Method for preparing basic chromium sulfate from chromium plating sludge

A technology of chromium sulfate and sludge, which is applied in the field of waste resource utilization, can solve the problems of complicated process, increased recycling cost, and high chromium content in sludge, and achieves the effects of simple process flow, good economic benefits, and broad application prospects

Inactive Publication Date: 2018-06-22
HEBEI IRON AND STEEL
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Problems solved by technology

[0005] However, the high-temperature roasting method has the following problems: the recovery rate of chromium is low, the chromium content of the treated sludge is still high, and the energy consumption of high-temperature roasting is high, which increases the recovery cost, making this method difficult to be popularized
Although this method improves the recovery rate of chromium, its process is complex, there are many steps, and zinc powder needs to be added in the process of processing, which increases the production cost and does not utilize the popularization method.
[0007] In summary, the existing methods generally have problems such as complicated process, low element utilization rate, high energy consumption, and poor economic benefits, and it is difficult to realize the comprehensive application of chromium metal elements in chrome-plating sludge

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  • Method for preparing basic chromium sulfate from chromium plating sludge

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Effect test

Embodiment 1

[0035] A kind of method utilizing chrome-plating sludge to prepare basic chromium sulfate, described method comprises the steps:

[0036] (1) According to the solid-to-liquid ratio of 1:6, the chromium-plating sludge is mixed with a sulfuric acid solution with a concentration of 10wt%, heated to 90° C. for leaching for 1 hour under stirring conditions, and filtered after the reaction is completed to obtain tailings and chromium-containing leachate;

[0037] (2) Under the condition of stirring, the pH of the chromium-containing leaching solution obtained by using sodium hydroxide solution to adjust step (1) is 3, and the liquid after filtering to obtain basic chromium sulfate and crystallization; Return to step (1) for the leaching of chrome-plating sludge.

[0038] After testing, the leaching rate of chromium is 92%, and the mass fraction of dichromium trioxide in basic chromium sulfate is 22.3%.

Embodiment 2

[0040] A kind of method utilizing chrome-plating sludge to prepare basic chromium sulfate, described method comprises the steps:

[0041] (1) According to the solid-to-liquid ratio of 1:4, the chrome-plated sludge is mixed with a sulfuric acid solution with a concentration of 30wt%, heated to 95° C. for leaching for 2 hours under stirring conditions, and filtered after the reaction is completed to obtain tailings and chromium-containing leachate;

[0042] (2) Under the condition of stirring, the pH of the chromium-containing leaching solution obtained by using sodium hydroxide solution to adjust step (1) is 3.5, and the liquid after filtering to obtain basic chromium sulfate and crystallization; Return to step (1) for the leaching of chrome-plating sludge.

[0043] After testing, the leaching rate of chromium is 95%, and the mass fraction of dichromium trioxide in the basic chromium sulfate is 20.6%.

Embodiment 3

[0045] A kind of method utilizing chrome-plating sludge to prepare basic chromium sulfate, described method comprises the steps:

[0046] (1) According to the solid-to-liquid ratio of 1:3, mix the chromium-plating sludge with a sulfuric acid solution with a concentration of 25wt%, heat it to 85°C for 1.5h under stirring conditions, filter after the reaction is completed, and obtain tailings and chromium-containing leachate ;

[0047] (2) Under the condition of stirring, the pH of the chromium-containing leaching solution obtained by using sodium hydroxide solution to adjust step (1) is 2.8, and the liquid after filtering to obtain basic chromium sulfate and crystallization; Return to step (1) for the leaching of chrome-plating sludge.

[0048] After testing, the leaching rate of chromium is 92.5%, and the mass fraction of dichromium trioxide in the basic chromium sulfate is 25%.

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Abstract

The invention relates to a method for preparing basic chromium sulfate from chromium plating sludge. The method is characterized in that the chromium plating sludge and a sulfuric acid solution are mixed; heating is performed for leaching; after the leaching is completed, solid-liquid separation is performed to obtain chromium-containing leaching liquid and tailings; the pH of the obtained chromium-containing leaching liquid is regulated; the solid-liquid separation is performed to obtain basic chromium sulfate and crystallized liquid. The sulfuric acid solution is used for performing leachingtreatment on the chromium plating sludge, so that the chromium leaching rate is greater than 90 percent; through subsequent operation, the basic chromium sulfate product is obtained; the mass percentage of dichromium trioxide in the basic chromium sulfate is 20 to 25 percent; the resource reutilization of chromium elements in the chromium plating sludge is realized. The technological process is simple; the energy consumption is low; no waste water is discharged out in the whole production process; good economic benefits and wide application prospects are realized.

Description

technical field [0001] The invention relates to the technical field of waste resource utilization, in particular to a method for preparing basic chromium sulfate from chrome-plating sludge. Background technique [0002] Chromium is a strategic metal and ranks first. According to statistics, 76% of the world's chromium ore consumption is used in the metallurgical industry, but the global chromium resource reserves are not abundant, which is a scarce resource. Due to the gradual increase in demand in the chromium industry in recent years, it is urgent to realize the efficient comprehensive utilization of chromium ore and seek alternative raw materials for chromium, and some industrial wastes containing chromium should also be recycled and used in the preparation of chromium-related products. [0003] With the continuous expansion of the production capacity of cold-rolled automobile sheets, the discharge of cold-rolled chromium-containing wastewater in the steel industry has a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G37/08
CPCC01G37/08
Inventor 周冰晶李兰杰党征田京雷刘金哲
Owner HEBEI IRON AND STEEL
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