Treatment agent of wastewater rich in arsenic ions and heavy metal ions and preparation method

Abstract

The invention relates to a treatment agent of wastewater rich in arsenic ions and heavy metal ions and a preparation method. The agent is a polymeric ferric salt which is formed by mixing, by mass, 90-110 parts of polysilicate ferric chloride, 0.5-1.5 parts of sodium silicate, 3-8 parts of ferrous sulfate and 0.2-0.8 part of hydrogen peroxide and has a strong oxidizing property. The treatment agent is rich in hydroxyl free radical which is very high in oxidability, the agent itself has very high oxidability, As ions in wastewater can be effectively oxidized, the As ions are changed from trivalent arsenic to pentavalent arsenic which is easy to precipitate, and formed precipitate is more stable; the agent is rich in a large amount of trivalent arsenic and contains a large amount of silicic acid, silicic acid has a very good adsorption bridging function, the bridging and net capturing functions of ferric ions are greatly strengthened, flocculability is high, heavy metal can be effectively captured, the removal rate of arsenic is greatly increased, formed alumen ustum is big and dense, precipitation is rapid, and the precipitate is high in stability.

Description

technical field [0001] The invention relates to the technical field of wastewater treatment, in particular to a treatment agent and a preparation method for wastewater rich in arsenic ions and heavy metal ions. Background technique [0002] During the smelting and production process of copper, tin, lead and zinc, etc., a large amount of wastewater rich in arsenic ions and heavy metal ions is produced, and arsenic is a highly toxic carcinogen. 2g, the maximum lethal dose is 0.1 to 0.3. The laws and regulations on water environment protection in my country have strictly stipulated the discharge standard of arsenic, requiring domestic water, surface water and various industrial sewage and wastewater to meet the national sewage comprehensive discharge standard (GB8978 -1996) and Surface Water Environmental Quality Standards (GB3838-2002) for the control of arsenic, the discharge can only be carried out after reaching the standard, so it is very necessary to study which chemical ca...

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Problems solved by technology

[0004] 1. Smelter wastewater contains strong acidity. If polyferric sulfate is used to remove arsenic ions in wastewater by sedimentation, it is necessary to add a large amount of lime milk to neutralize the acidity, which results in the final effluent Ca 2+ The content is relatively high (about 600-1000mg / L), the total dissolved solids (salts) are also high, and the amount of sludge is very large;

[0005] 2. The treatment process using traditional polyferric sulfate or ferrous sulfate is lengthy, the operation management is complicated, and the cost is relatively high, and the treated water can only be discharged up to the standard, but cannot meet the water quality standard of reused water;

[0006] 3. Generally, to achieve arsenic compliance, two stages (two sedimentation tanks) must be set up, and iron salts should be added to the second stage to achieve arsenic compliance, which is costly

[0007] 4. Precipitation forms waste residue rich in trivalent arsenic, which has a poor stable phase and cannot be used, which affects the environment. If it accumulates for a long time, it is easy to cause secondary pollution

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