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CN-121974305-A - Method for efficiently reducing selenium simple substance from selenium-containing leaching solution based on ferrous sulfate

CN121974305ACN 121974305 ACN121974305 ACN 121974305ACN-121974305-A

Abstract

The invention discloses a method for efficiently reducing selenium simple substance from selenium-containing leaching solution based on ferrous sulfate, which comprises the steps of taking selenium-containing leaching solution obtained through oxidation acid leaching, regulating the acidity of the leaching solution to 0.5-1.1 mol/L, adding ferrous sulfate into the selenium-containing leaching solution subjected to acid regulation according to the liquid-solid ratio of 2mL to (1.0-1.4) g for reduction reaction, wherein the reduction reaction temperature is 70-90 ℃, the reduction reaction time is 40-80 min, obtaining a reaction product I, separating precipitate of the reaction product I, washing and drying, and obtaining the selenium simple substance. The method adopts ferrous sulfite to reduce and extract selenium simple substance from the selenium-containing leaching solution, under the limiting condition, the reduction rate of selenium can reach more than 91 percent, and under the optimizing condition, the reduction rate of selenium can reach 95.87 percent, which is obviously superior to the prior art such as a microbiological method.

Inventors

  • LI XI
  • YE YOUMING
  • WEI JIAN
  • GUO QIONG
  • WEI YOUHUAN
  • ZENG JUN
  • XIE XUEZHEN

Assignees

  • 广西科技师范学院

Dates

Publication Date
20260505
Application Date
20251231

Claims (7)

  1. 1. A method for efficiently reducing selenium simple substance from selenium-containing leaching solution based on ferrous sulfate is characterized by taking selenium-containing leaching solution obtained through oxidation acid leaching, adjusting the acidity of the selenium-containing leaching solution to 0.5-1.1 mol/L, adding ferrous sulfate into the selenium-containing leaching solution subjected to acid adjustment according to the liquid-solid ratio of 2mL to (1.0-1.4) g for reduction reaction, wherein the reduction reaction temperature is 70-90 ℃ and the reduction reaction time is 40-80 min, obtaining a reaction product I, separating precipitate of the reaction product I, and washing and drying to obtain the selenium simple substance.
  2. 2. The method for efficiently reducing elemental selenium from a selenium-containing leachate based on ferrous sulfate as claimed in claim 1, wherein the acidity of the selenium-containing leachate is 0.7-0.9 mol/L, the reduction reaction temperature is 80-90 ℃, and the reduction reaction time is 50-80 min.
  3. 3. The method for efficiently reducing selenium simple substance from selenium-containing leaching solution based on ferrous sulfate according to claim 2, wherein the liquid-solid ratio is 2mL to (1.0-1.2) g, and the reduction reaction time is 50-60 min.
  4. 4. The method for efficiently reducing elemental selenium from a selenium-containing leachate based on ferrous sulfate as claimed in claim 3, wherein the acidity of the selenium-containing leachate is 0.7mol/L, the liquid-solid ratio is 2 mL:1.0 g, the reduction reaction temperature is 80 ℃, and the reduction reaction time is 60min.
  5. 5. The method for efficiently reducing selenium simple substance from selenium-containing leaching solution based on ferrous sulfate, which is characterized in that the oxidation acid leaching is carried out by uniformly mixing selenate mud powder and manganese dioxide according to the mass ratio of 1:2.2-2.5 to obtain a mixture, adding 6-7 mol/L mixed acid into the mixture according to the solid-to-liquid ratio of 1 g:10-30 mL, stirring and leaching at 60-80 ℃ for 40-60 min to obtain a reaction product II, and filtering the reaction product II to obtain the selenium-containing leaching solution.
  6. 6. The method for efficiently reducing elemental selenium from a selenium-containing leaching solution based on ferrous sulfate as set forth in claim 5, wherein the selenium-containing mud is flue gas generated in a jamesonite smelting process, and is obtained by water washing and trapping, and the components of the selenium-containing mud include Se, pb, as, ag and Te, wherein the mass content of Se is not less than 70%.
  7. 7. The method for efficiently reducing elemental selenium from a selenium-containing leachate based on ferrous sulfate as claimed in claim 5, wherein the mixed acid is formed by mixing hydrochloric acid and sulfuric acid, and the addition volume ratio of the hydrochloric acid to the sulfuric acid is 1:1.

