Method for recovering precious metal from precious antimony and preparing sodium pyroantimonate

Abstract

The invention discloses a method for recovering precious metal from precious antimony and preparing sodium pyroantimonate. The method comprises two steps of precious antimony anode electrochemical oxidation and sodium antimonite electrolyte enhanced oxidation for preparing sodium pyroantimonate. According to the method provided by the invention, through electrochemical oxidation of a precious antimony anode, precious antimony is taken as the anode, a sodium hydroxide solution is taken as an electrolyte, antimony is converted into a sodium antimonite electrolyte through discharging of the precious antimony at the anode, and precious metals in the precious antimony are enriched and recovered in the form of anode mud. And the sodium antimonite electrolyte is converted into a sodium pyroantimonite product in a shear enhanced oxidation manner. Compared with the existing soot blowing and other processes for precious antimony treatment, the method provided by the invention has the advantages of low temperature, better precious metal enrichment effect, high product added value and the like, and has very good industrial application value.

Description

Technical Field

[0001] The invention belongs to the field of metallurgy and chemical industry, and in particular relates to a method for recovering precious metals from precious antimony and preparing sodium pyroantimonate. Background Art

[0002] Precious antimony is a crude antimony alloy containing precious metals such as gold and silver that is deposited on the bottom of the furnace during the volatilization of stibnite containing precious metals in a blast furnace and the reduction smelting process in a reverberatory furnace. It usually contains 100~3000 g / t of gold and 300~5000 g / t of silver, and is of great recycling value. At present, precious antimony is mainly treated in an ash-blowing furnace. By passing air into the precious antimony at high temperature, the antimony is oxidized to antimony oxide and volatilized and collected, while the precious metals are retained in the ash-blowing bottom water for enrichment. The ash-blowing process has high energy consumption and high pollution. Some precious metals are dispersed in the ash, and the enrichment efficiency of precious metals is low. The precious metal content in the obtained rich antimony is usually about 10~20 kg / t. It also needs to be further oxidized and leached through a wet leaching process to finally achieve the recovery of precious metals.

[0003] The rapid development of the photovoltaic industry in recent years has led to an increasing demand for high-transmittance glass. Sodium pyroantimonate is a commonly used clarifier for the preparation of high-transmittance glass. As the demand for photovoltaic glass increases, the preparation of antimony into sodium pyroantimonate has become the focus of the antimony smelting industry. At present, the preparation of sodium pyroantimonate mainly uses antimony oxide as a raw material, which is reacted with sodium hydroxide solution to convert it into sodium antimonite solution, and then an oxidant is added to it to finally obtain the sodium pyroantimonate product. However, the oxidation efficiency of the existing sodium pyroantimonate oxidation process is low, and part of the antimony still exists in the form of sodium antimonite. It is difficult for the product quality to stably meet the requirements of the sodium pyroantimonate industry standard (YS / T22-2010). Summary of the invention

[0004] In order to solve the problems of high energy consumption, low efficiency of precious metal enrichment, low added value of antimony and a series of inadequacies in the prior art precious antimony treatment process, the present invention aims to provide a method for recovering precious metals from precious antimony and preparing sodium pyroantimonate. The method of the present invention adopts a new process for preparing sodium pyroantimonate by electrochemical oxidation dissolution of precious antimony-sodium antimonite shear strengthening. Compared with the existing precious antimony treatment technology, the process has the advantages of low treatment temperature and high efficiency of precious metal enrichment. In addition, the present invention proposes a method for preparing sodium pyroantimonate by shear strengthening of sodium antimonite, which greatly improves the oxidation efficiency of sodium antimonite. At the same time, the closed-loop circulation of the solution in this technology can effectively avoid the discharge of wastewater, the process is clean and environmentally friendly, and has good industrial application prospects in the treatment of precious antimony and rich antimony.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The invention provides a method for recovering precious metals from precious antimony and preparing sodium pyroantimonate. Precious antimony is melted and cast into an anode, which is placed in an electrolytic cell. Sodium hydroxide solution is used as an electrolyte to obtain a solution containing sodium antimonite and anode mud enriched with precious metals through electrochemical oxidation and dissolution. An oxidant is added to the solution containing sodium antimonite, and sodium pyroantimonate is obtained by shear-strengthening the oxidation of sodium antimonite.

