Method for preparing 3N refined selenium powder from high-mercury and high-arsenic crude selenium

Abstract

The present application relates to non-ferrous metal extraction metallurgical technical field, especially to a kind of method for preparing 3N fine selenium powder from high mercury and high arsenic crude selenium.In the condition of oxygen, crude selenium is distilled, and selenium dioxide crude product and distillation residue are obtained after condensation;The temperature of the distillation is 500-600 ℃;The content of arsenic in the crude selenium is 500-6000 ppm, and the content of mercury is 500-6000 ppm;The selenium dioxide crude product is dissolved in water to obtain selenious acid crude solution;Chelating agent is added to the selenious acid crude solution, and first solid-liquid separation is carried out after chelation reaction to obtain purified selenious acid solution;The purified selenious acid solution is added to the mixed solution of reducing agent and deflocculant, and second solid-liquid separation is carried out after reduction reaction to obtain 3N fine selenium powder.The selenium prepared by the method has a purity of more than 3N, and the recovery rate of the fine selenium obtained is very high, and the heavy metal content is low.

Description

Technical Field

[0001] This invention relates to the field of non-ferrous metal extraction and metallurgical technology, and in particular to a method for preparing 3N refined selenium powder from crude selenium containing high mercury and high arsenic. Background Technology

[0002] Crude selenium can be recovered from the anode mud of electrolytic copper and waste materials such as flue ash and acid mud from sulfuric acid plants. Due to its production process, crude selenium products generally contain a certain amount of sulfuric acid, as well as a large amount of valuable metals such as arsenic, mercury, tellurium, cadmium, antimony, copper, zinc, nickel, and lead, and precious metals such as gold and silver. It is necessary to go through a purification process to obtain refined selenium products.

[0003] Currently, vacuum distillation purification technology is used in the industrial field. This process has advantages such as high direct metal recovery rate, no need for chemical reagents, and simple operation. However, it has disadvantages such as difficulty in effectively separating tellurium, which has a small temperature difference with selenium volatilization, and excessive levels of impurities such as mercury, arsenic, and tellurium. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for preparing 3N refined selenium powder from crude selenium containing high mercury and high arsenic. The selenium prepared by this method has a purity of 3N or higher, and the recovery rate of the refined selenium is extremely high with low heavy metal content.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing 3N refined selenium powder from crude selenium containing high mercury and high arsenic, comprising the following steps:

[0007] Crude selenium is distilled under oxygen-purified conditions, and crude selenium dioxide and distillation residue are obtained after condensation; the distillation temperature is 500-600℃; the crude selenium contains 500-6000 ppm of arsenic and 500-6000 ppm of mercury.

[0008] The crude selenium dioxide was dissolved in water to obtain a crude selenite solution;

[0009] A chelating agent was added to the crude selenite solution, and after a chelation reaction, a first solid-liquid separation was performed to obtain a purified selenite solution.

[0010] The purified selenite solution was added to a mixed solution of reducing agent and anti-flocculating agent. After a reduction reaction, a second solid-liquid separation was performed to obtain 3N refined selenium powder.

[0011] Preferably, the chelating agent comprises one or more of sodium dimethyl dithiocarbamate and its hydrate, leinak salt, ammonium dithiocarbamate, and ammonium diethyl dithiocarbamate; the mass of the chelating agent is 0.1-5% of the crude selenium dioxide mass.

[0012] Preferably, the chelation reaction takes 0.5 to 3 hours; the chelation reaction is carried out under stirring conditions.

[0013] Preferably, the reducing agent includes one or more of hydrazine hydrate, sodium thiosulfate, thiourea, sodium sulfite, formic acid, hydrazine sulfate, hydrazine hydrochloride, and glucose; the ratio of the actual molar amount of the reducing agent to the theoretical molar amount is 0.8 to 1.5.

[0014] Preferably, the antiflocculator comprises one or more of polyethylene glycol, sodium methylene bis(naphthalene) sulfonate, sodium citrate, and polyvinylpyrrolidone; the mass of the antiflocculator is 0.1-5% of the crude selenium dioxide mass.

[0015] Preferably, the purified selenite solution is added to the mixed solution of reducing agent and anti-flocculation agent by dropwise addition at a rate of 20–1000 mL / min.

[0016] Preferably, the oxygen flow rate is 2 to 10 L / min.

