Treatment method for high-concentration arsenic waste water

Abstract

The invention discloses a treatment method for high-concentration arsenic waste water, and relates to the technical field of sewage treatment. The method comprises the following steps of: 1, carrying out pH neutralization adjustment, and executing solid-liquid separation after neutralization; 2, oxidizing sedimentation (I): treating the arsenic waste water with an alkaline coagulant, then, executing oxidization, and carrying out inclined plate settling to realize solid-liquid separation; 3, oxidizing sedimentation (II): adding lime or lime milk in the neutralized waste water, executing oxidization simultaneously, and carrying out inclined plate settling to realize solid-liquid separation; 4, ferric salt coagulation: adding an inorganic coagulant in water solution, stirring, and then, adding an organic flocculant; and 5, air floatation separation: adding a surface active agent, separating iron and arsenic slag, executing pressure filtration and drying, and carrying out oxidizing roasting. The method has the beneficial effect that the effluent As concentration of the treated waste water can meet the national emission standard; the As concentration of the leach liquor of the oxidized and roasted arsenic waste residue buried underground is far below the national stipulated limit, and arsenic is cured effectively.

Description

【Technical field】 [0001] The invention relates to a treatment technology for industrial arsenic-containing wastewater, in particular to a treatment method for high-concentration arsenic-containing wastewater. 【Background technique】 [0002] The high-sulfur flue gas produced in the non-ferrous smelting process can be used to make acid. The acid-making process will produce a large amount of dirty acid wastewater. This type of wastewater usually has high acid concentration, high turbidity, and contains arsenic, fluorine, lead, zinc, mercury, and copper. , cadmium and other harmful elements, especially the high arsenic content, sometimes even as high as 20g / L, far exceeding the national emission standard of 0.5mg / L; arsenic and its compounds are carcinogens with high toxicity, so if not It is very easy to cause pollution to the environment, and once the pollution is formed, it is difficult to eliminate, especially once the arsenic pollutes the water body and soil, it will enter ...

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Problems solved by technology

[0005] However, there are obvious deficiencies in the above-mentioned chemical precipitation methods. First, the lime precipitation method, the iron salt precipitation method, and the iron salt-lime co-precipitation method need to add a large amount of chemical agents, which are precipitated in the form of precipitates, resulting in a large amount of arsenic. Toxic waste residues have secondary pollution problems; second, the sulfidation precipitation method can only achieve the purpose of effectively removing arsenic under acidic conditions. In the acidic range, it is easy to produce toxic and irritating H2S gas, the working environment is very harsh, and the operating cost High, thus limiting its wide application in industry; Third, the degree of automation of the treatment process is low, easy to foul and block, and the operating cost is high

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