Treatment process method of chrome slag

Abstract

The invention relates to the field of heavy metal recovery and treatment, and discloses a treatment process method of chrome slag. The method comprises the steps that: chrome slag is subjected to ball milling; the milled chrome slag is leached by using sulfuric acid, such that water-soluble sodium chromate tetrahydrate, calcium chromate, chrome calcium aluminate, basic iron chromate, chemically adsorbed hexavalent chromium, and dicalcium silicate-calcium chromate and iron calcium aluminate-calcium chromate which are hard to dissolve in water and can be dissolved in acid can be obtained by leaching. The reaction can be shown as: Ca2SiO4-CaCrO4+H2SO4+(x-1)H2O; CaSiO3.xH2O+CaCrO4+CaSO4, 4CaO.Al2O3Fe2O3-CaCrO4+H2SO4+(y-1)H2O; and CaO.Al2O3.yH2O+2CaO.Fe2O3+CaCrO4+CaSO4. A mixed material obtained by leaching is subjected to solid-liquid separation; a filter residue is washed by using water; solid-liquid separation is carried out again; a filtrate is delivered through an absorption exchange column loaded with a heavy metal absorption material; soluble chrome is absorbed and enriched in the surface of the heavy metal absorption material; backwashing and desorption are carried out, such that a concentrated chrome solution is obtained; and the solution is treated in a electrodeposition process, and chrome is recovered. With the technical scheme provided by the embodiment of the invention, highly toxic chromium element in the chrome slag can be removed, and heavy metal can be recovered and utilized. The method is beneficial for environment protection.

Description

technical field [0001] The invention relates to the field of heavy metal recycling and processing, in particular to a processing method for chromium slag. Background technique [0002] Chromium slag is a granular hard sintered solid waste with different particle sizes, and its appearance is mostly earthy gray or off-white. Due to the different raw materials and processes used, it usually contains Ca, Mg, Al, Fe, Si, Cr, Hg, Ni, etc., and is generally alkaline. There are five main forms of chromium in chromium slag: [0003] (1) Water-soluble state, hexavalent Cr generally exists in the form of chromate, and its solubility in water is relatively large. [0004] (2) Acid-soluble state, a large number of dead-burned alkaline minerals in chromium slag dissolve after encountering acid. The chromium wrapped in it is released, and this part of chromium is generally hexavalent. [0005] (3) In the bonded state, chromium that exists in the form of oxides with iron, manganese and ...

AI Technical Summary

Problems solved by technology

The biggest disadvantage of this method is that the survival rate of bacteria is low, and the propagation speed of functional bacteria is slow, and the incubation time generally takes more than 24 hours. ability, the water treated by this method is difficult to reuse

At present, most of the biological methods are only in the research stage of laboratory or pilot scale, and a large amount of chromium slag has not been treated.

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