[0017] Preferably, the crude selenium has a selenium content of 80-98% by mass.

[0018] Preferably, the mass of the crude selenium dioxide and the volume of water are 1 kg: 2.5-5 L.

[0019] Preferably, the second solid-liquid separation further includes washing and drying the resulting wet selenium powder.

[0020] This invention provides a method for preparing 3N refined selenium powder from crude selenium containing high levels of mercury and arsenic, comprising the following steps: distilling crude selenium under oxygen-purifying conditions, and obtaining crude selenium dioxide and distillation residue after condensation; the distillation temperature is 500–600°C; the arsenic content in the crude selenium is 500–6000 ppm, and the mercury content is 500–6000 ppm; dissolving the crude selenium dioxide in water to obtain a crude selenite solution; adding a chelating agent to the crude selenite solution, performing a chelation reaction, and then performing a first solid-liquid separation to obtain a purified selenite solution; adding the purified selenite solution to a mixed solution of a reducing agent and a deflocculating agent, performing a reduction reaction, and then performing a second solid-liquid separation to obtain 3N refined selenium powder.

[0021] This invention separates selenium from high-boiling-point impurity metals such as lead, iron, copper, silver, and tellurium through crude selenium distillation oxidation. Simultaneously, arsenic and mercury, which have similar boiling points to selenium, are also partially removed. High-value metals such as gold, silver, arsenic, and mercury are enriched in the slag, facilitating their recovery. Then, crude selenium dioxide is dissolved in water to obtain a crude selenite solution. A chelating agent is added to this solution to form chelates with arsenic and mercury impurity ions, further removing these impurities. Finally, selenite is reduced to elemental selenium in a deflocculation mixture formed by a reducing agent and a deflocculating agent. This invention utilizes a deflocculation reduction system to form an electric double layer on the surface of the generated elemental selenium. The Coulomb repulsion between the electric double layers significantly reduces the attraction for agglomeration of elemental selenium, effectively preventing the agglomeration of selenium flocs from hindering the reduction reaction, thus improving the selenium yield. The small particle size of the selenium powder and the adhesion of the reaction solution to the product surface facilitate subsequent washing and removal. The refined selenium prepared by the method of this invention can be applied to the synthesis of various materials or to provide better raw materials for further purification of selenium. Attached Figure Description

[0022] Figure 1 A flowchart of a method for preparing 3N refined selenium powder according to a specific embodiment of the present invention;

[0023] Figure 2 Image of the dried selenium powder in Example 1;

[0024] Figure 3 The image shows the dried selenium powder in Comparative Example 1. Detailed Implementation

[0025] This invention provides a method for preparing 3N refined selenium powder from crude selenium containing high mercury and high arsenic, comprising the following steps:

[0026] Crude selenium is distilled under oxygen-purified conditions, and crude selenium dioxide and distillation residue are obtained after condensation; the distillation temperature is 500-600℃; the crude selenium contains 500-6000 ppm of arsenic and 500-6000 ppm of mercury.

[0027] The crude selenium dioxide was dissolved in water to obtain a crude selenite solution;

[0028] A chelating agent was added to the crude selenite solution, and after a chelation reaction, a first solid-liquid separation was performed to obtain a purified selenite solution.

[0029] The purified selenite solution was added to a mixed solution of reducing agent and anti-flocculating agent. After a reduction reaction, a second solid-liquid separation was performed to obtain 3N refined selenium powder.

[0030] Unless otherwise specified, all raw materials used in this invention are commercially available products well known in the art.

[0031] This invention involves distilling crude selenium under oxygen-flushing conditions, and obtaining crude selenium dioxide and distillation residue after condensation.

[0032] In this invention, the crude selenium contains various impurities including arsenic, mercury, tellurium, cadmium, antimony, copper, zinc, nickel, lead, gold, silver, sulfur, chlorine, and iodine. The preferred arsenic content in the crude selenium is 500–6000 ppm, the preferred mercury content is 500–6000 ppm, and the preferred lead content is 200–50000 ppm. The preferred selenium content by mass is 80–98%. In specific embodiments, the arsenic content in the crude selenium can be 500, 800, 1032, 1300, 1500, 2000, 2769, 3000, 4000, or 5000 ppm. The content of mercury can be 500, 800, 912, 1200, 1700, 2000, 2500, 2769, 3000, 3500, 4000, 4500 or 5000 ppm, and the content of selenium can be 80%, 85%, 88%, 90.24%, 93%, 95%, 97.49% or 98%; the content of lead in the crude selenium can be 200, 1000, 10000, 13663, 15000, 20000, 30000, 38856, 40000 or 50000 ppm.