[0007] The method provided by the present invention combines electrochemical oxidation technology with mechanical strengthening oxidation technology, uses noble antimony as an anode, and uses sodium hydroxide as an electrolyte. Under a certain current intensity, the antimony in the noble antimony is oxidized and dissolved at the anode and converted into sodium antimonite, which is dissolved in the electrolyte to form a solution containing sodium antimonite, while the precious metals such as gold and silver in the noble antimony are not dissolved, so they fall from the anode and are converted into anode mud, which is separated from the electrolytic solution after filtration; since the antimony in the noble antimony is basically dissolved during electrolysis, the gold and silver grades in the obtained anode mud are high, and gold and silver can be directly extracted as raw materials. For the solution containing sodium antimonite, the shear strengthening method is adopted to improve the oxidation conversion efficiency of sodium antimonite, while reducing the amount of oxidant, the production efficiency is also improved, and the stable compliance of the sodium pyroantimonate product is achieved.

[0008] According to a preferred embodiment, the noble antimony has an antimony content of ≥97.0%, an arsenic content of <0.5%, a lead content of <0.5%, an iron content of <0.5%, a precious metal gold content of 1-50,000 g / t, and a silver content of 1-50,000 g / t.

[0009] The inventors found that when the arsenic content in precious antimony is higher than 0.5%, the arsenic and lead contents in the sodium pyroantimonate product will exceed the industry standard (YS / T22-2010) after diaphragm electrolysis and oxidation precipitation using the precious antimony as the anode. The sodium pyroantimonate product is difficult to meet the requirements; when the iron content is higher than 0.5%, the iron will be oxidized together with the precious antimony during the electrochemical oxidation process to form Fe(OH) 3 Slag, Fe(OH) 3 It is a slag that is difficult to decouple and wash, and it adsorbs a large amount of antimony ions, resulting in a decrease in the direct recovery of antimony. In addition, Fe(OH) 3 The slag is also difficult to separate from the anode mud, resulting in difficulty in recovering precious metals. In addition, during the electrochemical dissolution of precious antimony, if the lead content is higher than 0.5%, some of the lead will also precipitate in the anode mud and require further treatment. Some of the lead will also react with OH -Coordinated into the electrolyte, and together into the sodium pyroantimonate product, making it difficult for the sodium pyroantimonate product to meet the national standard requirements. Therefore, the new process for producing sodium pyroantimonate and recovering precious metals from precious antimony proposed in the present invention is adopted to ensure that the quality of the sodium pyroantimonate product meets the national standard requirements, and the grade of the gold and silver precious metals enriched in the anode mud is as high as possible, preferably the grade of precious antimony is greater than 97.0%, the arsenic content is less than 0.5%, the lead content is less than 0.5%, and the iron content is less than 0.5%. If the antimony grade is insufficient or the above impurity content exceeds the standard, it is necessary to first use the impurity removal and refining method to pre-remove impurity elements such as arsenic, lead, and iron from the precious antimony, so that the precious antimony meets the requirements of arsenic content less than 0.5%, lead content less than 0.5%, and iron content less than 0.5%.

[0010] In a preferred embodiment, the electrolytic cell comprises an anode chamber, a cathode chamber and a cation exchange membrane; wherein the cation exchange membrane separates the anode chamber from the cathode chamber.

[0011] In the present invention, a cation exchange membrane is required to separate the cathode chamber and the anode chamber during the electrochemical dissolution of noble antimony. The reason is that after the anode antimony is dissolved, antimonite (SbO 2 - ) exists in the form of. If there is no cation membrane to separate the cathode and anode, it will discharge on the cathode surface and turn into antimony powder precipitation. On the one hand, it is impossible to separate antimony from precious metals. On the other hand, antimony is reduced to antimony powder again. The use of cation exchange membrane can prevent the antimonite (SbO 2 - ) enters the cathode chamber to avoid the electrolytic deposition of antimony at the cathode, thereby obtaining a solution containing sodium antimonite.

[0012] Further preferably, the cation exchange membrane is one of a homogeneous ion exchange membrane, a semi-homogeneous ion exchange membrane and a heterogeneous ion exchange membrane.

[0013] Further preferably, the anode chamber accommodates an anode, the cathode chamber accommodates a cathode, and the electrolyte is distributed in the anode chamber and the cathode chamber.

[0014] In a preferred embodiment, the cathode used for the electrochemical oxidation dissolution is selected from a stainless steel plate, a graphite plate, and a titanium plate.

[0015] Preferably, the concentration of the sodium hydroxide solution is 40-200 g / L, more preferably 120-160 g / L.

