Washing method for recycling indium from germanium distillation waste acid

Abstract

A washing method for recovering indium from germanium distilled acid relates to a method for recovering indium from germanium distilled acid, belonging to the technical field of chemical metallurgy, which comprises the following steps of: adding hot water to alkalize slurry for first washing, stirring, washing, standing, pumping the supernatant to leave the base slurry, adding water to the base slurry to carry out second washing until the pH value of the washing water is 6.5-7.0, settling and filtering so as to obtain the oxide with enriched indium. The washing aims at removing alkali, chloride, nitrate, other soluble salts, etc. The oxide with enriched indium is obtained from filtration, and the second washing water is returned to the first washing to be reused. The washing endpoint is that pH is equal to 6.5-7.0 and the content of chloride ions and nitrate ions in the washing water is lower than 50mg / l. The method of the invention is an important step for avoiding secondary pollution in the entire production process and realizing high recovery rate.

Description

technical field [0001] The invention relates to a method for recovering indium from germanium distillation waste acid, especially a washing method thereof, belonging to the technical field of metallurgy and chemical industry. Background technique [0002] Distillation waste acid is the residual acid in the germanium distillation process. Because germanium concentrate or germanium-enriched dust contains a certain amount of indium besides germanium, most of indium is dissolved in the process of distilling germanium with hydrochloric acid system and finally enters the distillation waste. Acid has a certain recovery value. The composition of distillation waste acid is complex, which is reflected in the high acidity, generally containing 6-8mol / l of acid, and containing various impurities such as tin, antimony, bismuth, lead, zinc, magnesium, aluminum, silicon, etc., which makes the recovery of indium a relatively large technology Difficult and uneconomical. Indium recovery tec...

AI Technical Summary

Problems solved by technology

This process is a common indium recovery process, but it has the following disadvantages when it is applied to the recovery of indium from waste acid distillation: (1) the alkali consumption of neutralizing waste acid is large; (2) the sulfuric acid leaching requires high acidity and high temperature. In the process of acid leaching, the insoluble impurities such as lead and other sulfuric acid can only be simply separated, and most of tin, antimony, bismuth, zinc, magnesium, aluminum, silicon, etc. enter the leaching solution. (3) Due to the influence of impurities such as tin, antimony, silicon, etc., the extraction process is prone to third phase, emulsification, etc., which has a serious impact on the extraction; (4) Due to the high chlorine content of the indium-containing slag, the The extraction under the condition of conversion to sulfuric acid system often leads to high residual indium in the raffinate; (5) the extraction agent needs to be regenerated frequently; (6) the concentration of impurities in the indium stripping solution is high, which directly affects the quality of crude indium

Some data show that the recovery rate of indium in this process is high, but the process has not yet been industrialized, and the main disadvantages are as follows: (1) the acid waste gas in the distillation waste acid has an adverse effect on the extraction equipment and the site environment; (2) the distillation waste acid Medium organic matter and silicic acid colloid have adverse effects on the extraction process

[0005] As far as the characteristics of germanium distillation waste acid are concerned, if the traditional sulfuric acid system extraction process is used to recover indium, the following problems need to be solved: (1) high acidity leads to high neutralization costs; (2) tin and arsenic in distillation waste acid , antimony, bismuth, lead, zinc, magnesium, aluminum, silicon, organic matter and other impurities on the extraction of indium; (3) the impact of chlorine on the extraction of the conversion from hydrochloric acid system to sulfuric acid system; (4) hydrochloric acid Environmental pollution problems caused by volatility