Method for treating hexavalent chromium in solid wastes

A solid waste, hexavalent chromium technology, applied in the direction of the protection device against harmful chemicals, etc., can solve the problems of poor treatment effect, small treatment capacity, large consumption of acid and alkali, etc. Reagent consumption, mild reaction conditions, and avoidance of secondary pollution

Active Publication Date: 2019-04-05
宝武集团环境资源科技有限公司
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Problems solved by technology

[0005] The high-temperature reduction method (dry method) mainly uses reducing substances to reduce hexavalent chromium to trivalent chromium at high temperature, but there are problems such as high processing cost, small processing amount, and incomplete processing.
[0006] The wet reduction method (wet method) mainly focuses on the chemical treatment method, that is, the use of reducing substances in the liquid medium to convert hexavalent chromium into trivalent chromium and fix it, such as ferrous sulfate reduction method and sulfite reduction method , barium salt method, etc., and then developed the ferrite method, ion exchange method, electrolysis method, etc., but due to the poor treatment effect of these methods, it is difficult to meet the standards or due to high cost, economically unfeasible and other reasons, to a large extent limit its practical application
[0007] The solidification / stabilization method is to pulverize the solid waste containing hexavalent chromium, add a reducing stabilizer such as ferrous sulfate or inorganic acid according to a certain proportion after pulverization, reduce the hexavalent chromium to trivalent chromium, and then add an appropriate amount of solidification Such as cement, etc., add water and stir, solidify and condense, seal the chromium-containing compound in the solidified body substrate, it is difficult to dissolve again, and achieve the purpose of solidification stabilization and harmlessness, but this method needs to add a large amount of curing agent, causing increase problems such as capacity and cost increase
[0008] In addition, the conventional method for treating hexavalent chromium is to add a reducing agent under acidic conditions to reduce the highly toxic hexavalent chromium to less toxic trivalent chromium, and then add alkaline substances to form chromium hydroxide precipitates. However, this The method requires high treatment conditions, consumes a large amount of acid and alkali, and the dosage of reducing agent is far greater than the theoretical value, which is easy to cause waste of reducing agent and secondary pollution.

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  • Method for treating hexavalent chromium in solid wastes
  • Method for treating hexavalent chromium in solid wastes
  • Method for treating hexavalent chromium in solid wastes

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Example 1 Heavy metal stabilization treatment method for heavy metal dust in a waste incineration power plant along the coast

[0041] Take dust from a waste incineration power plant in the coastal area, divide it into 4 groups, each group is 100g, and add 4g of lime sulfur, SN9 heavy metal stabilizer, BES6180 heavy metal stabilizer and hydrogenated disulfide shown in formula I to the 4 groups of samples. Carboxylate heavy metal stabilizer, in formula I, R 1 is an alkyl group with less than 8 C atoms, R 2 for H, M for Na + , add 25g of water and stir evenly to make a fly ash solidified sample, and cure for 24 hours.

[0042] According to HJ / T300-2007, the leaching toxicity test was carried out on the cured sample after stabilization treatment, and the leaching toxicity results are shown in Table 1.

[0043] Table 1 The leaching toxicity of heavy metal dust stabilized in a coastal waste incineration power plant

[0044]

[0045]As can be seen from Table 1, the hea...

Embodiment 2

[0048] Embodiment 2 The heavy metal stabilization treatment method of industrial solid waste in North China

[0049] Take the northern industrial solid waste and divide it into 4 groups, each group of 100g, add 4g of lime sulfur, SN9 heavy metal stabilizer, BES6180 heavy metal stabilizer and hydrogenated dithiocarboxylate shown in formula I to the 4 groups of samples Heavy metal stabilizer, R in formula I 1 for H, R 2 is H or an alkyl group with less than 8 C atoms, and M is NH 4 + ; Add 25g of water and stir evenly to make a solidified fly ash sample, and cure for 24 hours at a curing temperature of 20-25°C.

[0050] According to HJ / T300-2007, the leaching toxicity test is carried out on the stabilized solid waste, and the leaching toxicity is detailed in Table 2.

[0051] Table 2 Leaching Toxicity of Heavy Metal Stabilization Treatment of Solid Waste in North Industries

[0052]

[0053] As can be seen from the data in table 2, adopt the industrial solid waste Cr and...

Embodiment 3

[0055] Example 3 Stabilization treatment method of waste incineration fly ash in a waste incineration power plant in Guangdong

[0056] In order to compare different additions of reducing agents on Cr and Cr 6+ The reduction effect of waste incineration fly ash from a waste incineration power plant in Guangdong was taken and divided into 12 groups, each group 100g.

[0057] Add different concentrations (mass fraction 1%, 2%, 3%, 4%) of sodium sulfide, FeSO 4 ·H 2 O and the hydrogenated dithiocarboxylate heavy metal stabilizer shown in formula I of the present invention, R 1 for H, R 2 for H, for M

[0058] K + , treatment for comparison, add 30g of water to make a solidified block, curing time 24 hours.

[0059] According to HJ / T300-2007, the leaching toxicity test of the stabilized solidified block is carried out, and the relevant leaching toxicity is shown in Table 3.

[0060] Table 3 Leaching toxicity of waste incineration fly ash stabilization treatment in a waste i...

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Abstract

A method for treating hexavalent chromium in solid wastes comprises the following steps: mixing a heavy metal stabilizer with pulverized or powdery solid wastes, adding water, stirring uniformly, standing and solidifying to form a solidified material, wherein the heavy metal stabilizer is a hydrodithiocarboxylate compound as shown in formula I; maintaining the formed solidified material for more than 1 day under natural conditions; and detecting leaching toxicity of the maintained solidified material. The hexavalent chromium is reduced into trivalent chromium under mild conditions, metal chelating is carried out to generate stable heavy metal chelate, a large number of acid and alkali do not need to be consumed additionally, the chemical feeding amount is small, resources and energy are saved, and secondary pollution is avoided; a solidifying and stabilizing effect can be achieved without additionally adding a solidifying agent, the cost is reduced, and capacity increasing is avoided;and the leaching toxicity Cr6+ of the stabilized solid wastes is lower than the national standard limit value, and thus, the method is suitable for being popularized and used.

Description

technical field [0001] The invention belongs to the technical field of solid waste treatment, and in particular relates to a method for treating hexavalent chromium in solid waste. Background technique [0002] With the development of economy and social progress, various environmental pollution problems have become prominent in people's daily life, especially heavy metal pollution, which has become the most serious problem in my country's environmental pollution control, and the pollution disposal demand of heavy metals in solid waste is particularly urgent. [0003] Heavy metal chromium mainly comes from chromium ore processing, electroplating, chemical industry, leather making, textile, printing and dyeing and other industries. Among them, hexavalent chromium has high water solubility and toxicity, and is considered to be a carcinogenic, teratogenic and mutagenic substance. It is not easy to be biodegraded and difficult to handle. It is a ubiquitous pollutant. [0004] At...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): A62D3/33
CPCA62D3/33
Inventor 季玉玄卢四平赵倩倩
Owner 宝武集团环境资源科技有限公司
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