Method for leaching selenium from cadmium selenide waste

A technology for cadmium selenide and waste, which is applied to chemical instruments and methods, selenium/tellurium compounds, cadmium compounds, etc., can solve the problems of difficult process control, low selenium recovery rate, poor leaching effect, etc., and achieves low cost and selenium recovery. High rate and the effect of improving leaching rate

Active Publication Date: 2018-08-31
FIRST RARE MATERIALS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The root cause lies in the acid leaching process, the reaction is violent, the process is difficult to control, and it is easy to produce highly toxic H 2 Se gas has no industrial application prospect; while the conventional alkaline leaching process has poor leaching effect and low selenium recovery rate

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] 1) Add 396g of CdSe powder passed through a 100-mesh sieve into a 3L high-pressure reactor, add 2376ml of liquid alkali solution with a concentration of 80g / L according to the liquid-solid ratio of 6:1, seal the reactor, start stirring, and control the stirring speed to 200r / min , after heating up to 180°C, start to feed oxygen, control the oxygen partial pressure in the kettle to 0.3Mpa, pass in circulating water to cool to room temperature after reacting for 4 hours, filter the material liquid in the kettle to obtain a stage of oxygen pressure alkali leaching leaching slag and A period of oxygen pressure alkaline leaching solution.

[0030] The quality (dry weight) of the leaching slag of the first stage of oxygen pressure alkaline leaching is 353.6g, and the Se content is 25.3% and the Cd content is 65.7% as detected by ICP-MS.

[0031] 2) Add a section of oxygen pressure alkali leaching leaching residue into a 3L high-pressure reaction kettle, add a liquid alkali so...

Embodiment 2

[0034] 1) Add 396g of CdSe powder passed through a 100-mesh sieve into a 3L high-pressure reactor, add 1980ml of a leaching agent with a sodium hydroxide concentration of 100g / L at a liquid-solid ratio of 5:1, seal the reactor, start stirring, and control The stirring speed is 200r / min, after the temperature rises to 150°C, start to feed oxygen, control the partial pressure of oxygen in the kettle to 0.5Mpa, pass in circulating water after 4 hours of reaction and cool to 40°C, filter the feed liquid in the kettle to obtain a section of oxygen Pressure alkaline leaching leaching slag and one-stage oxygen pressure alkaline leaching leaching solution.

[0035] The quality (dry weight) of the leaching slag from the first stage of oxygen pressure alkaline leaching is 350.4g, and the Se content is 23.9% and the Cd content is 66.3% as detected by ICP-MS.

[0036] 2) Add the leaching slag of a section of oxygen pressure alkali leaching into a 3L high-pressure reactor, and add a liquid...

Embodiment 3

[0040]1) Add 396g of CdSe powder passed through a 100-mesh sieve into a 3L high-pressure reactor, add 1584ml of a leaching agent with a sodium hydroxide concentration of 120g / L at a liquid-solid ratio of 4:1, seal the reactor, start stirring, and control The stirring speed is 200r / min. After the temperature rises to 120°C, oxygen is introduced, and the oxygen partial pressure in the kettle is controlled to be 0.5Mpa. After 4 hours of reaction, circulating water is passed in and cooled to 40°C, and the feed liquid in the kettle is filtered to obtain a section of oxygen Pressure alkaline leaching leaching slag and one-stage oxygen pressure alkaline leaching leaching solution.

[0041] The quality (dry weight) of the leaching slag from the first stage of oxygen pressure alkaline leaching is 355.2g, and the Se content is 26.0% and the Cd content is 65.4% as detected by ICP-MS.

[0042] 2) Add a section of oxygen pressure alkali leaching leaching slag into a 3L high-pressure reacti...

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Abstract

The invention relates to a method for leaching selenium from cadmium selenide waste. The method adopts two-section oxygen pressure alkaline leaching; the cadmium selenide waste is subjected to first-section oxygen pressure alkaline leaching, and the leaching residue of the first-section oxygen pressure alkaline leaching is used as the raw material of second-section oxygen pressure alkaline leaching; the leaching liquid of the second-section oxygen pressure alkaline leaching returns to a leaching agent of the first-section oxygen pressure alkaline leaching; and the first-section oxygen pressure alkaline leaching and second-section oxygen pressure alkaline leaching are both performed in a high-pressure reaction kettle, and oxygen is introduced to both as an oxidizing agent. In the method provided by the invention, selenium in the cadmium selenide waste exists in the leachate totally in a form of sodium selenite, thereby being safe and environment-friendly; and the selenium recovery rate is high, and the cost is low.

Description

technical field [0001] The invention belongs to the field of hydrometallurgy, in particular to a method for leaching selenium from cadmium selenide waste. Background technique [0002] Selenium is an important scattered metal, and its application fields involve electronics, glass, metallurgy, chemical industry, medical care, agriculture and other fields. However, the content of selenium in the earth's crust is only 0.05 ppm, and the distribution is scattered, and the annual supply is limited. Therefore, the recovery of selenium from waste materials has great economic value. [0003] Cadmium selenide (CdSe) has a wide range of applications in photoresistors, solar cells, thin film transistors and microwave amplifiers. A large amount of cadmium selenide waste is produced during the production, processing and use of cadmium selenide, which has a high selenium content and is an important source of selenium recovery. However, there are few reports on the recycling process in t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B19/00C01G11/00
CPCC01B19/008C01G11/00
Inventor 黄华强李琴香陈辉朱刘
Owner FIRST RARE MATERIALS CO LTD
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