Method for combined utilization of iron-based pigment wastewater and reduced titanium tail gas

Abstract

The invention discloses a method for combined utilization of iron-based pigment wastewater and reduced titanium tail gas, which comprises the following steps: S1, carrying out solid-liquid separation on iron-based pigment mother liquor through a ceramic membrane to obtain mother liquor clear liquid; the iron-based pigment washing liquid is concentrated through a ceramic membrane and a reverse osmosis membrane in sequence, and reverse osmosis concentrated liquid is obtained; s2, adding a calcium-containing alkaline substance into the mother liquor clear liquid and the reverse osmosis concentrated liquid, adjusting the pH value to 9.5-10.5, and then carrying out filter pressing to obtain a gypsum precipitate and a filtrate; s3, adjusting the pH value of the filtrate to be greater than 11, and then carrying out contact reaction on the filtrate and the purified reduced titanium tail gas until no new precipitate is generated; and S4, carrying out ceramic membrane separation on the reacted material again, and carrying out MVR concentration on the separated clear liquid. The iron-based pigment waste liquid and the reduced titanium tail gas are effectively utilized, pollution to the environment is reduced, and economic value is created.

Description

technical field [0001] The invention belongs to the technical field of preparation of iron-based pigment wastewater, and in particular relates to a method for combined utilization of iron-based pigment wastewater and reduced titanium tail gas. Background technique [0002] During the production of sulfuric acid titanium dioxide, a large amount of by-product ferrous sulfate will be produced. At present, for the treatment of ferrous sulfate, the usual treatment method is to use ferrous sulfate to produce iron-based pigments. In the production process of iron-based pigments, after the finished product is removed from the mother liquor, the mother liquor wastewater is acidic and has a high salt content, which cannot meet the requirements of direct discharge and needs further treatment. For example, the patent CN 108557877A describes a co-production process of titanium dioxide, iron red, and polyferrous sulfate chloride, in which sodium hydroxide is added to a saturated ferrous s...

AI Technical Summary

Problems solved by technology

The iron-based pigment mother liquor contains a large amount of salt and acidity. The common treatment method is alkali neutralization, but the use of caustic soda for neutralization requires a large amount of alkali, which will result in higher costs.

Although the salt concentration and acidity of the iron-based pigment washing water are lower than those of the iron-based pigment mother liquor, direct discharge will still cause certain pollution to the environment

[0003] In addition, a large amount of CO is produced in the exhaust gas of the reducing titanium rotary kiln in another stage of titanium dioxide production. 2 If the gas is not utilized for direct discharge, in addition to causing environmental pollution, it also loses a certain chemical value