Process for preparing high-purity antimony from crude antimony white powder

Abstract

The invention relates to a process for preparing high-purity antimony by using crude antimony white powder. The method comprises the following steps of: mixing Sb2O3 with the content gt; the method comprises the following steps: washing 95% crude antimony white powder with deionized water at normal temperature, drying, dissolving with high-quality hydrochloric acid, and filtering to obtain an antimony trichloride stock solution; concentrating the antimony trichloride stock solution to obtain a concentrated solution, rectifying the concentrated solution twice, discarding high-boiling-point and low-boiling-point substances, and performing hydrogen reduction on an intermediate material subjected to secondary rectification to obtain reduced antimony; the reduced antimony is sequentially subjected to surface treatment, vacuum distillation and zone-melting purification, and a high-purity antimony product with the purity larger than 99.9999% is obtained. The method is easy to operate and has very high practicability, and the obtained high-purity antimony product is high in purity and high in application value.

Description

Technical Field

[0001] The present invention relates to a preparation technology of ultra-purified crude products by chemical metallurgical methods, and in particular to a process for preparing high-purity antimony by using crude antimony white powder. Background Art

[0002] Antimony white is an important inorganic compound. It is usually white or gray orthorhombic or equiaxed crystalline powder and is odorless. It turns yellow after thermal decomposition and turns white or gray after cooling. The main use of antimony white is as a flame retardant, especially in rubber, plastic, textile, electronics, electrical appliances and other products. It is also an important raw material for the production of enamel, pigment, paint, plastic, glass, ceramics, fireproof fabrics, etc. In addition, antimony white can also be used for biochemical research.

[0003] High-purity antimony is now widely used in the production of various flame retardants, alloys, ceramics, glass, pigments, semiconductor components, medicine and chemical industries. Among them, antimony used in the production of flame retardants accounts for about 60% of the total antimony consumption, antimony consumed in the manufacture of alloy materials, sliding bearings and welding agents in batteries accounts for about 20%, and consumption in other aspects is about 20%. The main function of antimony in alloys is to increase hardness, and it is often used as a hardener for metals or alloys. Antimony is also used in biology or medicine. High-purity antimony and antimony metal compounds (indium antimony, silver antimony, gallium antimony, etc.) are also ideal materials for the production of semiconductors and thermoelectric devices. Antimony is also used to make bullets and bullet tracers; antimony-124 and beryllium are used together as neutron sources; antimony sulfides have been shown to stabilize the friction coefficient of automotive brake pad materials.

[0004] At present, the preparation methods of high-purity antimony mainly include: electrolysis, chlorination reduction, zone smelting, and vacuum distillation. Although there are many methods, due to the limitations of production technology, it is difficult to increase the output and widely use it, and it has high technical requirements for various control links of the process. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a process for preparing high-purity antimony from crude antimony white powder which is easy to operate and has strong practicability.

[0006] In order to solve the above problems, the present invention discloses a process for preparing high-purity antimony from crude antimony white powder, characterized in that: the method comprises: 2 O 3 The crude antimony white powder with a content of more than 95% is washed with deionized water at room temperature, dried, dissolved with high-grade hydrochloric acid, and filtered to obtain an antimony trichloride stock solution; the antimony trichloride stock solution is concentrated to obtain a concentrated solution, the concentrated solution is distilled twice, high-boiling point and low-boiling point substances are discarded, and the intermediate material of the secondary distillation is reduced with hydrogen to obtain reduced antimony; the reduced antimony is sequentially subjected to surface treatment, vacuum distillation, and zone melting purification to obtain a high-purity antimony product with a purity of more than 99.9999%.

[0007] The ratio of the crude antimony white powder to the premium hydrochloric acid is 1 kg:2.5 L.

[0008] The concentration ratio is 5:2.

