Bismuth removal agent for deeply removing bismuth from solution and purification method of bismuth removal agent

Abstract

The invention relates to a bismuth removal agent for deeply removing bismuth from a solution and a purification method of the bismuth removal agent, and belongs to the technical field of hydrometallurgy processes. The method comprises the following steps: adding lead tetrafluoride as a bismuth removal agent into a solution to be purified, reacting under the conditions of set temperature and stirring, standing and settling after the reaction is finished, and carrying out liquid-solid separation, so as to obtain a bismuth-removed solution and bismuth-removed slag. Wherein the adding amount of the lead tetrafluoride is 1: 1-100: 1 based on the molar ratio of lead to bismuth. The method is suitable for acidic or neutral solutions, in particular for electrolytes for metal electrorefining or electrodeposition. The purification method has the advantages of simple process, good removal effect, high purification efficiency and no introduction of new impurities.

Description

Technical Field

[0001] This application relates to the field of hydrometallurgical process technology, and in particular to a bismuth removal agent for deep removal of bismuth from solution and a purification method thereof. Background Technology

[0002] In the preparation of high-purity antimony, copper, lead, zinc, and other metals, bismuth, as a co-existing impurity, is a key element affecting product purity. Industrially, these metals are often extracted using electrolytic refining or electrolytic deposition methods, but the removal of bismuth is a core challenge in these processes.

[0003] During electrolytic refining, anode dissolution introduces impurities into the electrolyte. Impurities with a significantly negative potential than the host metal remain in the electrolyte; those with a significantly positive potential settle as anode sludge; while impurities with potentials close to the host metal (such as bismuth) may co-deposit with the host metal at the cathode, directly contaminating the product. The preparation of fresh electrolyte during electrolytic deposition may also introduce trace impurities. Therefore, to obtain high-purity metals, a separate purification process is necessary to specifically remove these impurity ions with potentials close to or more positive than the host metal. Bismuth's deposition potential is similar to that of antimony, copper, and lead, and more positive than zinc, making it extremely difficult to completely separate during the electrolytic purification of these metals.

[0004] To obtain high-quality metal products, the development of a simple purification technology that can deeply remove bismuth is a continuous pursuit of those skilled in the art. Summary of the Invention

[0005] To address or partially address the problems existing in related technologies, this application provides a bismuth removal agent and a purification method for deep removal of bismuth from solution. The purification method for deep removal of bismuth from solution in this application involves adding lead tetrafluoride as a bismuth removal agent to the solution to be purified, carrying out a removal reaction under set temperature and stirring conditions, stopping stirring after the reaction is completed and allowing it to settle, and then separating the liquid and solid to obtain a bismuth-removed liquid and a bismuth-removed residue. The amount of bismuth removal agent added is 1:1 to 100:1, calculated based on the molar ratio of lead in lead tetrafluoride to bismuth in the solution to be purified.

[0006] Furthermore, the solution to be purified is a chloride system electrolyte for preparing high-purity antimony through electrolytic refining of refined antimony, an antimony tartrate system electrolyte for preparing high-purity antimony, an electrolyte for preparing crude antimony through electrolytic refining of lead-antimony alloy, or a copper sulfate system electrolyte for preparing cathode copper through electrolytic refining of crude copper. Furthermore, the impurity removal reaction is specifically carried out at a temperature of 25℃-95℃ and a stirring speed of 400~800 rpm for 1-12 h.

[0007] Furthermore, the settling time is 1-6 hours.

[0008] Furthermore, the liquid-solid separation is carried out by plate and frame filtration or centrifugal filtration, and the filter cloth used has a mesh size of 400 to 500 mesh.

[0009] This application also provides a bismuth removal agent for deep removal of bismuth from solution, said bismuth removal agent being lead tetrafluoride, and used in any of the methods described above.

[0010] The mechanism of deep bismuth removal using lead tetrafluoride in this application is as follows: Lead tetrafluoride is insoluble in neutral or acidic solutions, and the tetravalent lead ions in lead tetrafluoride adsorb and reduce bismuth ions in the solution, thus forming a water-insoluble complex lead-bismuth fluoride.

