Method for removing tellurium from coarse selenium

A technology of coarse selenium and selenium powder, applied in the direction of elemental selenium/tellurium, etc., can solve the problems of polluted environment, low recovery rate of selenium, serious problems, etc.

Inactive Publication Date: 2005-10-26
GUANGZHOU RES INST OF NON FERROUS METALS
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AI Technical Summary

Problems solved by technology

In the whole production, the recovery rate of selenium reaches 85-90%, and the recovery rate of tellurium reaches about 90%. This method has a low recovery rate of selenium and high cost
At the same time, due to the escape of selenium dioxide and the release of a large amount of sulfur dioxide, the environment is polluted and the equipment is severely corroded.

Method used

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  • Method for removing tellurium from coarse selenium

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0007] 100g of crude selenium containing 90% of selenium and 7.5% of tellurium was added with a concentration of 40% sodium hydroxide solution, the solid-to-liquid ratio was 1:2.5, the reaction temperature was 90°C, the reaction time was 4 hours, the volume was diluted 0.75 times, and filtered. The filtrate was added to the oxidation equipment and oxidized with oxygen. The oxidation time was 30 hours. The pH of the solution was adjusted to 12 with dilute sulfuric acid to obtain selenium powder precipitation. After filtering, washing and drying, 87.27g of selenium powder was obtained. The pH of the filtrate was adjusted to 5 with dilute sulfuric acid to obtain tellurium dioxide precipitate. The recoveries of selenium and tellurium are 96% and 95.5% respectively, and the selenium powder contains 99% selenium and 0.35% tellurium.

Embodiment 2

[0009] Same as Example 1. 100g crude selenium contains 82.5% selenium, 12.6% tellurium, the concentration of sodium hydroxide solution is 30%, the solid-to-liquid ratio is 1: 1.5, the reaction temperature is 85°C, the reaction time is 5 hours, the volume is diluted by 1 time, and filtered , the filtrate was oxidized by air for 35 hours, and the pH of the solution was adjusted to 13 with dilute sulfuric acid to obtain selenium powder precipitation, and the pH of the filtrate was adjusted to 4.5 to obtain tellurium dioxide precipitation. The selenium powder weighs 81.4g after washing and drying, and the selenium powder contains 96.4% of selenium and 0.43% of tellurium. The recoveries of selenium and tellurium were 95.1% and 95.8%, respectively.

Embodiment 3

[0011] Same as Example 1. 100g thick selenium contains 80.2% selenium, 17.5% tellurium, the concentration of sodium hydroxide solution is 35%, the solid-to-liquid ratio is 1:2, the reaction temperature is 75°C, the reaction time is 6 hours, the volume is diluted by 0.5 times, and filtered , the filtrate was oxidized by oxygen for 25 hours, the pH of the solution was adjusted to 13 with dilute sulfuric acid to obtain selenium powder precipitation, and the pH of the filtrate was adjusted to 5 to obtain tellurium dioxide precipitation. The selenium powder weighs 80.54g after being washed and dried, and contains 95.6% of selenium and 0.5% of tellurium. The recoveries of selenium and tellurium were 96% and 96.2%, respectively.

[0012] The recovery rates of selenium and tellurium in the method of the invention are higher than those of the oxygen combustion-reduction method. The environment pollution and equipment corrosion caused by the escape of selenium dioxide and the release o...

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Abstract

The present invention relates to a method for removing tellurium from crude selenium. Said method is characterized by that it includes the following steps: adding crude selenium into sodium hydroxide solution to make reaction, then making dilution and filtration, introducing air or oxygen gas into the filtrate to make oxidation, using dilute sulfuric acid to regulate pH of solution so as to obtain selenium powder precipitate, filtering, washing and drying so as to obtain selenium powder. The selenium percent recovery can be up to above 95%, purity of selenuim is 95-99% and tellurium content is less than or equal to 0.5%.

Description

technical field [0001] The invention relates to a method for recovering and purifying chemical elements. Background technique [0002] Selenium is a rare metal element, and it is difficult to form an independent ore deposit with industrial mining value. Therefore, selenium is comprehensively recovered from the by-products of the non-ferrous metal smelting process. It is mainly extracted from anode sludge such as copper, nickel, lead, etc., as well as flue gas dust sludge or leached sludge from the production of sulfuric acid or pulp. Selenium and tellurium elements have similar properties and are often associated. The recovery of selenium often adopts the sulfuration roasting method, and the selenium content in the obtained crude selenium is 80-95%, and the element tellurium content is 5-20%. [0003] At present, the main method for industrially removing tellurium from crude selenium is the oxygen combustion-reduction method, that is, under high temperature conditions, oxy...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B19/02
Inventor 顾珩李杏英
Owner GUANGZHOU RES INST OF NON FERROUS METALS
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