Resource utilization method of stainless steel pickling waste water crystallized salt sludge

A technology of pickling wastewater and crystallized salt, applied in the field of comprehensive utilization of resources, to achieve the effects of low production cost, environmental friendliness, high-efficiency enrichment and recovery

Inactive Publication Date: 2020-02-14
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, there is no report on the enrichment and recovery of nickel, chromium and manganese in salt mud

Method used

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  • Resource utilization method of stainless steel pickling waste water crystallized salt sludge
  • Resource utilization method of stainless steel pickling waste water crystallized salt sludge
  • Resource utilization method of stainless steel pickling waste water crystallized salt sludge

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Embodiment 1: In this embodiment, the salt mud contains Fe 25.12%, Ni 0.50%, Cr 0.40%, Mn 2.31%, and free acid 8.65%;

[0027] The temperature selection of stage I cooling crystallization and stage II cooling crystallization in the method of cascade crystallization:

[0028] Add stainless steel pickling wastewater crystalline salt mud into water and heat to a temperature of 65°C to dissolve to obtain a ferrous sulfate crude solution, wherein the total iron ion concentration of the ferrous sulfate crude solution is 120g / L, and at a stirring speed of 50r / min, the The crude ferrous sulfate solution is subjected to stage I cooling crystallization to obtain the crude salt of ferrous sulfate crystallization stage I and the crystallization mother liquor of stage I, wherein the stage I cooling crystallization is to rapidly cool the crude ferrous sulfate solution from 65°C to 20~40°C and crystallize 10min,

[0029] After testing, the metal concentration in the stage I crystalli...

Embodiment 2

[0039] Embodiment 2: In this embodiment, the salt mud contains Fe 25.12%, Ni 0.11%, Cr 0.12%, Mn 0.51%, and free acid 5.24%;

[0040] A resource utilization method of crystalline salt mud from stainless steel pickling wastewater (see figure 1 ),Specific steps are as follows:

[0041] (1) Separation of impurity element iron and valuable metal nickel, chromium and manganese: add stainless steel pickling wastewater crystalline salt mud into water and heat to a temperature of 70°C to dissolve to obtain a crude solution of ferrous sulfate, with a stirring rate of 50r / min , the crude ferrous sulfate solution is subjected to I stage cooling crystallization to obtain the I stage ferrous sulfate crystalline coarse salt and the I stage crystallization mother liquor, and the I stage crystallization mother liquor is carried out II stage cooling crystallization to obtain the II stage ferrous sulfate crystal coarse salt and the II stage crystallization Mother liquor; wherein the concentrat...

Embodiment 3

[0045] Embodiment 3: In this embodiment, the salt mud contains Fe 12.24%, Ni 0.68%, Cr 0.59%, Mn 2.87%, and free acid 14.88%;

[0046] A resource utilization method of crystalline salt mud from stainless steel pickling wastewater (see figure 1 ),Specific steps are as follows:

[0047] (1) Separation of impurity element iron and valuable metal nickel, chromium and manganese: add stainless steel pickling wastewater crystalline salt mud into water and heat to a temperature of 55°C to dissolve to obtain a crude solution of ferrous sulfate, with a stirring rate of 100r / min , the crude ferrous sulfate solution is subjected to I stage cooling crystallization to obtain the I stage ferrous sulfate crystalline coarse salt and the I stage crystallization mother liquor, and the I stage crystallization mother liquor is carried out II stage cooling crystallization to obtain the II stage ferrous sulfate crystal coarse salt and the II stage crystallization Mother liquor; wherein the concentr...

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Abstract

The invention relates to a resource utilization method of stainless steel pickling waste water crystallized salt sludge, and belongs to the technical field of comprehensive utilization of resources. After the salt sludge is dissolved, efficient separation between iron and nickel, chromium and manganese is realized with a cascade salting-out crystallization method, and crystallization mother liquorwith lower iron concentration and higher nickel, chromium and manganese concentrations and ferrous sulfate crystallized coarse salt are obtained. By aiming at further realizing separation between iron and nickel, chromium and manganese, the crystallization mother liquor is subjected to evaporation-freezing crystallization treatment, nickel, chromium and manganese are enriched while the iron concentration of the liquor is further reduced, then nickel, chromium and manganese are recovered in a hydroxide precipitate form with a sodium carbonate neutralization method, and effective enrichment ofnickel, chromium and manganese is realized. The precipitate residues can be taken as raw materials for recovering nickel, chromium and manganese or are returned to a tempering furnace in a stainless steel production process for self-use. According to the method, enrichment and recovery of valuable metals such as nickel, chromium and manganese with low content in the salt sludge are realized, and meanwhile, resource utilization of iron as a main impurity element in the salt sludge is realized.

Description

technical field [0001] The invention relates to a resource utilization method of crystalline salt mud from stainless steel pickling wastewater, and belongs to the technical field of comprehensive utilization of resources. Background technique [0002] Pickling is an essential link in the production and processing of stainless steel. During the pickling process of stainless steel, the surface oxide scale is generally firstly pickled with sulfuric acid. As the pickling process progresses, the free acid in the pickling solution becomes less and less, and more and more metal sulfates are formed in the reaction. When the metal concentration in the pickling solution reaches 50-60g / L, the metal salt will crystallize out from the pickling solution, and the pickling tank must be cleaned or replaced. Therefore, pickling wastewater contains a large amount of Fe 2+ Ions and free acids, also contain a small amount of Cr 3+ 、Ni 2+ , Mn 2+ Plasma. This kind of acidic wastewater is on...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22B7/00C22B23/00C22B34/32C22B47/00C01D5/18
CPCC01D5/18C22B7/006C22B23/0461C22B34/32C22B47/00Y02P10/20
Inventor 李旻廷魏昶李兴彬邓志敢
Owner KUNMING UNIV OF SCI & TECH
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