Method for recovering and preparing alum from activated clay production waste liquid

Abstract

The invention discloses a method for recovering and preparing alum from activated clay production waste liquid, comprising the following steps of using sulfuric acid, aluminum sulfate in the activatedclay production waste liquid to react with aluminum hydroxide and stronger ammonia water or potassium hydroxide, filtering, evaporating to obtain ammonium alum or potassium alum, purifying, removingimpurities to obtain ammonium alum or potassium alum products with more than 99% of purity. The invention solves the problem existing in the management and recycling method of the activated clay production waste liquid, lowers cost for preparing alum in industry and has the advantages of environment protection, energy conservation and the like.

Description

technical field [0001] The invention relates to the fields of wastewater treatment and inorganic salt preparation, in particular to a method for recovering and preparing alum from activated clay production wastewater. Background technique [0002] Activated clay is mainly used in petroleum refining, decolorization and deodorization of animal and vegetable oils, and purification of insulating oils; it is also a raw material for cosmetics, medicines, and paints. Granular activated clay can be used as catalyst for reforming, isomerization and disproportionation of aromatic hydrocarbons. The preparation method of activated clay from bentonite is mainly wet method at present. The production process includes: hydration of bentonite, activation with sulfuric acid, water washing, drying and pulverization. Since the adsorption capacity of the prepared activated clay to the acid solution can reach 1:1, it needs to be washed repeatedly to make the acid content less than 0.2%, so as t...

AI Technical Summary

Problems solved by technology

Some of these methods have better solved the treatment problem of activated clay production wastewater. For example, the lime neutralization method can neutralize the acidity in the wastewater by adding lime, so that sulfate ions, aluminum ions and iron ions can form calcium sulfate. , Aluminum hydroxide, and iron hydroxide are precipitated and removed, but these precipitates become new solid wastes because they cannot be utilized; some have better solved the problem of recycling resources in activated clay production wastewater, such as using it to decompose china The method of manufacturing industrial water treatment agent aluminum sulfate is to use sulfuric acid in wastewater to decompose china clay, leach the aluminum in china clay into the solution, and then purify and remove impurities, evaporate and crystallize, separate and dry, crush and pack to obtain aluminum sulfate. Although this method effectively utilizes resources such as sulfuric acid and aluminum sulfate in activated clay production wastewater, impurities such as iron ions will affect the quality of the product aluminum sulfate, so they must be removed through purification and impurity removal processes.

At present, the active manganese dioxide method is often used to remove iron, which requires expensive manganese salts, resulting in high processing costs