[0011] The beneficial effects of this application are: the purification method provided has the advantages of simple process, easy operation, good impurity removal effect, high purification efficiency and no introduction of new impurities into the solution to be treated. Detailed Implementation

[0012] The embodiments of this application will now be described in more detail with reference to the examples. While embodiments of this application are shown in the examples, it should be understood that this application can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art. Example 1

[0013] This embodiment provides a method for deep removal of bismuth from the electrolyte of antimony electrolytic refining, the specific steps of which are as follows: (1) Take the sulfuric acid-ammonium fluoride-antimony fluoride electrolyte to be purified, wherein the sulfuric acid concentration is 300 g / L, the antimony ion concentration is 100 g / L, the fluoride ion concentration is 80 g / L, and the ammonium ion concentration is 50 g / L. The bismuth content in the electrolyte is 18.20 mg / L.

[0014] (2) Preparation and addition of bismuth removal agent: Measure 200L of the above-mentioned bismuth-containing antimony electrolyte. The total molar amount of bismuth contained therein is calculated to be 17.42 mmol. Based on the molar ratio of lead (Pb) in lead tetrafluoride to bismuth (Bi) in the solution being 1:1, weigh the corresponding mass of lead tetrafluoride. Place the weighed lead tetrafluoride into the purification tank.

[0015] (3) Purification reaction: 200 L of bismuth-containing antimony electrolyte was pumped into the purification tank at a flow rate of 20 L / min and mixed with lead tetrafluoride. The stirring was turned on and the temperature of the reaction system was controlled at 45℃. The reaction was continued for 3 hours at a stirring speed of 500 rpm (the timer started from the time the bismuth-containing antimony electrolyte was pumped in, the same below). After the reaction was completed, the stirring was stopped and the mixture was allowed to stand for 3 hours to allow the solid material to settle completely.

[0016] (4) Liquid-solid separation: All the mixed materials in the purification tank are discharged and separated by a plate and frame filter press equipped with 400 mesh filter cloth, and the solid residue and filtrate are collected separately.

[0017] Experimental results: The obtained filtrate (i.e., the bismuth-free liquid) was tested and the bismuth content was found to be 0.008 mg / L. Calculations show that the bismuth removal rate exceeded 99.95%, achieving deep purification. Example 2

[0018] This embodiment provides a method for deep removal of bismuth from the electrolyte in the electrolytic refining of lead-antimony alloys. The specific steps are as follows: (1) Take the lead-antimony alloy electrolyte to be purified. After testing, the bismuth content is 15.42 mg / L.

[0019] (2) Preparation and addition of bismuth removal agent: Measure 200 L of the above-mentioned bismuth-containing electrolyte. The total molar amount of bismuth contained therein is calculated to be 14.76 mmol. Based on the molar ratio of lead (Pb) in lead tetrafluoride to bismuth (Bi) in the solution being 5:1, weigh the corresponding mass of lead tetrafluoride. Place the weighed lead tetrafluoride into the purification tank.

[0020] (3) Purification reaction: 200 L of bismuth-containing electrolyte was pumped into the purification tank at a flow rate of 20 L / min and mixed with lead tetrafluoride. The stirring was turned on and the temperature of the reaction system was controlled at 45℃. The reaction was continued for 3 h at a stirring speed of 500 rpm. After the reaction was completed, the stirring was stopped and the mixture was allowed to stand for 3 h to allow the solid material to settle completely.

[0021] (4) Liquid-solid separation: All the mixed materials in the purification tank are discharged and separated by a plate and frame filter press equipped with 400 mesh filter cloth, and the solid residue and filtrate are collected separately.

[0022] Experimental results: The obtained filtrate (i.e., the bismuth-free liquid) was tested and the bismuth content was found to be 0.004 mg / L. Calculations show that the bismuth removal rate exceeded 99.97%, achieving deep purification. Example 3

[0023] This embodiment provides a method for deep removal of bismuth from copper sulfate solution, the specific steps of which are as follows: (1) Take a sample of the copper sulfate solution to be purified. The bismuth content was found to be 1.269 mg / L.