[0009] The two distillations are carried out as follows: ⑴ Primary distillation: The concentrated liquid is added into the distillation tower A, hydrochloric acid and water are constant boiling substances, the temperature is 108°C, the reflux volume ratio is 10:1, and the outflow rate is 150-200ml / h; the total reflux temperature is 210-230°C, and the reflux time is 2 h; the temperature of the low-boiling-point substance A is 210-230°C, the reflux volume ratio is 10:1, the fraction volume ratio is 5%, the flow rate is 100ml / h, and 100ml of 1:1 high-grade hydrochloric acid is added to the receiving bottle; the temperature of the intermediate material A is 220-250°C, the reflux volume ratio is 10:1, the fraction volume ratio is 70%, the outflow rate is 100-150ml / h, and 100ml of 1:1 high-grade hydrochloric acid is added to the special receiving bottle; the temperature of the high-boiling-point substance A is >250°C, and the fraction volume ratio is 25%; the low-boiling-point substance A and the high-boiling-point substance A are discarded; ⑵Secondary distillation: The intermediate material A is added into the distillation tower B, the hydrochloric acid and water are constant boiling substances, the temperature is 108°C, the reflux volume ratio is 10:1, and the outflow rate is 150-200ml / h; the total reflux is 210-230°C, and the time is 2 h; the temperature of the low-boiling-point substance B is 210-230°C, the reflux volume ratio is 30:1, the fraction volume ratio is 5%, the outflow rate is 100-150ml / h, and 100ml of 1:1 superior hydrochloric acid is added into the receiving bottle; the temperature of the intermediate material B is 220-250°C, the reflux volume ratio is 30:1, the fraction volume ratio is 85%, the outflow rate is 100-150ml / h, and the special receiving bottle is clean and dry; the temperature of the high-boiling-point substance B is >250°C, and the fraction volume ratio is 10%; the low-boiling-point substance B and the high-boiling-point substance B are discarded, and the intermediate material B is the intermediate material of the secondary distillation.

[0010] The hydrogen reduction refers to loading the intermediate material of the secondary distillation into the evaporation boat in turn, sealing the furnace cover, opening nitrogen for 3-5 minutes to drive away the air in the reduction furnace, and then passing hydrogen for 30 minutes, with a hydrogen flow rate of 500ml / min, and opening the copper scrap furnace, reduction furnace, evaporation furnace, and exhaust polytetrafluoroethylene pipeline heating system, the copper scrap furnace temperature is 500°C, the reduction furnace temperature is 850-900°C, and the evaporation furnace temperature is 140-150°C, and the addition reduction begins; in the first 2 hours, the addition amount is controlled at 10ml / h, and added in four times, and after 2 hours, it is slowly added without overflowing, and after the addition is completed, it is kept warm at 850-900°C for 1 hour; after the reduction is completed, the temperature is lowered, and when the furnace temperature drops to 200°C, the nitrogen valve is opened to pass nitrogen and the hydrogen valve is closed. When the furnace temperature drops below 80°C, the nitrogen valve is closed and the nitrogen is stopped; the reduction furnace is opened, and the product antimony reduction is taken out in a clean environment.

[0011] The surface treatment refers to soaking the reduced antimony in 1:1 high-grade hydrochloric acid for 1 to 1.5 hours, then washing with deionized water until neutral, and drying at 60° C. to constant weight to obtain an antimony ingot.

[0012] The vacuum distillation is to load the surface treated antimony ingot into the distillation boat, and then load it into the horizontal distillation furnace after all the inspections are completed. The boat is straightened and vacuumized <8×10 -3 m / m mercury column and then heated; when the distillation temperature is 680~700℃, the vacuum degree is <10×10 -3 m / m mercury column to start evaporation and distillation operations, control the condensation temperature at 500~550℃, the evaporation temperature at 550℃, start cooling after evaporation for 1h, and turn off the heating system and condensation system; when the temperature is about to be below 80℃, turn off the vacuum pump and prepare for discharging; among them: the coarse crystalline antimony particles with good metallic luster in 1~5 sections of the material boat are taken out as the finished product, and the materials in 6~7 sections of the material boat and the materials with poor metallic luster are processed collectively.

