CN116692941A - A method for preparing high-quality sodium pyroantimonate by step purification and oxidation - Google Patents

Abstract

A process for preparing high-quality sodium pyroantimonate by gradient purification and oxidization includes such steps as leaching the antimonic sulfide minerals in sodium sulfide solution, adding the antimonic sulfide minerals to the leached liquid for preliminary iron removal, adding activated carbon to the liquid after preliminary iron removal, deep iron removal, oxidizing by oxygen at low temp, removing impurities, and oxidizing by oxygen at high temp. The essence of the invention is that the purpose of preparing high-quality sodium pyroantimonate is realized by adopting a combination mode of echelon purification and echelon oxidation. The sodium thiosulfate solution is prepared by adding the preliminary purification of the antimony sulfide-containing mineral and the deep purification of the activated carbon adsorption, and the high-quality sodium pyroantimonate product is prepared by low-temperature pressurized oxidation and high-temperature pressurized oxidation. The invention has the advantages of good product quality, environmental protection and simple operation.

Description

A method for preparing high-quality sodium pyroantimonate by step purification and oxidation

technical field

The invention relates to a hydrometallurgical process in the field of metallurgy, in particular to a hydrometallurgical method for preparing high-quality sodium pyroantimonate from mineral raw materials containing antimony sulfide.

Background technique

Antimony is a silver-white non-ferrous metal that is brittle, poor in electrical conductivity and thermal conductivity, and is mainly used in alloys, flame retardants, military industry and glass industries. Antimony production in the world is mainly concentrated in China, Tajikistan, Russia, Australia, Bolivia and other countries, and my country is the largest antimony producing country in the world. Mineral raw materials for antimony metallurgy mainly include stibnite, antimony gold ore and brittle stibnite, and antimony in these raw materials exists in the form of stibnite. The antimony-containing soot produced in the heavy metal lead smelting process is an important antimony secondary material, in which antimony mainly exists in the form of oxides.

The antimony metallurgical process mainly includes pyrotechnics and wet-processes, in which the pyrotechnical process is to first oxidize antimony raw materials at high temperature to produce antimony oxide, then reduce antimony oxide to produce metal antimony ingots through reduction smelting and refining, and finally use antimony ingots to prepare various antimony ingots. antimony products. The wet process is to dissolve antimony into the solution in a sodium sulfide system or a chloride system, and then produce antimony products by oxidation or electrowinning. The industrial products of antimony mainly include antimony ingot, antimony white and sodium pyroantimonate.

Sodium pyroantimonate, with the molecular formula NaSb(OH) ₆ , is a white powder that is insoluble in water, dilute alkali, dilute inorganic acid and acetic acid, and soluble in tartaric acid and hot concentrated sulfuric acid. Sodium pyroantimonate is widely used in high-grade glass clarifier, chemical electronics industry, textile flame retardant, opalescent agent, paint additive and decolorizer and other fields. Due to the rapid development of the photovoltaic industry, sodium pyroantimonate is mainly used as a clarifying agent in the production process of photovoltaic glass. The preparation methods of sodium pyroantimonate include fire process and wet process. These methods are to oxidize Sb(Ⅲ) to Sb(Ⅴ) with oxidants such as sodium nitrate, hydrogen peroxide, air or oxygen under specific conditions to obtain pyroantimonate. sodium products.

Sodium nitrate oxidation is a typical representative of pyrotechnics. Sodium nitrate oxidation is a pyrotechnic process for preparing sodium antimonate by oxidizing metal antimony or antimony trioxide with sodium nitrate under high temperature and alkaline conditions. Although the fire process has the advantages of simple operation and low production cost, because sodium nitrate is used as an oxidant in the high-temperature production process, harmful gases are generated during the reaction process, and there are disadvantages of poor product quality and serious environmental pollution. At present, this method has been eliminated.

The wet process is divided into acidic system and alkaline system. The acidic system is represented by the chlorination hydrolysis method. The chlorination hydrolysis method is that the material containing antimony is oxidized and leached with chlorine gas in the hydrochloric acid solution, and then sodium hydroxide is added to the leaching solution. Antimony pentachloride is hydrolyzed to produce sodium pyroantimonate product. Although the chlorination hydrolysis method has the advantages of strong raw material adaptability and good product quality, it has the disadvantages of long process, serious equipment corrosion, poor operating conditions and large waste water output.

Alkaline system includes alkaline oxidation method, potassium salt method and sodium sulfide system oxidation method. Alkaline oxidation method is also called sodium salt method or oxidation reflux method, that is, antimony white is oxidized with hydrogen peroxide in sodium hydroxide solution to generate sodium pyroantimonate product. The method has the advantages of short process flow and simple operation, but has the disadvantages of poor product quality consistency, solution volume expansion and high production cost. The potassium salt method is to oxidize and dissolve antimony white with hydrogen peroxide in potassium hydroxide solution, add sodium hydroxide to potassium pyroantimonate solution for double decomposition reaction to prepare sodium pyroantimonate, and at the same time regenerate potassium hydroxide and return it to use. This method has the advantage of good product quality, but has the problems of high production cost and solution volume expansion.