[0024] (2) Preparation and addition of bismuth removal agent: Measure 120 L of the above-mentioned bismuth-containing copper sulfate solution. The total molar amount of bismuth contained therein is calculated to be 0.73 mmol. Based on the molar ratio of lead (Pb) in lead tetrafluoride to bismuth (Bi) in the solution being 15:1, weigh the corresponding mass of lead tetrafluoride. Place the weighed lead tetrafluoride into the purification tank.

[0025] (3) Purification reaction: 120 L of bismuth-containing copper sulfate solution was pumped into the purification tank at a flow rate of 30 L / min and mixed with lead tetrafluoride. The stirring was turned on and the temperature of the reaction system was controlled at 55℃. The reaction was continued for 6 h at a stirring speed of 400 rpm. After the reaction was completed, the stirring was stopped and the mixture was allowed to stand for 2 h to allow the solid material to settle completely.

[0026] (4) Liquid-solid separation: All the mixed materials in the purification tank are discharged and separated by a plate and frame filter press equipped with 400 mesh filter cloth, and the solid residue and filtrate are collected separately.

[0027] Experimental results: The obtained filtrate (i.e., the bismuth-free liquid) was tested and the bismuth content was found to be 0.007 mg / L. Calculations show that the bismuth removal rate reached 99.45%, achieving deep purification. Example 4

[0028] This embodiment provides a method for deep removal of bismuth from the antimony tartrate electrolyte system used to prepare high-purity antimony. The specific steps are as follows: (1): The electrolyte sample of the antimony tartrate system to be purified was tested and found to contain 0.173 mg / L of bismuth.

[0029] (2) Preparation and addition of bismuth removal agent: Measure 100 L of the above-mentioned bismuth-containing electrolyte. The total molar amount of bismuth contained therein is calculated to be 0.083 mmol. Based on the molar ratio of lead (Pb) in lead tetrafluoride to bismuth (Bi) in the solution being 10:1, weigh the corresponding mass of lead tetrafluoride. Place the weighed lead tetrafluoride into the purification tank.

[0030] (3) Purification reaction: 100 L of bismuth-containing electrolyte was pumped into the purification tank at a flow rate of 30 L / min and mixed with lead tetrafluoride. The stirring was turned on and the temperature of the reaction system was controlled at 55℃. The reaction was continued for 6 h at a stirring speed of 400 rpm. After the reaction was completed, the stirring was stopped and the mixture was allowed to stand for 2 h to allow the solid material to settle completely.

[0031] (4) Liquid-solid separation: All the mixed materials in the purification tank are discharged and separated by a plate and frame filter press equipped with 500 mesh filter cloth, and the solid residue and filtrate are collected separately.

[0032] Experimental results: The obtained filtrate (i.e., the bismuth-free liquid) was tested and the bismuth content was found to be 0.001 mg / L. Calculations show that the bismuth removal rate reached 99.42%, achieving deep purification. Example 5

[0033] This embodiment provides a method for deep removal of bismuth from the chloride system electrolyte of antimony electrolytic refining, and the specific steps are as follows: (1) A sample of the chloride system electrolyte to be purified was taken and tested. The bismuth content was 0.249 mg / L.

[0034] (2) Preparation and addition of bismuth removal agent: Measure 150 L of the above-mentioned bismuth-containing electrolyte. The total molar amount of bismuth contained therein is calculated to be 0.179 mmol. Based on the molar ratio of lead (Pb) in lead tetrafluoride to bismuth (Bi) in the solution being 50:1, weigh the corresponding mass of lead tetrafluoride. Place the weighed lead tetrafluoride into the purification tank.

[0035] (3) Purification reaction: 150 L of bismuth-containing electrolyte was pumped into the purification tank at a flow rate of 50 L / min and mixed with lead tetrafluoride. The stirring was turned on and the temperature of the reaction system was controlled at 75℃. The reaction was continued for 2 h at a stirring speed of 500 rpm. After the reaction was completed, the stirring was stopped and the mixture was allowed to stand for 1 h to allow the solid material to settle completely.

