阅读说明：本技术 一种含铬危险废弃物处理方法 (Chromium-containing hazardous waste treatment method ) 是由 林森 于 2020-12-25 设计创作，主要内容包括：本发明公开了一种含铬危险废弃物处理方法,涉及危险废弃物处理领域,包括以下步骤：水洗；去除水分得到滤渣A；在滤渣A中加入盐酸和水搅拌均匀得到混合物B；将混合物B去除水分,水洗至滤渣呈中性,得到滤渣C；在滤渣C中加入氢氟酸和水,得到混合物D；将混合物D去除水分,水洗至滤渣呈中性,得到滤渣E；将滤渣E烘干；粉碎成颗粒状；焙烧得到三氧化二铬粗产品；将三氧化二铬粗产品再次粉碎并使用强碱溶液洗涤,晒干或烘干,得到三氧化二铬细产品；将三氧化二铬细产品进行研磨和筛分,得到三氧化二铬粉末产品。本发明能够解决现有的含铬污泥处理具有严重的二次污染隐患和造成铬资源浪费的问题。(The invention discloses a method for treating chromium-containing hazardous waste, which relates to the field of hazardous waste treatment and comprises the following steps: washing with water; removing water to obtain filter residue A; adding hydrochloric acid and water into the filter residue A, and uniformly stirring to obtain a mixture B; removing water from the mixture B, and washing with water until the filter residue is neutral to obtain filter residue C; adding hydrofluoric acid and water into the filter residue C to obtain a mixture D; removing water from the mixture D, and washing with water until the filter residue is neutral to obtain filter residue E; drying the filter residue E; pulverizing into granules; roasting to obtain a crude product of chromium sesquioxide; crushing the coarse chromium sesquioxide product again, washing the coarse chromium sesquioxide product by using a strong base solution, and drying in the sun or by baking to obtain a fine chromium sesquioxide product; and grinding and screening the fine chromium sesquioxide product to obtain a chromium sesquioxide powder product. The invention can solve the problems of serious secondary pollution hidden trouble and chromium resource waste of the existing chromium-containing sludge treatment.)

1. The method for treating the chromium-containing hazardous waste is characterized by comprising the following steps of:

washing the chromium-containing sludge with water to remove impurities in the chromium-containing sludge;

removing water from the chromium-containing sludge washed by the water in the step (1) by using a filter press to obtain filter residue A;

adding hydrochloric acid and water into the filter residue A, and uniformly stirring to obtain a mixture B;

removing water from the mixture B by using a filter press, and washing the mixture B with water for multiple times until the filter residue is neutral to obtain filter residue C;

adding hydrofluoric acid and water into the filter residue C, and uniformly stirring to obtain a mixture D;

removing water from the mixture D by using a filter press, and washing the mixture D with water for multiple times until filter residue is neutral to obtain filter residue E;

drying or baking the filter residue E in the sun;

crushing the filter residue E which is dried in the sun or in the oven into particles;

roasting the crushed granular filter residue E to obtain a chromium sesquioxide crude product;

crushing the coarse chromium sesquioxide product again, washing the coarse chromium sesquioxide product by using a strong base solution, and drying in the sun or by baking to obtain a fine chromium sesquioxide product;

and grinding and screening the fine chromium sesquioxide product to obtain a chromium sesquioxide powder product.

2. The method for treating chromium-containing hazardous waste according to claim 1, wherein the filter presses used in step (2), step (4) and step (6) are plate and frame filter presses.

3. The method of claim 1, wherein the stirring time in the step (3) is 0.8-0.9 h.

4. The method of claim 1, wherein the stirring time in the step (5) is 0.4 to 0.6 hours.

5. The method as claimed in claim 1, wherein in step (7), residue E is treated at 210-^oAnd C, drying for 1.5-2.5 h.

6. The method as claimed in claim 1, wherein the step (10) is performed at 210-230 ℃ with the crude chromium oxide product washed with the strong alkaline solution^oAnd C, drying for 1.5-2.5 h.

7. The method of claim 1, wherein the strong alkaline solution used in the step (10) is sodium hydroxide solution.

8. The method of claim 1, wherein in the step (11), the ground fine chromium oxide product is sieved by using a vibrating sieve.

Technical Field

The invention relates to the field of hazardous waste treatment, in particular to a method for treating chromium-containing hazardous waste.

Background

The treatment of chromium-containing wastewater by a sewage treatment plant can generate chromium-containing sludge, the chromium-containing sludge contains a large amount of chromium hydroxide and other forms of trivalent chromium compounds, the chromium-containing sludge is a dangerous waste which needs to be treated by a chemical method or a physical method, and otherwise, secondary pollution can be generated.