The sodium sulfide system oxidation method is mainly used to treat antimony sulfide-containing mineral raw materials that exist in the antimony mineral phase. First, stibnite, antimony gold ore or brittle lead antimonite is leached in a mixed solution of sodium sulfide and sodium hydroxide, so that antimony sulfide is dissolved together to form a sodium thioantimonite solution; secondly, a sodium thioantimonite solution Pass hydrogen peroxide, air or oxygen at high temperature for oxidation, and the precipitated product is washed and dried to obtain sodium pyroantimonate product; finally, the oxidized liquid is neutralized, concentrated and crystallized to produce sodium thiosulfate as a by-product. The sodium sulfide system oxidation method directly prepares sodium pyroantimonate products from mineral raw materials, which is especially suitable for processing complex antimony-containing materials, and the selective separation effect is very good.

Due to the use of mineral raw materials in the sodium sulfide system oxidation method, the quality of sodium pyroantimonate is difficult to meet high-quality requirements. This is because when minerals containing antimony sulfide are leached with sodium sulfide, a small amount of impurity metals such as iron and arsenic will dissolve into the leach solution, and when the leach solution is oxidized by air or pressurized to precipitate sodium pyroantimonate, iron will precipitate into pyroantimonate Sodium makes the original white sodium pyroantimonate product appear brick red, seriously affecting product quality. It has been pointed out in the literature that the leaching solution of sodium thioantimonite can be left to stand, and most of the iron will be precipitated in the form of ferrous sulfide. However, on the one hand, standing for a long time is not conducive to the continuity of industrial production. Iron precipitation is not complete during the process, which will adversely affect the subsequent oxidation process. Based on this, a method for preparing high-quality sodium pyroantimonate products from antimony sulfide-containing minerals is proposed.

Contents of the invention

In order to overcome the shortcomings of the traditional method of preparing sodium pyroantimonate from antimony sulfide-containing minerals in sodium sulfide system, a method for preparing sodium pyroantimonate by combining step purification and step oxidation is proposed, with high impurity removal rate and good product quality and hydrometallurgical methods with low processing costs.

In order to achieve the above object, the technical scheme adopted by the present invention is as follows: firstly, the minerals containing antimony sulfide are leached in sodium sulfide solution, so that most of the antimony enters the leachate in the form of sodium thioantimonite, and the leachate is obtained after liquid-solid separation. Secondly, add antimony sulfide minerals to the leaching solution for preliminary iron removal, so that most of the dissolved iron is precipitated, and the liquid and solid are separated to obtain a preliminary iron-removed liquid. Add activated carbon to the liquid after preliminary iron removal again for deep iron removal, so that the residual iron in the solution is removed by adsorption, and the liquid after liquid and solid separation is obtained after deep iron removal. Thirdly, the liquid after deep iron removal is passed through oxygen at low temperature to oxidize and remove impurities. The essence of the present invention is to realize the purpose of preparing high-quality sodium pyroantimonate by combining step purification and step oxidation. A pure sodium thioantimonite solution was prepared by adding antimony sulfide-containing minerals for preliminary purification and deep purification by adding activated carbon adsorption, and high-quality sodium pyroantimonite products were prepared by low-temperature pressurized oxidation and high-temperature pressurized oxidation. These processes Closely related, a single process cannot achieve the expected effect of preparing high-quality sodium pyroantimonate from antimony sulfide-containing minerals.

The specific process and process parameters are as follows:

1 sodium sulfide leaching

Minerals containing antimony sulfide leach antimony in sodium sulfide solution. Prepare sodium hydroxide solution with a concentration of 10-20g/L, add antimony sulfide minerals according to the ratio of liquid volume L to solid weight kg 1.0-3.0:1, and then add antimony sulfide to sodium sulfide molar ratio 2.7-3.3:1 For sodium sulfide, control the reaction temperature at 25°C and stir for 10-25 minutes. Vacuum filtration is used to separate liquid from solid. The leaching solution is sent to the subsequent preliminary iron removal process, and the leaching residue is used to extract other valuable metals.

2 Preliminary iron removal

Add antimony sulfide minerals to the leaching solution for preliminary iron removal. Add sodium sulfide to the leaching solution, use antimony sulfide minerals with an ore content of 1-20% in the leaching process, control the reaction temperature at 25°C and stir for 30-120 minutes, use vacuum filtration to separate liquid and solid, and send the liquid to deep iron removal after preliminary iron removal process, the initial iron removal slag returns to leaching.