[0013] The zone melting purification refers to loading the finished antimony particles after vacuum distillation into a zone melting boat and loading it into a tubular zone melting furnace, the boat length is 400-500 mm, the zone melting width is 3-5 mm, each boat is loaded with 1000 grams, the annular heater is used for heating, the furnace tube is evacuated and hydrogen is introduced to 15 MPa, zone melting is carried out in a hydrogen atmosphere, after the ingot is melted flat, the tail end of the furnace tube is raised to make the zone melting boat tilted by 1%, the zone melting speed is 60 mm / h, the zone melting is performed 18-20 times, and the zone melting is stopped when the surface quality is flat and mirror-like, there is no material accumulation and no scum, the heating system is turned off, the temperature in the tube drops to below 80°C to prepare for discharging, exhaust, and open the furnace tube; the zone melting boat is taken out, and the material at the head 30 mm and the tail 30-50 mm of the boat is returned for re-steaming, and the middle part is the high-purity antimony product with a purity of more than 99.9999%.

[0014] Compared with the prior art, the present invention has the following advantages: 1. The present invention has experimentally determined a process for preparing high-purity antimony from crude antimony white powder. The process is easy to operate and has strong practicality. Impurities are removed in stages during the whole process, and the purity of the obtained antimony is higher. The reason is that the impurity removal components and degrees are different in each stage.

[0015] 2. The purification method of the present invention combines rectification, vacuum distillation and zone melting to obtain antimony with higher purity, and the obtained product achieves the purpose of high-purity or ultra-pure product. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0017] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0018] like Figure 1 As shown in the figure, a process for preparing high-purity antimony from crude antimony white powder is described. 2 O 3 The crude antimony white powder with a content of >95% is washed with deionized water at room temperature to remove soluble impurity ions. The washed antimony white is dried, dissolved with high-grade hydrochloric acid, and filtered to obtain antimony trichloride stock solution; the antimony trichloride stock solution is concentrated to obtain a concentrated solution, which is distilled twice, and high-boiling and low-boiling point substances are discarded. The intermediate material of the secondary distillation is reduced with hydrogen to obtain reduced antimony; the reduced antimony is sequentially subjected to surface treatment, vacuum distillation, and zone melting purification to obtain a high-purity antimony product with a purity of >99.9999%. The specific process is as follows: S1 will Sb 2 O 3 The crude antimony white powder with a content of >95% is washed with deionized water at room temperature to remove soluble impurity ions. The washed antimony white is dried and dissolved in high-grade hydrochloric acid. The ratio of crude antimony white powder to high-grade hydrochloric acid is 1kg:2.5L. After dissolution, it is filtered to obtain antimony trichloride stock solution.

[0019] The S2 antimony trichloride stock solution is concentrated at a concentration ratio of 5:2 to obtain a concentrated solution. During the concentration, pay attention to controlling the temperature to prevent overflow.

[0020] The S3 concentrate is distilled twice: ⑴ Primary distillation: Add the concentrated liquid into the distillation tower A, hydrochloric acid and water are constant boiling substances, the temperature is 108℃, the reflux volume ratio is 10:1, and the outflow rate is 150~200ml / h; the total reflux temperature is 210~230℃, and the reflux time is 2 h; the temperature of low-boiling point substance A is 210~230℃, the reflux volume ratio is 10:1, the fraction volume ratio is 5%, the flow rate is 100ml / h, and 100ml of 1:1 high-grade hydrochloric acid is added to the receiving bottle; the temperature of intermediate material A is 220~250℃, the reflux volume ratio is 10:1, the fraction volume ratio is 70%, the outflow rate is 100~150ml / h, and 100ml of 1:1 high-grade hydrochloric acid is added to the special receiving bottle; the temperature of high-boiling point substance A is >250℃, and the fraction volume ratio is 25%; the low-boiling point substance A and the high-boiling point substance A are discarded.