[0033] In this invention, the distillation temperature is 500-600°C, and in specific embodiments it can be 500, 520, 540, 560, 580 or 600°C.

[0034] In this invention, the oxygen is preferably high-purity oxygen (O2 purity ≥ 99.995%), and the oxygen flow rate is preferably 2 to 10 L / min, which can be 2, 3.5, 4, 4.5, 6, 8 or 10 L / min in specific embodiments.

[0035] This invention utilizes the differences in boiling points of various metals to separate selenium from impurity metals such as lead, iron, copper, and silver, which have high boiling points, through distillation. At the same time, arsenic and mercury, which have boiling points similar to selenium, are also partially removed. High-value metals such as gold, silver, arsenic, and mercury are enriched in the slag, which is conducive to the recovery of high-value metals. Oxygen is introduced during distillation to oxidize selenium into selenium dioxide.

[0036] After obtaining crude selenium dioxide, the present invention dissolves the crude selenium dioxide in water to obtain a crude selenite solution.

[0037] In this invention, the preferred ratio of crude selenium dioxide to water is 1 kg: 2.5–5 L, and in specific embodiments, it can be 1 kg: 3 L, 1 kg: 4 L, or 1 kg: 5 L. In this invention, the water is preferably deionized water.

[0038] After obtaining the crude selenite solution, the present invention adds a chelating agent to the crude selenite solution, performs a chelation reaction, and then performs a first solid-liquid separation to obtain a purified selenite solution.

[0039] In this invention, the chelating agent preferably includes one or more of sodium dimethyl dithiocarbamate and its hydrate, leynac salt, ammonium dithiocarbamate, and diethyl dithiocarbamate; the mass of the chelating agent is 0.1-5% of the crude selenium dioxide mass, and in specific embodiments it can be 0.1%, 0.5%, 1%, 2%, 3%, 4%, or 5%.

[0040] In this invention, the chelation reaction time is preferably 0.5 to 3 hours, and in specific embodiments it can be 0.5 hours, 1 hour, 2 hours, or 3 hours; the chelation reaction is preferably carried out under stirring conditions. This invention utilizes a chelation reaction to remove residual arsenic and mercury ions.

[0041] In this invention, the first solid-liquid separation is preferably filtration.

[0042] After obtaining the purified selenite solution, the present invention adds the purified selenite solution to a mixed solution of reducing agent and anti-flocculating agent, performs a reduction reaction, and then performs a second solid-liquid separation to obtain 3N refined selenium powder.

[0043] In this invention, the reducing agent preferably includes one or more of hydrazine hydrate, sodium thiosulfate, thiourea, sodium sulfite, formic acid, hydrazine sulfate, hydrazine hydrochloride, and glucose; the ratio of the actual molar amount of the reducing agent to the theoretical molar amount is preferably 0.8 to 1.5 (the theoretical molar amount refers to the amount of reducing agent consumed to theoretically reduce all selenite to elemental selenium), that is, the excess coefficient is preferably 0.8 to 1.5; in specific embodiments, the excess coefficient can be 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, or 1.5. In this invention, when the excess coefficient of the reducing agent is 0.8 to 1, the filtrate B generated from the second solid-liquid separation is reused in the process of dissolving crude selenium dioxide. At this time, the reduction reaction is incomplete, and filtrate B needs to be recycled to prevent a decrease in the yield of refined selenium powder. In this invention, the excess coefficient of the reducing agent in the final reduction reaction must be >1, preferably >1 and ≤1.5.

[0044] In this invention, the antiflocculator preferably includes one or more of polyethylene glycol, sodium methylene bis(naphthalene) sulfonate, sodium citrate, and polyvinylpyrrolidone; the mass of the antiflocculator is preferably 0.1-5% of the crude selenium dioxide mass, and in specific embodiments it can be 0.1%, 0.5%, 1%, 2%, 3%, 4%, or 5%.

[0045] In this invention, water is preferably used as the solvent in the mixed solution of the reducing agent and the anti-flocculating agent. This invention does not have special requirements regarding the concentrations of the reducing agent and the anti-flocculating agent in the mixed solution, as long as they are completely dissolved.