3 deep iron removal

Add activated carbon to the liquid after preliminary iron removal for deep iron removal. Add activated carbon to the liquid after preliminary iron removal, add 10-30g of activated carbon per liter of liquid after preliminary iron removal, control the reaction temperature at 25°C and stir for 30-120min, use vacuum filtration to separate liquid and solid, and send the liquid after deep iron removal Low temperature pressure oxidation, deep iron slag washing and recycling.

4 Low temperature pressurized oxidation

After deep iron removal, the liquid is fed with oxygen at low temperature to oxidize and precipitate iron under pressure. After deep iron removal, the liquid is added to the high-pressure reactor, and oxygen is introduced to control the pressure of 0.1-0.5MPa, and the temperature is controlled to 20-30°C to stir and react for 30-120min. Pressure oxidation process, low temperature oxidation slag sent fire method to smelt antimony to recover antimony.

5 high temperature and pressure oxidation

After low-temperature oxidation, the liquid is fed with oxygen at high temperature to oxidize and precipitate sodium pyroantimonate. The liquid after low-temperature oxidation is added to the high-pressure reactor, and oxygen is introduced to control the pressure at 1.0-2.0 MPa, and the temperature is controlled at 100-120°C to stir and react for 120-420 minutes. The liquid-solid separation is carried out by vacuum filtration, and the high-temperature oxidation residue is washed and dried. Qualified sodium pyroantimonate product.

The invention is suitable for treating antimony sulfide-containing minerals, wherein the range of main components is (%) by weight percentage: Sb1.0-60.0 and S5.0-28.0.

Described sodium sulfide, sodium hydroxide are analytical pure reagents.

Compared with the method for preparing sodium pyroantimonate from traditional antimony sulfide-containing minerals in a sodium sulfide system, the present invention has the following advantages: 1. After the antimony sulfide-containing minerals of the present invention are leached in a sodium sulfide system, step purification and step oxidation are adopted successively to combine The method realizes the preparation of high-quality sodium pyroantimonate products; 2. The leaching solution adopts stepwise purification to remove iron, and the iron content in the liquid is reduced to below 0.10g/L after preliminary iron removal with antimony sulfide minerals. The iron content in the liquid is reduced to less than 0.01g/L; 3. After the deep iron removal, the liquid is treated by step oxidation. After low temperature oxidation, the iron content in the liquid is less than 0.001g/L. After low temperature oxidation, the liquid is oxidized by high temperature and pressure to prepare high-quality coke Sodium antimonate product, the antimony content in the product is greater than 48.5%, and the content of iron, lead and arsenic is all less than 0.001%; 4. The present invention has the advantages of simple process, stable technical index, low labor intensity and low production cost.

Description of drawings

Figure 1: Schematic diagram of the process flow of the present invention.

Detailed ways:

Example 1:

The main components of antimony sulfide minerals are (%): Sb8.20 and S16.35 in mass percentage. Sodium hydroxide and sodium sulfide nonahydrate are analytical reagents, the mass percentage of sodium hydroxide is not less than 96%, and the mass percentage of sodium sulfide nonahydrate is not less than 98%. Prepare a sodium hydroxide solution with a concentration of 10g/L, add antimony sulfide minerals according to the ratio of liquid volume L to solid weight kg 2.0:1, then add sodium sulfide according to the molar ratio of antimony sulfide and sodium sulfide 3.0:1, and control the temperature at 25 Stir and react at ℃ for 15 minutes, and separate the liquid and solid by vacuum filtration. The iron content in the leachate is 0.21g/L.

Add sodium sulfide to the leaching solution, use 8% antimony sulfide-containing minerals in the leaching process, control the temperature at 25°C and stir for 60 minutes, and use vacuum filtration to separate the liquid from the solid. After preliminary purification, the iron content in the solution is 0.09g/L. Add activated carbon to the liquid after preliminary iron removal, add 20g of activated carbon per liter of liquid after preliminary iron removal, control the temperature at 25°C and stir for 60 minutes, use vacuum filtration to separate liquid and solid, and the iron content in the liquid after deep purification is 0.008g/L .

After deep iron removal, the liquid is added to the high-pressure reactor, and oxygen is introduced to control the pressure of 0.3MPa. The temperature is controlled at 25°C and the reaction is stirred for 60 minutes. The liquid and solid are separated by vacuum filtration. After low-temperature oxidation, the iron content in the liquid is less than 0.001g/L. After low-temperature oxidation, the liquid is added to the high-pressure reactor, and oxygen is introduced to control the pressure at 1.8MPa, and the temperature is controlled at 110°C to stir and react for 240 minutes. Vacuum suction filtration is used to separate the liquid from the solid. After washing and drying, the precipitated product is a qualified sodium pyroantimonate product. The antimony content is 48.75%, and the iron and arsenic content are both less than 0.001%.