[0016] In a preferred embodiment, the temperature during the electrochemical oxidation dissolution is 30 to 80°C, more preferably 40 to 60°C, and the anode current density is 50 to 400 A / m 2 , more preferably 150~250 A / m 2 .

[0017] According to a preferred embodiment, after the electrochemical oxidation dissolution is completed, the electrolytic cell and the anode residue are rinsed with clean water, the obtained washing water is combined with the electrolyte and then the solid-liquid separation is carried out. The obtained liquid phase is a solution containing sodium antimonite, and the obtained solid phase is anode mud enriched with precious metals.

[0018] In the present invention, completion of electrochemical oxidation dissolution means completion of production within a certain period of time, and the amount of sodium pyroantimonate obtained is obtained by dissolving the anode within a certain period of time, which does not mean that the anode is completely dissolved. As the anode dissolves, the amount of dissolution gradually increases with the extension of time.

[0019] Further preferably, the obtained anode mud enriched with precious metals is sent to a precious metal workshop to extract the precious metals.

[0020] In a preferred embodiment, the oxidant is selected from one or more of air, oxygen, ozone, hydrogen peroxide, and sodium hypochlorite, and the amount of the oxidant is 0.8 to 1.0 times the theoretical amount of sodium pyroantimonate to oxidize sodium antimonite.

[0021] In the present invention, it is necessary to control the amount of the oxidant to be slightly lower than or equal to the theoretical amount. 2 O 2 When the amount used exceeds the theoretical amount of sodium antimonite required to prepare sodium pyroantimonate, the excess H 2 O 2 The electrolyte is returned to the noble antimony electrochemical dissolution process to convert the antimony into soluble SbO 2 - When further transformed into insoluble NaSbO 3 , and attached to the surface of the noble antimony anode, causing anodization, which made the electrochemical dissolution of the noble antimony unable to continue. In order to ensure that the electrolyte after preparing sodium pyroantimonate can be recycled, H 2 O 2 The amount used should not be higher than the theoretical amount required for preparing sodium pyroantimonate from sodium antimonite.

[0022] Preferably, the shear rate of the shear enhanced oxidation is 1000-10000 r / min, more preferably 2000-5000 r / min.

[0023] In the present invention, the shear strengthening process can effectively improve the oxidation effect of sodium antimonite, improve the yield and product quality of sodium pyroantimonate, and when air is used as an oxidant, if the shear strengthening technology is not used, the oxidation rate of sodium antimonite can only reach 60-70%, while after the shear strengthening technology is used, the oxidation rate of sodium antimonite can reach 90-98%, and the oxidation efficiency is greatly improved.

[0024] Preferably, the shearing form of the shear-enhanced oxidation is internal shearing or external shearing, or a combination of both.

[0025] Preferably, the temperature of the shear enhanced oxidation is 40-98°C and the time is 2-6h.

[0026] According to a preferred embodiment, an oxidant is added to a solution containing sodium antimonite, sodium antimonite is oxidized by shear-enhanced oxidation to obtain a solution containing sodium pyroantimonate, the solid-liquid is separated, and the obtained solid phase is dried to obtain sodium pyroantimonate. The obtained liquid phase is supplemented with sodium hydroxide and then returned as an electrolyte for the electrochemical oxidation and dissolution of the next batch of precious antimony.

[0027] Further preferably, the molar amount of the supplemented sodium hydroxide is equal to the molar amount of the solid-liquid separation sodium pyroantimonate.

[0028] Principles and advantages

[0029] The present invention provides a method for recovering precious metals from precious antimony and preparing sodium pyroantimonate, which combines electrochemical oxidation technology with mechanical enhanced oxidation technology, uses precious antimony as an anode, and uses sodium hydroxide as an electrolyte. Under a certain current intensity, the antimony in the precious antimony is oxidized and dissolved at the anode and converted into sodium antimonite, which is dissolved in the electrolyte to form a solution containing sodium antimonite, while the precious metals such as gold and silver in the precious antimony do not dissolve, and thus fall from the anode to become anode mud, which is separated from the anode liquid after filtration; since the antimony in the precious antimony is basically dissolved during electrolysis, the gold and silver grades in the obtained anode mud are high, and gold and silver can be directly extracted as raw materials. For the solution containing sodium antimonite, the shear enhancement method is adopted to improve the oxidation conversion efficiency of sodium antimonite, while reducing the amount of oxidant, the production efficiency is also improved, and the sodium pyroantimonate product can be stably up to standard.

