Method for solidifying arsenic-calcium residue or arsenic-iron residue

Abstract

The invention discloses a method for solidifying arsenic-calcium residue or arsenic-iron residue, comprising the following steps of: (1) drying arsenic-containing waste residue under 150-200 DEG C, and removing most moisture in the waste residue, so that the water content of arsenic residue is less than 20%; and if necessary, oxidizing the waste residue before drying; and (2) carrying out oxidizing roasting on the dried arsenic-containing waste residue under 600-1000 DEG C, wherein the roasting time is 1-3hours, and blowing in air or oxygen in the manner of natural air charge or initiative air supply in the process of roasting. The As concentration of leaching agent of arsenic-calcium residue or arsenic-iron residue treated by the method disclosed by the invention is much less than the nationally-regulated limiting value (5mg / L), so that the arsenic can be effectively solidified, a treatment technology is compact in technological process, the operation is easy to control, and the method is lower in treatment cost.

Description

【Technical field】 [0001] The invention relates to a harmless treatment method for solid hazardous waste, in particular to a solidification treatment method for arsenic-calcium slag or arsenic-iron slag. 【Background technique】 [0002] With the development of industries such as metallurgy and chemical industry and the development of lean mines, more and more harmful elements have entered into industrial wastewater, such as arsenic, lead, zinc, mercury, copper, etc. These harmful elements will cause great harm to the water body itself. harm, and also threaten the safety of humans and livestock, especially arsenic and its compounds are highly toxic carcinogens, if not controlled, it will easily cause extremely serious pollution to the environment, if arsenic pollutes water bodies and soil , will eventually enter the human body through the food chain, surface water and groundwater and endanger human health. Therefore, we must treat arsenic-containing wastewater before it can be ...

AI Technical Summary

Problems solved by technology

[0003] At present, the treatment methods of arsenic slag mainly include: (1) carry out comprehensive utilization to form arsenic products, such as white arsenic method, metal arsenic method, etc. These methods have problems such as low arsenic recovery rate and poor working conditions, while arsenic products The limited market space limits the application of this type of method in the treatment of arsenic slag; (2) Carry out harmless fixation treatment, using physical and chemical methods to fix or contain harmful solid waste in an inert solid matrix to make it appear chemically A harmless treatment method for stability or sealing

At present, the commonly used stabilization methods for treating arsenic-containing waste residues at home and abroad include cement solidification, organic polymer solidification, plastic material solidification, and melt solidification; the cement solidification method has a high arsenic leaching rate in the cement solidified body, and coating treatment is required. The disadvantages of cement solidification are relatively high compatibilization; the disadvantage of organic polymer solidification is that it is not safe enough. Sometimes the strong acid catalyst used will dissolve heavy metals during the polymerization process, and the solidified body is loose, so it needs to be put into a container for disposal, which increases the disposal cost. The disadvantage of the plastic material solidification method is that the solidified substrate is flammable, the thermoplastic material is expensive, the operation is complicated, and the equipment cost is high; the disadvantage of the melt solidification method is that the process is complicated, the equipment material requirements are high, and the processing cost is high

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