Description

Method for efficiently reducing selenium simple substance from selenium-containing leaching solution based on ferrous sulfate Technical Field The invention belongs to the field of recycling of selenate mud, and particularly relates to a method for efficiently reducing selenium simple substance from selenium-containing leaching solution based on ferrous sulfate. Background Selenium is a trace element necessary for human body, is also an important strategic key metal mineral resource in China, and is widely applied to the fields of electronics, photovoltaics, medicines and the like. In the smelting process of nonferrous metals such as lead-antimony ore, selenium volatilizes along with flue gas, and the selenium is deposited in the selenium-containing acid mud after wet dust collection. If the selenate mud is directly returned to a smelting system, selenium is continuously enriched in the system to deteriorate smelting indexes, and if the selenate mud is piled up for a long time, selenium and other harmful metals (such As Pb and As) can be leached into soil or water along with rainwater to cause serious environmental pollution. Therefore, the recovery of selenium from the selenate mud has important economic value and environmental protection significance. At present, the selenium recovery process in the selenate mud mainly comprises (1) an oxidation roasting-sulfur dioxide reduction method, which needs high-temperature roasting, has high energy consumption and is easy to cause secondary pollution by sulfur dioxide, (2) a pressurized oxygen leaching-extraction-iron powder reduction method, which has complex steps, high requirements on equipment under the pressurized condition and high cost, (3) an ammonium sulfite reduction method, which has poor stability and is easy to decompose and possibly causes residual ammonium salt in the product, (4) a microbial reduction method, which utilizes anaerobic strains to reduce selenate ions, has environmental friendliness, has long reaction period (usually needs days), has strict control on temperature, pH and other conditions, and is difficult to industrially popularize. The existing wet extraction process is as follows: 1. The preparation method of extracting selenium from selenium-containing waste at normal temperature, europe Gao Yu and the like propose that selenium oxide is oxidized by hydrogen peroxide under the strong acid condition, and then the selenium is reduced by hydrazine hydrate after the impurity is removed by sodium chloride and ammonia water, so that the selenium simple substance is obtained, and the purity of the product is about 90 percent. Although the method is carried out at normal temperature, high-temperature energy consumption is avoided, the current market price of hydrazine hydrate (80% specification) used in the process is about ‌ yuan/ton to 18500 yuan/ton ‌, so that the comprehensive recovery cost is high. 2. And (3) researching a process for recovering selenium from the selenium-rich acid mud, pan Xijian and the like, leaching the selenium by adopting hydrogen peroxide oxidation alkali, separating mercury by adopting sodium hypochlorite oxidation acid leaching, and finally reducing the selenium by using sodium sulfite. The method also needs to control the results of raw materials and products in the three working procedures, has the problem of unstable process, is difficult to realize industrialization effectively, and adopts various raw materials such as hydrogen peroxide, sodium hydroxide, hydrochloric acid, sodium hypochlorite, sodium sulfide, sulfuric acid, sodium sulfite and the like, so that the cost of comprehensive recovery is higher. 3. The research adopts a calcium-adding selenium-fixing method to conduct research on removing mercury and fixing selenium on acid mud, and tests such as acid leaching and the like on roasting residues. Experimental results show that under the conditions that the lime addition amount is 80% of the acid sludge amount, the roasting temperature is 500 ℃ and the roasting time is 2 hours, the mercury volatilization rate and the selenium fixation rate respectively reach 99.03% and 85.69%, under the conditions that the liquid-solid ratio is 5:1, the sulfuric acid mass concentration is 350g/L, 6ml of nitric acid is added to each liter of leaching liquid, the leaching temperature is 90 ℃, and the leaching time is 3 hours, the leaching rate of selenium in roasting slag can reach 91.03%. The study involves high temperature calcination, which has the problem of high energy consumption. 4. Test research on extracting selenium from selenate mud, wang Xiaowu and the like, researches on separating selenium and mercury from selenate mud by adopting a calcium-adding selenium-fixing mercury-removing wet selenium-extracting process, examines the influence of roasting temperature, roasting time and mass ratio of materials and lime on the selenium-fixing rate, and the influence of sulfuric acid mass concentration and leachin