[0046] In this invention, the purified selenite solution is preferably added dropwise; the drop rate is preferably 20-1000 mL / min, and in specific embodiments it can be 50, 100, 200, 300, 400, 500, 600, 700, 800, 900 or 1000 mL / min.

[0047] This invention controls the nucleation and growth rate and crystal size of the reduced selenium element by controlling the addition rate of the purified selenite solution, eliminating the need for a pulverization process, preventing metal impurities caused by equipment wear during pulverization, and reducing the formation of nano-selenium, thus minimizing selenium loss during the subsequent second solid-liquid separation process.

[0048] In this invention, the reduction reaction time is preferably 2 to 8 hours, and in specific embodiments, it can be 2, 4, 6, or 8 hours. In this invention, the reduction reaction is preferably carried out under stirring conditions.

[0049] This invention reduces selenite to elemental selenium in a deflocculation mixture formed by a reducing agent and a deflocculating agent. The deflocculation reduction system forms an electric double layer on the surface of the generated elemental selenium. The Coulomb repulsion between the electric double layers greatly reduces the attraction between elemental selenium particles, effectively preventing the agglomeration of selenium flocs from hindering the reduction reaction, thus improving the selenium yield. The selenium powder has a small particle size, and the reaction solution adheres to the surface of the product, which is beneficial for subsequent washing and removal.

[0050] It is worth noting that the present invention requires the purified selenite solution to be added to the mixed solution of the reducing agent and the anti-flocculation agent in order to achieve the anti-flocculation effect. If the order of addition is changed, the above effect cannot be achieved.

[0051] The present invention does not have any special requirements for the second solid-liquid separation method; any solid-liquid separation method known in the art is acceptable, such as vacuum filtration.

[0052] After completing the second solid-liquid separation, the present invention preferably further includes washing and drying the obtained wet selenium powder. In this invention, the washing is preferably performed 2 to 3 times. The reducing agent and anti-flocculating agent used in this invention adhere to the surface of elemental selenium and are easily removed by washing with water, preventing the introduction of new metallic impurities.

[0053] In this invention, when the excess coefficient of the reducing agent is 0.8 to 1, the washing solution obtained after water washing is preferably reused in the process of dissolving crude selenium dioxide. Only when the excess coefficient is ≤1 will the recycled solution not contain the reducing agent, and will selenite not be reduced when reused in the process of dissolving crude selenium dioxide. Otherwise, a large amount of selenite will be reduced and removed along with metal impurities, resulting in a low selenium yield.

[0054] The waste solution produced by this invention can be recycled and does not generate wastewater.

[0055] Figure 1 This is a flowchart illustrating a specific embodiment of the method for preparing 3N refined selenium powder provided by the present invention. Figure 1 As shown, this invention involves distilling crude selenium under oxygen-flushing conditions, obtaining crude selenium dioxide and distillation residue after condensation; dissolving the crude selenium dioxide in water to obtain a crude selenite solution; adding a chelating agent to the crude selenite solution, performing a chelation reaction, followed by a first filtration to obtain a purified selenite solution and filtrate A; adding the purified selenite solution to a mixed solution of a reducing agent and a deflocculating agent, performing a reduction reaction, followed by a second filtration to obtain wet selenium powder and filtrate B; washing and drying the wet selenium powder to obtain 3N refined selenium powder. When the excess coefficient of the reducing agent is 0.8–1, the washing liquid obtained after washing and filtrate B from the second filtration are reused in the process of dissolving crude selenium dioxide.

[0056] In this invention, the arsenic content in the 3N refined selenium powder is preferably less than 5 ppm, the mercury content is preferably less than 5 ppm, and the lead content is preferably less than 6 ppm.

[0057] The following detailed description of the method for preparing 3N refined selenium powder from crude selenium containing high mercury and high arsenic provided by the present invention, with reference to specific embodiments, is not intended to limit the scope of protection of the present invention.

[0058] Example 1

[0059] A method for preparing 3N refined selenium powder from crude selenium containing high mercury and high arsenic comprises the following steps:

[0060] S1: 1 kg of crude selenium No. 1 with a selenium content of 97.488998% was distilled at 580℃ while high-purity oxygen was introduced for oxidation at a rate of 4.5 L / min. After condensation, 1301.48 g of crude selenium dioxide and 26.06 g of distillation residue were obtained. The selenium dioxide content was analyzed to be 98.04%.

