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Green recycling method for steel pickling waste liquor

A technology of iron and steel pickling waste liquid and pickling waste liquid, which is applied in the direction of iron oxide/hydroxide, iron halide, chlorine/hydrogen chloride, etc., which can solve the problem of high hazard, large consumption of chemicals, high cost of chemicals and solid waste treatment and other issues to achieve the effects of reducing emissions, improving utilization, and saving resources

Active Publication Date: 2018-08-28
江苏宝钢精密钢丝有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Neutralizing the pickling waste with alkali (such as lime and liquid caustic soda) not only consumes a large amount of chemicals and produces a large amount of unusable solid waste, but also produces saline wastewater that is difficult to treat, and direct discharge is harmful to the water environment and soil bigger
At the same time, due to the high cost of chemicals and solid waste treatment, the overall cost of alkaline neutralization to treat pickling waste is very high

Method used

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  • Green recycling method for steel pickling waste liquor

Examples

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Effect test

Embodiment 1

[0030] A cutting steel wire pickling workshop in Jiangsu produces about 160 tons of pickling waste liquid every day, including 10 tons of waste pickling liquid and 150 tons of flushing waste water. The hydrochloric acid concentration in the waste pickling liquid is 12.8%, and the total iron concentration is 78.7 g / L; the hydrochloric acid concentration in the flushing wastewater is 0.35%, and the total iron concentration is 1.87g / L.

[0031] Adopt the method among the present invention to utilize above-mentioned pickling waste liquid, the steps are as follows:

[0032] 1) Use liquid caustic soda (30wt%) to neutralize and rinse the wastewater, and adjust the pH value to above 8.5. The ferrous hydroxide precipitate produced by the reaction is separated by settling in a sedimentation tank, and then filtered with a diaphragm filter press to obtain low-concentration brine And filter cake; filter cake contains ferrous hydroxide, ferrous hydroxide and about 50% water, low concentrati...

Embodiment 2

[0042] A steel pipe pickling workshop in Jiangsu produces about 130 tons of pickling waste liquid every day, including 15 tons of waste pickling liquid and 115 tons of flushing waste water. The concentration of hydrochloric acid in the waste pickling liquid is 2.51%, and the concentration of total iron is 191.8 g / L; the concentration of hydrochloric acid in the flushing wastewater is 0.07%, and the concentration of total iron is 4.3 g / L.

[0043] Adopt the method among the present invention to utilize above-mentioned pickling waste liquid, the steps are as follows:

[0044] 1) Use liquid caustic soda (30wt%) to neutralize and rinse the wastewater, and adjust the pH value to above 8.5. The ferrous hydroxide precipitate produced by the reaction is separated by settling in a sedimentation tank, and then filtered with a diaphragm filter press to obtain low-concentration brine And filter cake; filter cake contains ferrous hydroxide, ferrous hydroxide and about 50% water, low concen...

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Abstract

The invention discloses a green recycling method for steel pickling waste liquor. The green recycling method is characterized by specially comprising the following steps: neutralizing low-concentration pickling waste liquor with inorganic base, thereby obtaining ferric hydroxide or ferrous hydroxide precipitates and low-concentration saline water; performing acid and iron separation on high-concentration pickling waste liquor, thereby obtaining recycled acid and a ferric acid containing solution; dehydrating ferric hydroxide or ferrous hydroxide precipitates, and then, adding the ferric acid containing solution to obtain high-concentration iron salt solution; concentrating the low-concentration saline water to obtain concentrated saline water and recyclable water; electrolyzing concentrated saline water to prepare chlorine gas and an inorganic base solution; circulating the inorganic base solution for neutralizing pickling waste liquor; leading chlorine gas into the recycling acid to improve concentration of hydrochloric acid, and recycling concentrated recycled acid to a pickling line; and leading chlorine gas into a high-concentration iron salt solution to prepare a flocculatingagent. The green recycling method has the advantages that: a utilization rate of the pickling waste liquor is expected to be greatly increased, emission of three wastes of gas, liquid and solid is avoided throughout the process, and the method is economical, green and environmentally friendly.

Description

technical field [0001] The invention relates to the technical field of environmental protection, in particular to a green resource utilization method for iron and steel pickling waste liquid. Background technique [0002] Iron and steel pickling waste liquid is mainly composed of inorganic strong acid, iron salt and water, which is highly acidic and corrosive. If it is discharged directly without treatment, it will not only cause waste of resources, but also cause serious harm to the environment. At present, hydrochloric acid is the most used for pickling steel, so the components of most pickling waste liquids include hydrochloric acid, ferrous chloride and water, and may also contain a small amount of ferric chloride. In addition to waste pickling liquid, pickling waste liquid also includes other forms such as flushing liquid, towing liquid, dilution liquid, etc. Therefore, there are great differences in the composition and concentration of different pickling waste liquids,...

Claims

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Application Information

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IPC IPC(8): C01G49/02C01D3/04C01B7/01C01G49/10C23G1/36C25B1/46
CPCC01B7/012C01D3/04C01G49/02C01G49/10C23G1/36C25B1/46
Inventor 闵学刚徐正超方峰李琦刘阳骆凯翔李龙崔世云
Owner 江苏宝钢精密钢丝有限公司
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