At present, the treatment of the chromium-containing sludge is generally landfill or incineration, however, the two treatment modes can not eliminate or reduce the hidden trouble of secondary pollution of the chromium-containing sludge.

China is a country with chromium resources lacking, and the chromium in the sludge cannot be recycled by the existing chromium-containing sludge treatment mode, so that the chromium resources are seriously wasted.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for treating chromium-containing hazardous waste, and solves the problems of serious secondary pollution hidden trouble and chromium resource waste in the conventional chromium-containing sludge treatment.

The technical scheme adopted by the invention for solving the technical problems is as follows: a method for treating chromium-containing hazardous waste comprises the following steps:

(1) washing the chromium-containing sludge with water to remove impurities in the chromium-containing sludge;

(2) removing water from the chromium-containing sludge washed by the water in the step (1) by using a filter press to obtain filter residue A;

(3) adding hydrochloric acid and water into the filter residue A, and uniformly stirring to obtain a mixture B;

(4) removing water from the mixture B by using a filter press, and washing the mixture B with water for multiple times until the filter residue is neutral to obtain filter residue C;

(5) adding hydrofluoric acid and water into the filter residue C, and uniformly stirring to obtain a mixture D;

(6) removing water from the mixture D by using a filter press, and washing the mixture D with water for multiple times until filter residue is neutral to obtain filter residue E;

(7) drying or baking the filter residue E in the sun;

(8) crushing the filter residue E which is dried in the sun or in the oven into particles;

(9) roasting the crushed granular filter residue E to obtain a chromium sesquioxide crude product;

(10) crushing the coarse chromium sesquioxide product again, washing the coarse chromium sesquioxide product by using a strong base solution, and drying in the sun or by baking to obtain a fine chromium sesquioxide product;

(11) and grinding and screening the fine chromium sesquioxide product to obtain a chromium sesquioxide powder product.

Further, the filter presses used in the step (2), the step (4) and the step (6) are all plate and frame filter presses.

Further, the stirring time in the step (3) is 0.8-0.9 h.

Further, the stirring time in the step (5) is 0.4-0.6 h.

Further, in the step (7), the filter residue E is processed at step 210-230^oAnd C, drying for 1.5-2.5 h.

Further, in the step (10), the crude product of chromium oxide washed by strong alkali solution is processed at 210-^oAnd C, drying for 1.5-2.5 h.

Further, in the step (10), the alkali solution used is a sodium hydroxide solution.

Further, in the step (11), the ground fine chromium oxide product is sieved by using a vibrating sieve.

The invention has the following beneficial effects:

the method for treating the chromium-containing hazardous waste can convert chromium hydroxide and trivalent chromium compounds in other forms in the chromium-containing sludge into chromium sesquioxide powder products, and removes impurities such as calcium, iron, magnesium, aluminum and the like and silt mixed in the chromium-containing sludge through hydrochloric acid and hydrofluoric acid in the conversion process, thereby ensuring that the purity of the chromium sesquioxide powder products is over 99.6 percent.

In the chromium-containing sludge treatment process, through repeated crushing, drying and roasting, the crushing can increase the surface area of the filter residue E or the chromium oxide crude product, so that the drying and roasting efficiency is higher, and the energy is greatly saved.

Detailed Description

Example 1:

a method for treating chromium-containing hazardous waste comprises the following steps:

(1) washing the chromium-containing sludge with water to remove impurities in the chromium-containing sludge;

(2) removing water from the chromium-containing sludge washed by the water in the step (1) by using a filter press to obtain filter residue A;

(3) adding hydrochloric acid and water into the filter residue A, and uniformly stirring to obtain a mixture B;

(4) removing water from the mixture B by using a filter press, and washing the mixture B with water for multiple times until the filter residue is neutral to obtain filter residue C;

(5) adding hydrofluoric acid and water into the filter residue C, and uniformly stirring to obtain a mixture D;

(6) removing water from the mixture D by using a filter press, and washing the mixture D with water for multiple times until filter residue is neutral to obtain filter residue E;

(7) drying or baking the filter residue E in the sun;

(8) crushing the filter residue E which is dried in the sun or in the oven into particles;

(9) roasting the crushed granular filter residue E to obtain a chromium sesquioxide crude product;

(10) crushing the coarse chromium sesquioxide product again, washing the coarse chromium sesquioxide product by using a strong base solution, and drying in the sun or by baking to obtain a fine chromium sesquioxide product;

(11) and grinding and screening the fine chromium sesquioxide product to obtain a chromium sesquioxide powder product.

The stirring time in the step (3) is 0.8 h.

The stirring time in the step (3) is 0.4 h.

In the step (7), filter residue E is treated at 210^oAnd C, drying for 1.5 h.

