Method for treating iron-containing acidic wastewater

Abstract

The invention discloses a method for treating iron-containing acidic wastewater. The method comprises the following steps of: performing neutralization reaction on the iron-containing acidic wastewater and carbide slag slurry or lime milk in a neutralization tank by mechanical mixing; delivering neutralized slag-containing wastewater into a sedimentation tank; delivering wastewater supernatant in the sedimentation tank into a wastewater oxidation tank, adjusting a pH value in a pH value adjustment zone of the wastewater oxidation tank by using a small amount of the iron-containing acidic wastewater, and delivering the wastewater supernatant into an aeration zone for oxidization; delivering wastewater containing a small amount of ferric suspended substances into a clarification tank, and discharging clarified clean wastewater directly; and delivering sediment settled in the sedimentation tank in the step two and sediment settled in the clarification tank in the step four into a sediment oxidation tank by pumping, performing aeration oxidation treatment, delivering the sediment into a filter press for filtration, returning filtered water to the wastewater oxidation tank for treatment together with the wastewater supernatant from the sedimentation tank, and treating filtered residue by the conventional method. The clarified clean wastewater treated by the method has the pH value of 6 to 9 and the iron concentration of 2 mg/L, and meets the national discharge standard.

Description

technical field [0001] The invention belongs to a method for treating acidic iron-containing wastewater, in particular to a method for treating acidic iron-containing wastewater in sulfuric acid titanium dioxide production by using calcium carbide slag or lime as an alkali agent. Background technique [0002] The production of titanium dioxide by the sulfuric acid method will produce a large amount of acidic iron-containing wastewater, about 100 to 130 tons of acidic iron-containing wastewater (hereinafter referred to as titanium dioxide acidic wastewater) for each ton of titanium dioxide produced, and its sulfuric acid concentration is generally 1 to 3%. The iron concentration is generally 0.1 to 0.4% (mainly ferrous). The traditional treatment method of titanium dioxide acidic wastewater is to add a certain amount of calcium carbide slurry or lime milk into the acidic wastewater, and then neutralize and oxidize it through aeration. The wastewater treatment time is generall...

AI Technical Summary

Problems solved by technology

[0003] The main disadvantages of the traditional titanium dioxide acid wastewater treatment method are that the air bubbles produced by aeration hinder mass transfer, which reduces the neutralization reaction and ferrous oxidation speed; the carbon dioxide brought in by aeration reacts with calcium hydroxide to form scale, which makes the equipment volume Rapid shrinkage and poor treatment effect; the filtration of all wastewater requires a large filtration area, and the pH of the filtered water needs to be treated with commercial sulfuric acid to reach the standard, and the iron concentration is likely to exceed 5mg / L

In short, the traditional method of treating titanium dioxide acidic wastewater requires huge equipment and high energy consumption, and the treatment effect is unstable.

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