[0030] Compared with the prior art, the present invention has at least the following advantages:

[0031] (1) Innovative use of alkaline cationic diaphragm electrolysis system to electrolyze precious antimony, directly prepare sodium antimonate and efficiently enrich precious metals. The enriched gold and silver content is increased by a thousand times compared to the raw material content, avoiding the problems of high energy consumption, long process, heavy pollution and precious metal dispersion in the current pyrometallurgical ash blowing treatment of precious antimony.

[0032] (2) The present invention controls the contents of main elements such as antimony, arsenic, lead, and iron in the noble antimony anode to meet specific content requirements (antimony content is higher than 97.0%, arsenic content is lower than 0.5%, lead content is lower than 0.5%, and iron content is lower than 0.5%), and performs diaphragm electrolysis. After the obtained anode liquid is oxidized and precipitated, a sodium pyroantimonate product that meets the national quality requirements can be directly obtained. This avoids the disadvantage that the conventional method requires repeated purification of the sodium antimonite solution before a qualified sodium pyroantimonate product can be prepared. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The invention discloses a process for recovering precious metals from precious antimony and preparing sodium pyroantimonate.

[0034] Figure 2 This is a schematic diagram of the electrochemical dissolution device for precious antimony according to the present invention; in the figure, 1: precious antimony; 2: DC power supply; 3: cation exchange membrane; 4: NaOH electrolyte; 5: cathode.

[0035] Figure 3 This is the XRD of the sodium pyroantimonate product obtained by the present invention. DETAILED DESCRIPTION

[0036] The following examples are intended to further illustrate the present invention, but are not intended to limit the present invention.

[0037] Example 1

[0038] Step 1: 150 kg of noble antimony with a composition of 99.98% antimony, 0.03% arsenic, 0.04% lead, 0.01% iron, 142.16 g / t gold, and 287.47 g / t silver was melted and cast into an anode of 70×80×4 cm. At the same time, a stainless steel plate of 70×80×0.5 cm was used as the cathode, and the anode and cathode were placed in a homogeneous cationic membrane electrolyzer. The electrolyte was 100 L of NaOH with a concentration of 120 g / L, which was evenly distributed in the cathode chamber and the anode chamber, at a temperature of 60 °C and a current of 250 A / m 2 The current density was energized for 10 h to carry out the electrochemical dissolution process of precious antimony. The cell voltage was about 1.21 V during the electrolysis process. After the power was turned on, the antimony concentration in the electrolyte in the anode chamber was 41.16 g / L. At the same time, the electrolytes in the cathode chamber and the anode chamber were mixed and filtered. After filtration, 6.58 g of anode mud was obtained, of which the gold content was 4.58% and the silver content was 9.26%. The obtained anode mud was filtered and dried and sent to the precious metal workshop for treatment.

[0039] Step 2: At a temperature of 45 °C and a shear speed of 3000 r / min, 1.95 kg of 30% H 2 O 2 (0.99 times the theoretical amount) was slowly added to the antimony-containing solution obtained in step 1 within 3 hours. After the reaction was completed, 3.14 kg of sodium pyroantimonate was obtained by filtration and drying. 2 O 2 The oxidation rate reaches 97.36%. The arsenic content of sodium pyroantimonate products is 0.002%, the lead content is 0.003%, and the iron content is 0.001%, meeting the quality requirements of first-class products of YS / T 22-2010.

[0040] Example 2

[0041] Step 1: 150 kg of noble antimony with a composition of 99.98% antimony, 0.03% arsenic, 0.04% lead, 0.01% iron, 142.16 g / t gold, and 287.47 g / t silver was melted and cast into an anode of 70×80×4 cm. At the same time, a stainless steel plate of 70×80×0.5 cm was used as the cathode plate, and the anode and cathode were placed in a homogeneous cationic membrane electrolyzer. At a temperature of 40 °C, the electrolyte was 100 L of NaOH with a concentration of 160 g / L, which was evenly distributed in the cathode chamber and the anode chamber, and the electrolyte was heated at 100 A / m 2 The current density was energized for 48 h to carry out the electrochemical dissolution process of precious antimony. The cell voltage was about 1.65 V during the electrolysis process. After the power was turned on, the antimony concentration in the electrolyte was 80.02 g / L. At the same time, the electrolytes in the cathode chamber and the anode chamber were mixed and filtered. After filtration, 10.71 g of anode mud was obtained, of which the gold content was 5.41% and the silver content was 10.93%. The obtained anode mud was filtered and dried and sent to the precious metal workshop for treatment.