In the step (10), the crude product of the chromium oxide washed by the strong alkali solution is treated at 210^oAnd C, drying for 1.5 h.

In the step (10), the alkali solution is sodium hydroxide solution.

In the step (11), the ground fine chromium oxide product is screened by using a vibrating screen.

The method for treating the chromium-containing hazardous waste can convert chromium hydroxide and trivalent chromium compounds in other forms in the chromium-containing sludge into chromium sesquioxide powder products, and removes impurities such as calcium, iron, magnesium, aluminum and the like and silt mixed in the chromium-containing sludge through hydrochloric acid and hydrofluoric acid in the conversion process, thereby ensuring that the purity of the chromium sesquioxide powder products is over 99.6 percent.

In the chromium-containing sludge treatment process, through repeated crushing, drying and roasting, the crushing can increase the surface area of the filter residue E or the chromium oxide crude product, so that the drying and roasting efficiency is higher, and the energy is greatly saved.

Example 2:

a method for treating chromium-containing hazardous waste comprises the following steps:

(12) washing the chromium-containing sludge with water to remove impurities in the chromium-containing sludge;

(13) removing water from the chromium-containing sludge washed by the water in the step (1) by using a filter press to obtain filter residue A;

(14) adding hydrochloric acid and water into the filter residue A, and uniformly stirring to obtain a mixture B;

(15) removing water from the mixture B by using a filter press, and washing the mixture B with water for multiple times until the filter residue is neutral to obtain filter residue C;

(16) adding hydrofluoric acid and water into the filter residue C, and uniformly stirring to obtain a mixture D;

(17) removing water from the mixture D by using a filter press, and washing the mixture D with water for multiple times until filter residue is neutral to obtain filter residue E;

(18) drying or baking the filter residue E in the sun;

(19) crushing the filter residue E which is dried in the sun or in the oven into particles;

(20) roasting the crushed granular filter residue E to obtain a chromium sesquioxide crude product;

(21) crushing the coarse chromium sesquioxide product again, washing the coarse chromium sesquioxide product by using a strong base solution, and drying in the sun or by baking to obtain a fine chromium sesquioxide product;

(22) and grinding and screening the fine chromium sesquioxide product to obtain a chromium sesquioxide powder product.

The stirring time in the step (3) is 0.85 h.

The stirring time in the step (3) is 0.5 h.

In the step (7), the filter residue E is treated at 220^oAnd C, drying for 2 h.

In the step (10), the crude product of the chromium oxide washed by the strong alkali solution is treated at 220^oAnd C, drying for 2 h.

In the step (10), the alkali solution is sodium hydroxide solution.

In the step (11), the ground fine chromium oxide product is screened by using a vibrating screen.

Example 3:

a method for treating chromium-containing hazardous waste comprises the following steps:

(23) washing the chromium-containing sludge with water to remove impurities in the chromium-containing sludge;

(24) removing water from the chromium-containing sludge washed by the water in the step (1) by using a filter press to obtain filter residue A;

(25) adding hydrochloric acid and water into the filter residue A, and uniformly stirring to obtain a mixture B;

(26) removing water from the mixture B by using a filter press, and washing the mixture B with water for multiple times until the filter residue is neutral to obtain filter residue C;

(27) adding hydrofluoric acid and water into the filter residue C, and uniformly stirring to obtain a mixture D;

(28) removing water from the mixture D by using a filter press, and washing the mixture D with water for multiple times until filter residue is neutral to obtain filter residue E;

(29) drying or baking the filter residue E in the sun;

(30) crushing the filter residue E which is dried in the sun or in the oven into particles;

(31) roasting the crushed granular filter residue E to obtain a chromium sesquioxide crude product;

(32) crushing the coarse chromium sesquioxide product again, washing the coarse chromium sesquioxide product by using a strong base solution, and drying in the sun or by baking to obtain a fine chromium sesquioxide product;

(33) and grinding and screening the fine chromium sesquioxide product to obtain a chromium sesquioxide powder product.

The stirring time in the step (3) is 0.9 h.

The stirring time in the step (3) is 0.6 h.

In the step (7), filter residue E is added to 230^oAnd C, drying for 2.5 hours.

In the step (10), the crude product of the chromium oxide washed by the strong base solution is processed at 230^oAnd C, drying for 2.5 hours.

In the step (10), the alkali solution is sodium hydroxide solution.

In the step (11), the ground fine chromium oxide product is screened by using a vibrating screen.

The above description is only a preferred embodiment of the present invention, and not intended to limit the present invention in any way, and those skilled in the art can make various changes and modifications to the equivalent embodiments without departing from the scope of the present invention, and all such changes, modifications, equivalents and improvements that can be made to the above embodiments without departing from the technical spirit of the present invention are within the spirit and principle of the present invention.