[0061] S2: Dissolve 100g of crude selenium dioxide obtained in S1 in 500mL of deionized water to obtain a crude selenite solution;

[0062] S3: Add 0.5g of ammonium diethyldithiocarbamate to the crude selenite solution of S2, stir thoroughly for 3 hours, and then filter to obtain purified selenite solution and filtrate A;

[0063] S4: The purified selenite solution obtained in S3 was added at a rate of 50 mL / min to a mixed solution of hydrazine sulfate with an excess coefficient of 1.5 and 0.5 g of sodium methylene bisnaphthalene sulfonate (volume of 150 mL). After stirring thoroughly for 8 h, the mixture was filtered to obtain filtrate B and wet selenium powder.

[0064] S5: Wash the wet selenium powder obtained in S4 three times with deionized water, filter and dry to obtain 68.35g of the target product refined selenium powder.

[0065] The yield of refined selenium was calculated to be 91.24% based on the amount of refined selenium powder obtained from S5 and the amount of selenium in crude selenium, after reducing all the selenium dioxide solid obtained from S1.

[0066] Example 2

[0067] A method for preparing 3N refined selenium powder from crude selenium containing high mercury and high arsenic comprises the following steps:

[0068] S1: 1 kg of crude selenium No. 1 with a selenium content of 97.488998% was distilled at 580℃ while high-purity oxygen was introduced for oxidation at a rate of 4.5 L / min. After condensation, 1301.48 g of crude selenium dioxide and 26.06 g of distillation residue were obtained. The selenium dioxide content was analyzed to be 98.04%.

[0069] S2: Dissolve 100g of crude selenium dioxide obtained in S1 in 300mL of deionized water to obtain a crude selenite solution;

[0070] S3: Add 0.5g of ammonium dithiocarbamate to the crude selenite solution obtained in S2, stir thoroughly for 2 hours, and then filter to obtain purified selenite solution and filtrate A.

[0071] S4: The purified selenite solution obtained in S3 was added at a rate of 200 mL / min to a mixed solution of hydrazine hydrochloride with an excess coefficient of 1.1 and 0.5 g sodium citrate (volume of 300 mL). After stirring thoroughly for 4 h, the mixture was filtered to obtain filtrate B and wet selenium powder.

[0072] S5: Wash the wet selenium powder from S4 twice with deionized water, filter and dry to obtain 68.05g of the target product refined selenium powder.

[0073] The yield of refined selenium was calculated to be 90.83% based on the amount of refined selenium powder obtained from S5 and the amount of selenium in crude selenium, after reducing all the selenium dioxide solid obtained from S1.

[0074] Example 3

[0075] A method for preparing 3N refined selenium powder from crude selenium containing high mercury and high arsenic comprises the following steps:

[0076] S1: 1 kg of crude selenium No. 2 with a selenium content of 90.24% was distilled at 500℃ while high-purity oxygen was introduced for oxidation at a rate of 3.5 L / min. After condensation, 1204.71 g of selenium dioxide solid and 98.60 g of distillation residue were obtained. The selenium dioxide content was analyzed to be 96.94%.

[0077] S2: Dissolve 100g of crude selenium dioxide from step S1 in 500mL of deionized water to obtain a crude selenite solution;

[0078] S3: Add 0.5g of diethyldithiocarbamate to S2, stir thoroughly for 3 hours, and then filter to obtain purified selenite solution and filtrate A;

[0079] S4: The purified selenite solution obtained in S3 was added to a mixed solution (volume of 200 mL) of thiourea and 0.5 g polyvinylpyrrolidone with a reaction excess coefficient of 1.2 at a rate of 100 mL / min. After stirring thoroughly for 4 h, the mixture was filtered to obtain filtrate B and wet selenium powder.

[0080] S5: Wash the wet selenium powder from S4 twice with deionized water, filter and dry to obtain 67.60g of the target product refined selenium powder.

[0081] The yield of refined selenium was calculated to be 90.21% based on the amount of refined selenium powder obtained from S5 and the amount of selenium in crude selenium, after reducing all the selenium dioxide solid obtained from S1.