[0021] ⑵Secondary distillation: Add intermediate material A into distillation tower B, hydrochloric acid and water are constant boiling substances, temperature is 108℃, reflux volume ratio is 10:1, and outflow rate is 150~200ml / h; total reflux is 210~230℃, time is 2 h; low boiling point substance B temperature is 210~230℃, reflux volume ratio is 30:1, fraction volume ratio is 5%, outflow rate is 100~150ml / h, 100ml of 1:1 superior hydrochloric acid is added to the receiving bottle; intermediate material B temperature is 220~250℃, reflux volume ratio is 30:1, fraction volume ratio is 85%, outflow rate is 100~150ml / h, and the special receiving bottle is clean and dry; high boiling point substance B temperature is >250℃, fraction volume ratio is 10%; low boiling point substance B and high boiling point substance B are discarded, and intermediate material B is the intermediate material for secondary distillation.

[0022] The intermediate materials of S4 secondary distillation are loaded into the evaporation boat in turn, the furnace cover is sealed, the nitrogen is opened for 3~5 minutes to drive away the air in the reduction furnace, and then the hydrogen is passed for 30 minutes, the hydrogen flow rate is 500ml / min, and the copper scrap furnace, reduction furnace, evaporation furnace, exhaust PTFE pipeline heating system are turned on, the copper scrap furnace temperature is 500℃, the reduction furnace temperature is 850~900℃, and the evaporation furnace temperature is 140~150℃, and the addition reduction is started; the feeding amount is controlled at 10ml / h in the first 2 hours, and it is added in four times to form crystal nuclei and improve the reduction rate. After 2 hours, it is slowly added without overflowing. After adding the materials, keep warm at 850~900℃ for 1 hour; after the reduction is completed, the temperature is turned on. When the furnace temperature drops to 200℃, the nitrogen valve is opened to pass nitrogen and the hydrogen valve is closed. When the furnace temperature drops below 80℃, the nitrogen valve is closed and the nitrogen is stopped; the reduction furnace is turned on, and the product antimony reduction is taken out in a clean environment.

[0023] Since there is unreduced antimony trichloride and its white aqueous medium on the surface of reduced antimony S5, the reduced antimony is soaked in 1:1 high-grade hydrochloric acid for 1-1.5 h, then washed with deionized water until neutral, and dried at 60°C to constant weight to obtain an antimony ingot.

[0024] S6: Load the surface treated antimony ingot into the distillation boat, and after all the inspections are completed, load it into the horizontal distillation furnace in sequence. Straighten the boat and evacuate the vacuum to <8×10 -3 m / m mercury column and then increase the temperature, adjust the temperature control point to prevent thermal inertia. When the distillation temperature is 680~700℃, the vacuum degree is <10×10 -3 m / m mercury column to start evaporation and distillation operation, control the condensation temperature at 500~550℃, the evaporation temperature at 550℃, start cooling after evaporation for 1h, and turn off the heating system and condensation system; when the temperature is about to be below 80℃, turn off the vacuum pump and prepare for discharging; among them: the coarse crystalline antimony particles with good metallic luster in the 1st to 5th material boats are taken out as finished products, and the 6th to 7th boats and materials with poor metallic luster are centrally processed. The bad parts are returned for re-evaporation.

[0025] Carbon can be removed by vacuum distillation, and iron, copper, calcium, oxides and antimony trichloride attachments can also be removed. The finished product can be free of dust pollution and the content of calcium, magnesium and aluminum can be increased. In addition to the above, crude antimony can also be removed by vacuum distillation. Selenium, tellurium, lead, tin, sulfur and other impurities, but the effect of removing arsenic is not good, and lead removal is not thorough.