Example 2:

The main components of antimony sulfide minerals are (%): Sb12.30 and S18.64 in mass percent. Sodium hydroxide and sodium sulfide nonahydrate are analytical reagents, the mass percentage of sodium hydroxide is not less than 96%, and the mass percentage of sodium sulfide nonahydrate is not less than 98%. Prepare a sodium hydroxide solution with a concentration of 10g/L, add antimony sulfide minerals according to the ratio of liquid volume L to solid weight kg 2.0:1, then add sodium sulfide according to the molar ratio of antimony sulfide and sodium sulfide 3.0:1, and control the temperature at 25 Stir and react at ℃ for 15 minutes, and separate the liquid and solid by vacuum filtration. The iron content in the leachate is 0.18g/L.

Add sodium sulfide to the leaching solution. The leaching process uses antimony sulfide minerals with an ore content of 5.0%. The temperature is controlled at 25°C and the reaction is stirred for 60 minutes. The liquid and solid are separated by vacuum filtration. After preliminary purification, the iron content in the solution is 0.08g/L. Add activated carbon to the liquid after preliminary iron removal, add 20g of activated carbon per liter of liquid after preliminary iron removal, control the temperature at 25°C and stir for 60 minutes, use vacuum filtration to separate liquid and solid, and the iron content in the liquid after deep purification is 0.009g/L .

After deep iron removal, the liquid is added to the high-pressure reactor, and oxygen is introduced to control the pressure of 0.3MPa. The temperature is controlled at 25°C and the reaction is stirred for 60 minutes. The liquid and solid are separated by vacuum filtration. After low-temperature oxidation, the iron content in the liquid is less than 0.001g/L. After low-temperature oxidation, the liquid is added to the high-pressure reactor, and oxygen is introduced to control the pressure at 1.8MPa, and the temperature is controlled at 110°C to stir and react for 240 minutes. Vacuum suction filtration is used to separate the liquid from the solid. After washing and drying, the precipitated product is a qualified sodium pyroantimonate product. The antimony content is 48.69%, and the iron and arsenic content are both less than 0.001%.

Claims (2)

1. The method for preparing high-quality sodium pyroantimonate by gradient purification and oxidation is characterized by comprising the following steps:

(1) Sodium sulfide leaching

Preparing 10-20g/L sodium hydroxide solution, adding antimony sulfide-containing mineral according to the ratio of liquid volume L to solid weight kg of 1.0-3.0:1, adding sodium sulfide according to the molar ratio of antimony sulfide to sodium sulfide of 2.7-3.3:1, controlling the reaction temperature to be 25 ℃ and stirring for reacting for 10-25min, carrying out liquid-solid separation in a vacuum suction filtration mode, and carrying out a subsequent preliminary iron removal procedure on the leaching solution, wherein leaching residues are used for extracting other valuable metals;

(2) Preliminary iron removal

Adding antimony sulfide-containing minerals with the ore quantity of 1-20% into the leaching solution in the leaching process, controlling the reaction temperature to be 25 ℃ and stirring for reaction for 30-120min, adopting a vacuum filtration mode for liquid-solid separation, and feeding the liquid after preliminary iron removal to a deep iron removal process, and returning the preliminary iron removal slag to leaching;

(3) Deep iron removal

Adding active carbon into the primarily iron-removed liquid, adding 10-30g of active carbon into each liter of primarily iron-removed liquid, controlling the reaction temperature to be 25 ℃, stirring and reacting for 30-120min, performing liquid-solid separation in a vacuum filtration mode, and performing low-temperature pressurized oxidation on the deeply iron-removed liquid and washing deeply iron-removed slag for recycling;

(4) Low temperature pressure oxidation

Adding the solution after deep iron removal into a high-pressure reaction kettle, introducing oxygen, controlling the pressure to be 0.1-0.5MPa, controlling the temperature to be 20-30 ℃ and stirring for reaction for 30-120min, adopting a vacuum filtration mode for liquid-solid separation, sending the solution after low-temperature oxidation to a high-temperature pressurized oxidation process, and sending low-temperature oxidizing slag to a pyrogenic process for smelting antimony to recover antimony;

(5) High temperature pressure oxidation

Adding the low-temperature oxidized liquid into a high-pressure reaction kettle, introducing oxygen, controlling the pressure to be 1.0-2.0MPa, controlling the temperature to be 100-120 ℃ and stirring for reaction for 120-420min, performing liquid-solid separation in a vacuum filtration mode, and washing and drying high-temperature oxidized slag to obtain a qualified sodium pyroantimonate product.

2. The method for preparing high-quality sodium pyroantimonate by gradient purification and oxidation according to claim 1, wherein the method comprises the following steps: the main components of the antimony sulfide-containing mineral are as follows by weight percent: 1.0 to 60.0 percent of Sb and 5.0 to 28.0 percent of S.