[0036] (4) Liquid-solid separation: All the mixed materials in the purification tank are discharged and separated by a plate and frame filter press equipped with 500 mesh filter cloth, and the solid residue and filtrate are collected separately.

[0037] Experimental results: The obtained filtrate (i.e., the bismuth-free liquid) was tested and the bismuth content was found to be 0.002 mg / L. Calculations show that the bismuth removal rate reached 99.20%, achieving deep purification. Example 6

[0038] This embodiment demonstrates the enhanced purification effect of the method under the same electrolyte system and with higher impurity concentrations by optimizing the combination of bismuth removal agents and separation conditions. The specific steps are as follows: (1) Take a sample of the lead-antimony alloy electrolytic refining electrolyte to be purified (the same system as in Example 1). The bismuth content was found to be 20.62 mg / L, which is a relatively high initial concentration.

[0039] (2) Preparation and addition of bismuth removal agent: 80 L of the above high-concentration bismuth-containing electrolyte was measured. The total molar amount of bismuth contained therein was calculated to be 7.89 mmol. In order to cope with higher impurity load, the corresponding mass of lead tetrafluoride was weighed according to the molar ratio of lead (Pb) to bismuth (Bi) in lead tetrafluoride being 100:1, and placed in the purification tank.

[0040] (3) Purification reaction: 80 L of electrolyte was pumped into the purification tank at a flow rate of 20 L / min and mixed with lead tetrafluoride. The stirring was turned on and the temperature of the reaction system was controlled at 55℃. The reaction was continued for 4 h at a stirring speed of 500 rpm. After the reaction was completed, the stirring was stopped and the mixture was allowed to stand for 2 h to promote solid phase coagulation and sedimentation.

[0041] (4) Liquid-solid separation: All materials in the purification tank are discharged and a filtration device equipped with a 600-mesh (higher than the aforementioned embodiment) filter cloth is used for precision liquid-solid separation, and the bismuth removal residue and filtrate are collected separately.

[0042] Experimental results: The obtained filtrate (i.e., the bismuth-free liquid) was tested and found to contain 0.007 mg / L of bismuth. Calculations show that even with a higher initial concentration, the bismuth removal rate still reached 99.97%, achieving highly efficient deep purification.

[0043] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A purification method for deep removal of bismuth from solution, characterized in that: Lead tetrafluoride was added to the solution to be purified, and a purification reaction was carried out under set temperature and stirring conditions. After the reaction was completed, stirring was stopped and the solution was allowed to settle. After liquid-solid separation, bismuth-removed liquid and bismuth-removed residue were obtained. The amount of lead tetrafluoride added is calculated as 1:1 to 100:1, based on the molar ratio of lead in lead tetrafluoride to bismuth in the solution to be purified.

2. The purification method for deep removal of bismuth from solution according to claim 1, characterized in that, The solution to be purified is a chloride system electrolyte for preparing high-purity antimony through electrolytic refining of refined antimony, an antimony tartrate system electrolyte for preparing high-purity antimony, an electrolyte for preparing crude antimony through electrolytic refining of lead-antimony alloys, or a copper sulfate system electrolyte for preparing cathode copper through electrolytic refining of crude copper.

3. A purification method for deep removal of bismuth from solution according to claim 1, characterized in that, The impurity removal reaction is specifically carried out at a temperature of 25℃-95℃ and a stirring speed of 400~800 rpm for 1-12 h.

4. A purification method for deep removal of bismuth from solution according to claim 1, characterized in that, The settling time is 1-6 hours.

5. The purification method for deep removal of bismuth from solution according to claim 1, characterized in that, The liquid-solid separation is carried out by plate and frame filtration or centrifugal filtration, and the filter cloth used has a mesh size of 400 to 500 mesh.

6. A bismuth removal agent for deep removal of bismuth from solution, characterized in that, The bismuth removal agent is lead tetrafluoride and is used in the method of any one of claims 1-5.