[0026] S7: The finished antimony particles after vacuum distillation are loaded into a zone melting boat and then loaded into a tubular zone melting furnace. The boat length is 400-500mm, the zone melting width is 3-5mm, and each boat is loaded with 1000g. The annular heater is used for heating. After the furnace tube is evacuated, hydrogen is introduced to 15MPa. Zone melting is carried out in a hydrogen atmosphere. After the ingot is melted flat, the tail end of the furnace tube is raised to make the zone melting boat tilted by 1%. The zone melting speed is 60mm / h, and the zone melting is performed 18-20 times. When the surface quality is flat and mirror-like, there is no material accumulation and no slag, the zone melting is stopped, the heating system is turned off, the temperature in the tube drops below 80℃ to prepare for discharging, exhaust, and open the furnace tube; the zone melting boat is taken out in a clean environment, and the material at the head 30mm and the tail 30-50mm of the boat is returned for re-steaming, and the middle part is the high-purity antimony product with a purity of more than 99.9999%.

[0027] The products are collected under clean environmental conditions to ensure that the high-purity antimony produced is not contaminated.

[0028] The zone melting process mainly controls impurities: lead, tin, copper, selenium, tellurium, silicon, and calcium. Thermoelectric materials, semiconductor compound raw materials or according to user requirements can be used for doping silicon single crystals.

[0029] Example 1 A process for preparing high-purity antimony from crude antimony white powder comprises the following steps: S1 will 1kg Sb 2 O 3 The crude antimony white powder with a content of >95% is washed with deionized water at room temperature to remove soluble impurity ions. The washed antimony white is dried, dissolved in 2.5L of high-grade hydrochloric acid, and filtered to obtain antimony trichloride stock solution.

[0030] The S2 antimony trichloride stock solution is concentrated at a concentration ratio of 5:2 to obtain a concentrated solution.

[0031] The S3 concentrate was distilled twice: the process conditions of the distillation are shown in Table 1.

[0032] Table 1 Process conditions for double distillation The fractions should be measured correctly, the material should be discharged evenly, the material should be prevented from rushing, the cooling water should be controlled to prevent freezing, the bottles for the intermediate materials should be clean, the distillation chamber should be kept clean, and dust and asbestos mud should be prevented from mixing into the intermediate materials. Stop the tower and cool down to below 180℃, add 100-200ml hydrochloric acid to cool and extract the high boiling point.

[0033] 5000g of the intermediate material of S4 secondary distillation was loaded into the evaporation boat in turn, the furnace cover was sealed, nitrogen was turned on for 3~5 minutes to drive away the air in the reduction furnace, and then hydrogen was turned on for 30 minutes, with a hydrogen flow rate of 500ml / min, and the copper scrap furnace, reduction furnace, evaporation furnace, and exhaust PTFE pipeline heating system were turned on. The temperature of the copper scrap furnace was 500℃, the temperature of the reduction furnace was 850~900℃, and the temperature of the evaporation furnace was 140~150℃, and the addition reduction began; the addition amount was controlled at 10ml / h in the first 2 hours, and it was added in four times to form crystal nuclei and improve the reduction rate. After 2 hours, it was added slowly without overflowing, and after adding the materials, it was kept warm at 850~900℃ for 1 hour; after the reduction was completed, the temperature was turned on, and when the furnace temperature dropped to 200℃, the nitrogen valve was opened to pass nitrogen and the hydrogen valve was closed. When the furnace temperature dropped below 80℃, the nitrogen valve was closed and the nitrogen was stopped; the reduction furnace was turned on, and the product antimony reduction was taken out in a clean environment. The reduction rate was 95%.

[0034] S5: Soak the reduced antimony in 1:1 high-grade hydrochloric acid for 1-1.5 h, then wash with deionized water until neutral, and dry at 60°C to constant weight to obtain an antimony ingot.

[0035] S6: Load the surface treated antimony ingots into the distillation boat, with a batch size of 600g / tube, two tubes in total. After all inspections are completed, load them into the horizontal distillation furnace in sequence, straighten the boat, and evacuate to a vacuum of <8×10 -3 m / m mercury column and then increase the temperature. When the distillation temperature is 680~700℃, the vacuum degree is <10×10 -3 m / m mercury column to start evaporation and distillation operation, control the condensation temperature at 500~550℃, the evaporation temperature at 550℃, start cooling after evaporation for 1h, and turn off the heating system and condensation system; when the temperature is about to be below 80℃, turn off the vacuum pump and prepare for discharging; among them: the coarse crystalline antimony particles with good metallic luster in the 1st to 5th section material boat are taken out as finished products, and the 6th to 7th section boat and the materials with poor metallic luster are processed collectively. The poor part is returned for re-distillation, and the finished product after distillation is 75~85%.

