decomposition solution²⁺And H₂SO₄In a molar ratio of 1: 0.95-1 of the additive.

Further, in the step (3), the TBP extraction system is a mixed system of TBP with the volume fraction of 40-80% and kerosene with the volume fraction of 20-60%, the extraction ratio is 1:1-2, and the mixing time is 5-10 min.

The invention has the advantages that:

the invention realizes the high-efficiency leaching of the low-grade scheelite, and the slag contains WO₃Can be reduced to below 0.5 wt%, overcomes the restriction of tungsten smelting on the mineral separation process, provides a feasible way for the development and utilization of low-grade scheelite, and greatly improves the comprehensive recovery rate of tungsten in the dressing and smelting process.

Detailed Description

In order to explain the present invention in more detail, the following examples are given for illustration, but the present invention is not limited to these examples.

Example 1

(1) Mixing WO at the ratio of 1:1(mL/g) to solid₃Adding 40 wt% of scheelite into 10g/L of dilute hydrochloric acid for acid washing, stirring at room temperature for 10min for reaction, and filtering to obtain acid washing slag and acid washing solution;

(2) adding acid-washing residue into mixed acid with hydrochloric acid concentration of 100g/L and phosphoric acid concentration of 100g/L according to liquid-solid ratio of 3:1(mL/g), stirring at 95 deg.C for 1h, filtering to obtain decomposition residue and mixed acid decomposition solution, and adding WO into the decomposition residue₃The content is 0.24 wt%;

(3) according to the molar ratio Ca in the mixed acid decomposition liquid²⁺:H₂SO₄Adding concentrated sulfuric acid into the mixed acid decomposition liquid according to the proportion of 1:0.95, stirring for 5min, and filtering to obtain high-purity gypsum (the purity is 99.5 wt%) and filtrate; under the condition of a ratio of 1:1, mixing a kerosene system with a volume fraction of 50% TBP-50% with the filtrate at room temperature for 10min, wherein the extraction rate of tungsten is 99.1%, and returning raffinate to be used for mixed acid decomposition of acid washing slag after supplementing hydrochloric acid and phosphoric acid; then 15 percent of dilute ammonia water is used for carrying out back extraction on the loaded organic phase, and the back extraction rate of tungsten is 99.5 percentAnd the obtained crude ammonium tungstate solution is used for the subsequent APT production.

Example 2

(1) Mixing WO at the ratio of 2:1(mL/g) to obtain a mixture₃Adding 20 wt% of scheelite into 30g/L of dilute hydrochloric acid for acid washing, stirring at room temperature for reaction for 30min, and filtering to obtain acid washing slag and acid washing solution;

(2) adding the filter residue into mixed acid with hydrochloric acid concentration of 50g/L and phosphoric acid concentration of 100g/L according to liquid-solid ratio of 2:1(mL/g), stirring at 70 deg.C for reaction for 5 hr, filtering to obtain decomposed residue and mixed acid decomposed solution, and adding WO into the decomposed residue₃The content is 0.37 wt%;

(3) according to the molar ratio Ca in the mixed acid decomposition liquid²⁺:H₂SO₄Adding concentrated sulfuric acid into the mixed acid decomposition liquid according to the proportion of 1:1, stirring for 5min, and filtering to obtain high-purity gypsum (the purity is 99.4 wt%) and filtrate; under the condition of a ratio of 1:1, mixing a kerosene system with the volume fraction of 40% TBP-60% with the filtrate at room temperature for 5min, wherein the extraction rate of tungsten is 99.3%, and returning raffinate to be used for mixed acid decomposition of acid washing slag after supplementing hydrochloric acid and phosphoric acid; and then carrying out back extraction on the loaded organic phase by using 15% dilute ammonia water, wherein the back extraction rate of tungsten is 99.4%, and the obtained crude ammonium tungstate solution is used for the subsequent APT production.

Example 3

(1) Mixing WO at the ratio of 1:1(mL/g) to solid₃Adding 15 wt% of scheelite into 50g/L of dilute hydrochloric acid for acid washing, stirring at room temperature for reaction for 30min, and filtering to obtain acid washing slag and acid washing solution;

(2) adding the filter residue into mixed acid with hydrochloric acid concentration of 100g/L and phosphoric acid concentration of 20g/L according to liquid-solid ratio of 1:1(mL/g), stirring at 80 deg.C for reaction for 3 hr, filtering to obtain decomposition residue and mixed acid decomposition solution, and adding WO into the decomposition residue₃The content is 0.42 wt%;

(3) according to the molar ratio Ca in the mixed acid decomposition liquid²⁺:H₂SO₄Adding concentrated sulfuric acid into the mixed acid decomposition liquid according to the proportion of 1:1, stirring for 5min, and filtering to obtain high-purity gypsum (the purity is 99.3 wt%) and filtrate; under the condition of comparison of 1:1, a kerosene system with the volume fraction of 80 percent TBP-20 percent is used for filtering at room temperatureMixing the solution for 5min, wherein the extraction rate of tungsten is 99.5%, and the raffinate is supplemented with hydrochloric acid and phosphoric acid and then returned to be used for mixed acid decomposition of acid washing slag; and then carrying out back extraction on the loaded organic phase by using 15% dilute ammonia water, wherein the back extraction rate of tungsten is 99.6%, and the obtained crude ammonium tungstate solution is used for the subsequent APT production.

Example 4

(1) Mixing WO at the ratio of 2:1(mL/g) to obtain a mixture₃Adding 25 wt% of scheelite into 30g/L of dilute hydrochloric acid for acid washing, stirring at room temperature for reaction for 10min, and filtering to obtain acid washing slag and acid washing solution;

(2) adding the filter residue into mixed acid with hydrochloric acid concentration of 50g/L and phosphoric acid concentration of 50g/L according to liquid-solid ratio of 1:1(mL/g), stirring at 80 deg.C for 2 hr, filtering to obtain decomposed residue and mixed acid decomposed solution, and adding WO into the decomposed residue₃The content is 0.36 wt%;

(3) according to the molar ratio Ca in the mixed acid decomposition liquid²⁺:H₂SO₄Adding concentrated sulfuric acid into the mixed acid decomposition liquid according to the proportion of 1:0.95, stirring for 5min, and filtering to obtain high-purity gypsum (the purity is 99.4 wt%) and filtrate; under the condition of a ratio of 1:1, mixing a kerosene system with a volume fraction of 50% TBP-50% with the filtrate at room temperature for 6min, wherein the extraction rate of tungsten is 99.4%, and returning raffinate to be used for mixed acid decomposition of acid washing slag after supplementing hydrochloric acid and phosphoric acid; and then carrying out back extraction on the loaded organic phase by using 15% dilute ammonia water, wherein the back extraction rate of tungsten is 99.5%, and the obtained crude ammonium tungstate solution is used for the subsequent APT production.