[0042] Step 2: At a temperature of 50 °C and a shear speed of 6000 r / min, 3 Pure oxygen (0.80 times the theoretical amount) was slowly introduced into the antimony-containing solution obtained in step 1 over 4 hours. After the reaction was completed, 4.98 kg of sodium pyroantimonate was obtained by filtration and drying. 2 O 2 The utilization rate reaches 98.29%. The arsenic content of sodium pyroantimonate products is 0.002%, the lead content is 0.001%, and the iron content is 0.001%, meeting the quality requirements of first-class products in YS / T 22-2010.

[0043] Example 3

[0044] Step 1: 150 kg of noble antimony containing 99.99% antimony, 0.02% arsenic, 0.03% lead, 0.04% iron, 142.16 g / t gold, and 287.47 g / t silver is melted and cast into an anode of 70×80×4 cm. At the same time, a stainless steel plate of 70×80×0.5 cm is used as the cathode plate, and the anode and cathode are placed in a heterogeneous cationic membrane electrolyzer. The anode liquid obtained in Example 1 is filtered, and the filtrate after the cathode liquid precipitates sodium antimonate, and 655 g of sodium hydroxide and an appropriate amount of solution are added to adjust the NaOH to 280 L of electrolyte of 140 g / L, and the electrolyte is evenly distributed in the cathode chamber and the anode chamber, and the temperature is 60 ° C, 300 A / m 2The electrochemical dissolution process of precious antimony was carried out by passing electricity at a current density of 1.50 V for 50 h. The cell voltage during the electrolysis process was about 1.52 V. After the power was turned on, the antimony concentration in the electrolyte was 89.83 g / L. At the same time, the electrolytes in the cathode chamber and the anode chamber were mixed and filtered. After filtration, 47.87 g of anode mud was obtained, of which the gold content was 3.87% and the silver content was 7.64%. The obtained anode mud was filtered, dried and sent to the precious metal workshop for treatment.

[0045] Step 2: At a temperature of 85 °C and a shear speed of 6000 r / min, 5.25 m 3 Air (0.90 times the theoretical amount) was slowly introduced into the antimony-containing solution obtained in step 1 over 6 hours. After the reaction was completed, 17.44 kg of sodium pyroantimonate was obtained by filtration and drying. 2 O 2 The utilization rate reaches 97.34%. The arsenic content of sodium pyroantimonate products is 0.001%, the lead content is 0.002%, and the iron content is 0.002%, meeting the quality requirements of first-class products in YS / T 22-2010.

[0046] Comparative Example 1 (Excessive content of impurity elements in precious antimony)

[0047] The process conditions of Comparative Example 1 are basically the same as those of Example 1, except that in step 1 of Comparative Example 1, the arsenic content of noble antimony is 1.32%, the iron content is 4.97%, and the lead content is 3.41%. After electrochemical dissolution of noble antimony, a large amount of Fe(OH) 3 After electrolysis, the anode mud only produced 3.14 kg of sodium pyroantimonate, which was lower than that of comparative example 1. The arsenic content of the product sodium pyroantimonate was 0.007%, the lead content was 0.013%, and the iron content was 0.008%, which did not meet the requirements of YS / T 22-2010.

[0048] Comparative Example 2 (Cation Exchange Membrane Not Used in the Electrochemical Dissolution Step of Precious Antimony)

[0049] The process conditions of Comparative Example 2 are basically the same as those of Example 1, except that in step 1, no cation exchange membrane is used to separate the cathode and anode chambers. After the electrodeposition is completed, 1.66 kg of antimony powder is mixed in the electrolyte, and the anode mud enriched with precious metals cannot be collected in step 1. Combined with the mass of antimony powder suspended in the electrolyte and the weight loss of precious antimony, the effective anode efficiency in step 1 is only 21.70%.

[0050] Comparative Example 3 (Preparation of Sodium Pyroantimonate by Oxidation of Sodium Antimonite without Using Shear Strengthening Technology)

[0051] The process conditions of Comparative Example 2 are basically the same as those of Example 1, except that in step 2, only paddle stirring is used in Comparative Example 2. After step 2, only 4.15 kg of sodium pyroantimonate is obtained, which is much less than that of Example 1.