[0036] S7: Load the finished antimony particles after vacuum distillation into the zone melting boat, push the zone melting boat into the tubular zone melting furnace, the boat length is 400~500mm, the zone melting width is 3~5mm, each boat is loaded with 1000g, the ring heater is heated, the furnace tube is evacuated and hydrogen is introduced to 15MPa, and the zone melting is carried out in a hydrogen atmosphere. After the ingot is melted flat, the tail end of the furnace tube is raised to make the zone melting boat tilted by 1%, the zone melting speed is 60 mm / h, and the zone melting is repeated 18~20 times. When the surface quality is flat and mirror-like, there is no material accumulation and no slag, the zone melting is stopped, the heating system is turned off, the temperature in the tube drops below 80℃, and the material is ready for discharge, exhaust, and the furnace tube is opened; the zone melting boat is taken out in a clean environment, and the material at the head 30mm and the tail 30~50mm of the boat is returned for re-steaming, and the middle part is the high-purity antimony product with a purity of >99.9999%. The product yield is >85%.

Claims

1. A process for preparing high-purity antimony from crude antimony white powder, characterized in that: The method comprises washing crude antimony white powder with a Sb2O3 content of more than 95% with deionized water at room temperature, drying, dissolving with high-grade hydrochloric acid, and filtering to obtain an antimony trichloride stock solution; concentrating the antimony trichloride stock solution to obtain a concentrated solution, subjecting the concentrated solution to two distillations, discarding high-boiling point and low-boiling point substances, and subjecting the intermediate material of the two distillations to hydrogen reduction to obtain reduced antimony; The reduced antimony is sequentially subjected to surface treatment, vacuum distillation, and zone melting purification to obtain a high-purity antimony product with a purity greater than 99.9999%.

2. A process for preparing high-purity antimony from crude antimony white powder as claimed in claim 1, characterized in that: The ratio of the crude antimony white powder to the premium hydrochloric acid is 1 kg:2.5 L.

3. A process for preparing high-purity antimony from crude antimony white powder as claimed in claim 1, characterized in that: The concentration ratio is 5:

2.

4. A process for preparing high-purity antimony from crude antimony white powder as claimed in claim 1, characterized in that: The two distillations are carried out as follows: ⑴ Primary distillation: The concentrated liquid is added into the distillation tower A, hydrochloric acid and water are constant boiling substances, the temperature is 108°C, the reflux volume ratio is 10:1, and the outflow rate is 150-200ml / h; the total reflux temperature is 210-230°C, and the reflux time is 2 h; the temperature of the low-boiling-point substance A is 210-230°C, the reflux volume ratio is 10:1, the fraction volume ratio is 5%, the flow rate is 100ml / h, and 100ml of 1:1 high-grade hydrochloric acid is added to the receiving bottle; the temperature of the intermediate material A is 220-250°C, the reflux volume ratio is 10:1, the fraction volume ratio is 70%, the outflow rate is 100-150ml / h, and 100ml of 1:1 high-grade hydrochloric acid is added to the special receiving bottle; the temperature of the high-boiling-point substance A is >250°C, and the fraction volume ratio is 25%; the low-boiling-point substance A and the high-boiling-point substance A are discarded; ⑵Secondary distillation: The intermediate material A is added into the distillation tower B, the hydrochloric acid and water are constant boiling substances, the temperature is 108°C, the reflux volume ratio is 10:1, and the outflow rate is 150-200ml / h; the total reflux is 210-230°C, and the time is 2 h; the temperature of the low-boiling-point substance B is 210-230°C, the reflux volume ratio is 30:1, the fraction volume ratio is 5%, the outflow rate is 100-150ml / h, and 100ml of 1:1 superior hydrochloric acid is added into the receiving bottle; the temperature of the intermediate material B is 220-250°C, the reflux volume ratio is 30:1, the fraction volume ratio is 85%, the outflow rate is 100-150ml / h, and the special receiving bottle is clean and dry; the temperature of the high-boiling-point substance B is >250°C, and the fraction volume ratio is 10%; the low-boiling-point substance B and the high-boiling-point substance B are discarded, and the intermediate material B is the intermediate material of the secondary distillation.

