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Recycling harmless treatment method of stainless steel pickling waste water

A technology for the harmless treatment and pickling of wastewater, which is applied in the fields of metallurgical wastewater treatment, water/sewage treatment, chemical instruments and methods, etc. The effect of high burial cost, small footprint and high recovery purity

Active Publication Date: 2012-09-12
NANJING UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The purpose of the present invention is to overcome the problems in the prior art that the acid cannot be recycled and the nickel and chromium cannot be efficiently and completely separated during the treatment of stainless steel pickling wastewater, and a method for recycling and harmless stainless steel pickling wastewater is provided. The characteristics of pickling wastewater, combined with the requirements of pollutant discharge standards, make the wastewater acid and metal ions be recycled as resources, and at the same time realize the harmless treatment of the generated sediment, and realize the combination of economic benefits, environmental benefits and social benefits. Unite

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Examples

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Embodiment 1

[0045] The stainless steel pickling wastewater to be treated in this example was taken from a stainless steel pickling factory in Dainan, Jiangsu, and the water quality components are shown in Table 2 below.

[0046] Table 2 Water quality of stainless steel pickling wastewater in Example 1

[0047] project HNO 3 HF Fe 3+ Ni 2+ Cr 3+ f - (excluding HF) Concentration (g / L) 176.4 38.2 31.5 6.7 5.8 34.2

[0048] A kind of resource harmless treatment method of stainless steel pickling wastewater in this embodiment, its technological process is as follows figure 1 As shown, the stainless steel pickling wastewater is retarded by anion exchange resin, and then the goethite method is used to remove impurities, and then the neutralization precipitation method is further used to recover nickel. The specific steps are:

[0049] 1) Acid separation and recovery of nitric acid and hydrofluoric acid: pump the stainless steel pickling wastewater in ...

Embodiment 2

[0066] The water quality and basic steps of the wastewater treated in this example are the same as in Example 1, the difference is that in step (1), the acid concentration of the effluent is monitored by the conductivity, and when the conductivity suddenly rises to 40mS / cm, the liquid intake is stopped, and the obtained When the pH of the metal ion recovery solution is > 1.5, the recovery rate of metal ions drops to 75.3%. During the resin regeneration process, clean water is used to elute inorganic acids such as nitric acid and hydrofluoric acid adsorbed in the resin column from top to bottom. When the conductivity of the effluent drops to At 160mS / cm, stop regeneration; in step (2), the metal ion solution reacts in a three-necked flask at 80°C, neutralizes the acid generated by the reaction with 5% sodium carbonate and adjusts the end point pH to 5.0, and the nickel loss rate increases to 10.35%, but with the nickel recovered by washing, the total recovery rate is 99.3%, and ...

Embodiment 3

[0068] The water quality and basic steps of the waste water treated in this embodiment are the same as those in Example 1, the difference being that step (2) uses 10% sodium carbonate to adjust the end point pH to 3.5, and the loss rate of nickel is reduced to 8.5%. Nickel, the total recovery rate is 99.1%, the residual concentration of chromium rises to 85mg / L, and 28.05g of calcium chloride is added after 10 minutes of reaction (the dosage of calcium chloride is 110% of the theoretical amount of calcium required for the removal of fluoride ions ) to remove fluoride, and the concentration of fluoride ion after the reaction is 6.5mg / L. In step (4), the impurity-removing sediment was washed twice with water, and 2.01g (the weight of lime powder is 6% of the dry residue weight) of lime powder was added for stabilization. The leaching toxicity of the stabilized sediment met the requirements of GB 5085.3-2007. Requirements, for harmless sediment.

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Abstract

The invention discloses a recycling harmless treatment method of stainless steel pickling waste water, belonging to the toxic and harmful industrial waste water treatment field. The method comprises the following steps of: 1) recycling inorganic acids by an acid separation method: pumping stainless steel pickling waste water in which suspended matters are removed through filtering into a resin column so that the inorganic acids are absorbed on the resin; 2) removing impurities by a goethite method: pumping heavy metal ion solution into a reaction kettle, adjusting pH to a range from 3.5 to 5.0, and continuing reacting for 30-90 min, thereby removing iron, chromium and fluorine in the heavy metal ion solution in the form of dregs; 3) recycling nickel by a neutralized sedimentation method: feeding an alkaline liquor to nickel solution to adjust pH to a range from 9.5 to 12.5, and filtering and washing the filter residues, thereby obtaining nickelous hydroxide; and 4) performing harmlesstreatment on the dregs: after washing the dregs, adding lime powder to the dregs to realize stabilization treatment of harmful elements. The method is simple in operation and convenient for management; the high-concentration inorganic acids and nickel and the like contained in the waste water are all recycled, and simultaneously the generated dregs are harmlessly treated; and therefore the integration of economic benefit,environmental benefit and social benefit is realized.

Description

technical field [0001] The invention relates to the technical field of resourceful and harmless treatment of metal surface treatment wastewater, and more specifically, relates to a method for resourceful and harmless treatment of stainless steel pickling wastewater. Background technique [0002] Stainless steel not only has excellent mechanical, chemical and technological properties, but also has a beautiful appearance, high strength and light weight, and is widely used in petroleum, chemical, machinery, construction and other industries. In recent years, with the rapid growth of stainless steel consumption, my country's stainless steel output has grown rapidly, ranking first in the world since 2006, and reaching 11.6 million tons in 2009. At present, the main bottleneck factor restricting the upgrading, development and continuous growth of the stainless steel industry is the pickling wastewater generated during its production process. The pickling wastewater has high acidit...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/08C02F1/42C02F1/62C02F1/64C02F1/66C02F11/00B09B3/00C02F101/20C02F101/22C02F103/16
Inventor 刘福强杨才杰吴秋原孙晓文侯鹏凌晨李爱民
Owner NANJING UNIV
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