[0052] Comparative Example 4 (H 2 O 2 The dosage is higher than the theoretical amount required)

[0053] The process conditions of Comparative Example 2 are basically the same as those of Example 1, except that in step 2 of Comparative Example 4, the amount of hydrogen peroxide used is 2.03 kg (1.05 times the theoretical amount). After the electrolyte is oxidized to prepare sodium pyroantimonate, the electrochemical dissolution of noble antimony in step 1 is repeated. The initial electrolysis voltage rises directly to 3.46 V, and the anode surface turns black, showing passivation, and the electrolyte circulation fails.

Claims

1. A method for recovering precious metals from precious antimony and preparing sodium pyroantimonate, characterized in that: Precious antimony is melted and cast into an anode, which is placed in an electrolytic cell. Sodium hydroxide solution is used as the electrolyte, and electrochemical oxidation and dissolution are performed to obtain a solution containing sodium antimonite and anode mud enriched with precious metals. An oxidant is added to the solution containing sodium antimonite, and sodium pyroantimonate is obtained by shear-enhanced oxidation of sodium antimonite.

2. A method for recovering precious metals from precious antimony and preparing sodium pyroantimonate according to claim 1, characterized in that: The precious antimony has an antimony content of ≥97.0%, an arsenic content of <0.5%, a lead content of <0.5%, an iron content of <0.5%, a gold content of 1-50000 g / t, and a silver content of 1-50000 g / t.

3. A method for recovering precious metals from precious antimony and preparing sodium pyroantimonate according to claim 1, characterized in that: The electrolytic cell comprises an anode chamber, a cathode chamber and a cation exchange membrane; wherein the cation exchange membrane separates the anode chamber from the cathode chamber.

4. A method for recovering precious metals from precious antimony and preparing sodium pyroantimonate according to claim 3, characterized in that: The cation exchange membrane is one of a homogeneous ion exchange membrane, a semi-homogeneous ion exchange membrane and a heterogeneous ion exchange membrane; The anode chamber accommodates an anode, the cathode chamber accommodates a cathode, and the electrolyte is distributed in the anode chamber and the cathode chamber.

5. A method for recovering precious metals from precious antimony and preparing sodium pyroantimonate according to any one of claims 1 to 3, characterized in that: The cathode used in the electrochemical oxidation dissolution is selected from one of a stainless steel plate, a graphite plate and a titanium plate.

6. A method for recovering precious metals from precious antimony and preparing sodium pyroantimonate according to any one of claims 1 to 3, characterized in that: The concentration of the sodium hydroxide solution is 40-200 g / L; The temperature during the electrochemical oxidation dissolution is 30-80 °C; the anode current density is 50-400 A / m 2 .

7. A method for recovering precious metals from precious antimony and preparing sodium pyroantimonate according to any one of claims 1 to 3, characterized in that: After the electrochemical oxidation dissolution is completed, the electrolytic cell and the anode residue are rinsed with clean water, the obtained washing water is combined with the electrolyte, and then the solid-liquid separation is performed. The obtained liquid phase is a solution containing sodium antimonite, and the obtained solid phase is anode mud enriched with precious metals. The anode mud enriched with precious metals is sent to the precious metal workshop to extract the precious metals.

8. The method for recovering precious metals from precious antimony and preparing sodium pyroantimonate according to claim 1, characterized in that: The oxidant is selected from one or more of air, oxygen, ozone, hydrogen peroxide, and sodium hypochlorite, and the amount of the oxidant is 0.8 to 1.0 times the theoretical amount of sodium pyroantimonate to oxidize sodium antimonite.

9. A method for recovering precious metals from precious antimony and preparing sodium pyroantimonate according to claim 1 or 8, characterized in that: The shear rate of the shear enhanced oxidation is 1000-10000 r / min; The shearing form of the shear-enhanced oxidation is one of internal shearing and external shearing or a combination of both; The temperature of the shear enhanced oxidation is 40-98 °C and the time is 2-6 h.

10. A method for recovering precious metals from precious antimony and preparing sodium pyroantimonate according to claim 1 or 8, characterized in that: An oxidant is added to a solution containing sodium antimonite, and sodium antimonite is oxidized by shearing to obtain a solution containing sodium pyroantimonate. The solid-liquid separation is performed, and the obtained solid phase is dried to obtain sodium pyroantimonate. The obtained liquid phase is supplemented with sodium hydroxide and then returned as an electrolyte for the electrochemical oxidation dissolution of the next batch of precious antimony. The molar amount of the supplemented sodium hydroxide is equal to the molar amount of the solid-liquid separated sodium pyroantimonate.

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