5. The process for preparing high-purity antimony from crude antimony white powder as claimed in claim 1, characterized in that: The hydrogen reduction refers to loading the intermediate material of the secondary distillation into the evaporation boat in sequence, sealing the furnace cover, opening nitrogen for 3-5 minutes to drive away the air in the reduction furnace, and then passing hydrogen for 30 minutes, with a hydrogen flow rate of 500ml / min, and opening the copper scrap furnace, reduction furnace, evaporation furnace, and exhaust PTFE pipeline heating system, with the temperature of the copper scrap furnace at 500°C, the temperature of the reduction furnace at 850-900°C, and the temperature of the evaporation furnace at 140-150°C, and starting the feeding reduction; in the first 2 hours, the feeding amount is controlled at 10ml / h, and added in four times, and then slowly added without overflow after 2 hours, and kept warm at 850-900°C for 1 hour after the addition of the materials; After the reduction is completed, start cooling. When the furnace temperature drops to 200℃, open the nitrogen valve to pass nitrogen and close the hydrogen valve. When the furnace temperature drops below 80℃, close the nitrogen valve and stop passing nitrogen; start the reduction furnace and take out the product antimony reduction in a clean environment.

6. The process for preparing high-purity antimony from crude antimony white powder as claimed in claim 1, characterized in that: The surface treatment refers to soaking the reduced antimony in 1:1 high-grade hydrochloric acid for 1 to 1.5 hours, then washing with deionized water until neutral, and drying at 60° C. to constant weight to obtain an antimony ingot.

7. A process for preparing high-purity antimony from crude antimony white powder as claimed in claim 1, characterized in that: The vacuum distillation is to load the surface treated antimony ingot into the distillation boat, and then load it into the horizontal distillation furnace after all the inspections are completed. The boat is straightened and vacuumized <8×10 -3 m / m mercury column and then heated; when the distillation temperature is 680~700℃, the vacuum degree is <10×10 -3 m / m mercury column to start evaporation and distillation operations, control the condensation temperature at 500~550℃, the evaporation temperature at 550℃, start cooling after evaporation for 1h, and turn off the heating system and condensation system; when the temperature is about to be below 80℃, turn off the vacuum pump and prepare for discharging; among them: the coarse crystalline antimony particles with good metallic luster in 1~5 sections of the material boat are taken out as the finished product, and the materials in 6~7 sections of the material boat and the materials with poor metallic luster are processed collectively.

8. The process for preparing high-purity antimony from crude antimony white powder as claimed in claim 1, characterized in that: The zone melting purification refers to loading the finished antimony particles after vacuum distillation into a zone melting boat and loading it into a tubular zone melting furnace, the boat length is 400-500 mm, the zone melting width is 3-5 mm, each boat is loaded with 1000 grams, the annular heater is used for heating, the furnace tube is evacuated and hydrogen is introduced to 15 MPa, zone melting is carried out in a hydrogen atmosphere, after the ingot is melted flat, the tail end of the furnace tube is raised to make the zone melting boat tilted by 1%, the zone melting speed is 60 mm / h, the zone melting is performed 18-20 times, and the zone melting is stopped when the surface quality is flat and mirror-like, there is no material accumulation and no scum, the heating system is turned off, the temperature in the tube drops to below 80°C to prepare for discharging, exhaust, and open the furnace tube; the zone melting boat is taken out, and the material at the head 30 mm and the tail 30-50 mm of the boat is returned for re-steaming, and the middle part is the high-purity antimony product with a purity of more than 99.9999%.

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