A method for recycling and processing arsenic slag resources by freezing and separating arsenic and alkali in the immersion solution of alkali slag

Abstract

The invention relates to a method for recycling and treating arsenic slag resources by freezing and separating arsenic and alkali in alkaline slag water extract. The method comprises the following steps of adding water into alkaline slag, pulping, leaching with water, introducing CO<2> gas to convert NaOH in the slurry into Na<2>CO<3>, evaporating and concentrating the separated Na<2>CO<3>-containing arsenic alkaline water extract, cooling, freezing and crystallizing, dissolving the separated wet crystals, cooling, freezing and recrystallizing again to obtain sodium carbonate, concentrating the separated arsenic-containing mother liquor, carrying out secondary freezing crystallization treatment, precipitating arsenic by using a Na<2>S saturated aqueous solution, maintaining the pH value at1-2 by using H<2>SO<4>, adding pulverized coal into filter residues separated from an arsenic precipitation mixed solution, and carrying out oxidation incineration to obtain As<2>O<3>, and convertingthe filtrate with lime. According to the method, arsenic and alkali in the alkaline slag water extract are separated through freezing crystallization, Na<2>CO<3>.10H<2>O is obtained through freezingrecrystallization, and Na<2>S is used for precipitating arsenic, so that arsenic slag resources can be well recycled.

Description

technical field [0001] The invention relates to inorganic chemical industry, non-ferrous smelting and environmental protection technology, in particular to a method for recycling and treating arsenic slag resources by using freezing to separate arsenic and alkali in alkali slag water immersion liquid. Background technique [0002] In the antimony industry of non-ferrous metals, arsenic-alkali slag with high antimony content is often produced during de-arsenic refining of crude antimony. The typical composition of this alkali slag is: Sb: 15-30%, As: 2-6%, Na 2 O: 30-40%, S: 2-4%, the general yield accounts for 15-25% of antimony output, commonly known as primary alkali slag. Some people use the primary alkali slag as a flux and raw material ingredients, mix it with various antimony and arsenic-containing baghouse dust and soda ash, put it into the reverberatory furnace and mix it with reduced coal powder for reduction and smelting again, and produce a rough antimony alloy wi...

AI Technical Summary

Problems solved by technology

The latter focuses on the use of alkali with CO 2 The gas is all converted into sodium bicarbonate, which is separated from the water immersion solution by taking advantage of its low solubility. However, it has not been widely used due to high production costs, high residual alkali, low alkali recovery rate, and poor production efficiency.

Some people have made in-depth studies on the characteristics of the arsenic-alkali separation in the water immersion liquid that affects the freezing and separation of alkali slag, and proposed a scheme of using ultrasonic waves and electromagnetic fields to exert influence, but no feasible and effective method has been formed for the harmless open-circuit treatment of arsenic in alkali slag.

Moreover, there are few professional studies on secondary alkali slag with large production scale

Images