[0082] Comparative Example 1

[0083] The difference from Example 1 is that no anti-flocculation agent was added in step S4, and the product was filtered and dried to obtain 67.55g of refined selenium powder.

[0084] The yield of refined selenium was calculated based on the amount of refined selenium powder obtained from S5. The amount of refined selenium powder obtained from reducing all the selenium dioxide solid obtained from S1 was compared with the amount of selenium in crude selenium, resulting in a yield of 89.15%.

[0085] Figure 2 Image of the dried selenium powder in Example 1; Figure 3 The image shows the dried selenium powder from Comparative Example 1. (Comparison) Figure 2 and Figure 3 It can be seen that the introduction of anti-flocculation agent can prevent the selenium flocs generated by the reduction of selenite acid from agglomerating, which is conducive to the full contact between the reducing agent and the selenite acid solution, resulting in a more thorough reaction and thus improving the yield of refined selenium powder.

[0086] Comparative Example 2

[0087] The difference from Example 1 is that no chelating agent was added in step S3, and the product was filtered and dried to obtain 69.04g of refined selenium powder.

[0088] The yield of refined selenium was calculated to be 90.48% based on the amount of refined selenium powder obtained from S5 and the amount of selenium in crude selenium, after reducing all the selenium dioxide solid obtained from S1.

[0089] The impurity components of the crude selenium used in each example and comparative example, as well as the refined selenium powder prepared, were analyzed by glow discharge mass spectrometry. The analysis results are detailed in Table 1.

[0090] Table 1. Composition of crude and refined selenium powder used in each embodiment and comparative example.

[0091]

[0092] As shown in Table 1, the content of arsenic, mercury and lead in the refined selenium powder prepared by the method of the present invention is greatly reduced. However, in Comparative Example 1, since no anti-flocculation agent was added, the generated selenium flocs encapsulated the impurities and reactants in the reaction solution, making it difficult to rinse with deionized water. Therefore, the impurity content in the refined selenium powder was higher than that in the example. In Comparative Example 2, since no chelating agent was added, the content of arsenic, mercury and lead impurities was still relatively high.

[0093] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing 3N refined selenium powder from crude selenium containing high mercury and high arsenic, characterized in that, Includes the following steps: Crude selenium is distilled under oxygen-flushing conditions, and after condensation, crude selenium dioxide and distillation residue are obtained; the distillation temperature is 500-600℃; the crude selenium contains 500-6000 ppm of arsenic and 500-6000 ppm of mercury; and the mass content of selenium in the crude selenium is 80-98%. The crude selenium dioxide was dissolved in water to obtain a crude selenite solution; A chelating agent was added to the crude selenite solution, and after a chelation reaction, a first solid-liquid separation was performed to obtain a purified selenite solution. The purified selenite solution was added to a mixed solution of reducing agent and anti-flocculating agent. After a reduction reaction, a second solid-liquid separation was performed to obtain 3N refined selenium powder. The chelating agent comprises one or more of sodium dimethyl dithiocarbamate and its hydrate, leinak salt, ammonium dithiocarbamate, and diethyl dithiocarbamate; the mass of the chelating agent is 0.1-5% of the crude selenium dioxide mass. The antiflocculator includes one or more of polyethylene glycol, sodium citrate, and polyvinylpyrrolidone; the mass of the antiflocculator is 0.1-5% of the crude selenium dioxide mass.

2. The method according to claim 1, characterized in that, The chelation reaction takes 0.5 to 3 hours and is carried out under stirring conditions.

3. The method according to claim 1, characterized in that, The reducing agent includes one or more of hydrazine hydrate, sodium thiosulfate, thiourea, sodium sulfite, formic acid, hydrazine sulfate, hydrazine hydrochloride, and glucose; the ratio of the actual molar amount of the reducing agent to the theoretical molar amount is 0.8 to 1.

5.

4. The method according to claim 1, characterized in that, The purified selenite solution was added to the mixed solution of reducing agent and anti-flocculation agent by dripping at a rate of 20-1000 mL / min.

5. The method according to claim 1, characterized in that, The oxygen flow rate is 2~10 L / min.

6. The method according to claim 1, characterized in that, The mass of the crude selenium dioxide and the volume of water are 1 kg: 2.5~5 L.

7. The method according to claim 1, characterized in that, The second solid-liquid separation process also includes washing and drying the resulting wet selenium powder.

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