Comprehensive processing method for closed calcium carbide furnace gas and chromium slag

A calcium carbide furnace gas and comprehensive treatment technology is applied in the fields of comprehensive utilization of waste and environmental pollution control, which can solve the problems of high cost, secondary pollution, toxic and harmful gases, etc. Effect

Inactive Publication Date: 2015-12-09
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Dry detoxification: chromium slag and coal slag are mixed and calcined, and CO reduces hexavalent chromium to trivalent chromium. In order to prevent trivalent chromium from being oxidized by oxygen and turning yellow again, the detoxified chromium slag needs to be landfilled, occupying land, and there are two The risk of sub-pollution
The principle of wet detoxification of chromium slag is to transfer the hexavalent chromium in the chromium slag to the water phase, and then use a reducing agent to reduce the hexavalent chromium to non-toxic trivalent chromium to achieve the detoxification effect of chromium slag, but it needs to consume a lot of acid. High cost
[0005] In view of the above-mentioned problems currently existing, it is hoped that a new method of detoxifying chromium slag by using waste to treat waste can be found, and there are both reducing gases and toxic and harmful gases in calcium carbide furnace gas

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] The raw material calcium carbide furnace gas comes from a calcium carbide production enterprise in Qujing, Yunnan, with carbon monoxide 80~90%, hydrogen 2~8%, methane 2~3%, hydrogen sulfide 0.5~1%, phosphine 1~3%, hydrogen cyanide 1~ 3%.

[0017] (1) Dry and crush the chromium slag containing 2% sodium chromate by dry weight to 120 mesh, and set aside;

[0018] (2) Preheat the chromium-containing waste residue obtained in step (1) to 350°C, and then press 0.3m 3 The flow rate of / min is fed into the calcium carbide furnace gas after alkali washing (containing CO concentration greater than 80%, and the total content of trace gas impurities such as sulfur, phosphorus, and arsenic is controlled at 1%). After 50 minutes at 300 ° C, the flame is turned off to stop combustion and Continue to feed the reducing gas carbon dioxide; after cooling to 200°C, stop the ventilation to complete the detoxification of chromium slag, and the gas after combustion can be directly discharge...

Embodiment 2

[0021] The raw material calcium carbide furnace gas comes from a chemical enterprise in Panzhihua, Sichuan, with 80~85% carbon monoxide, 2~4% hydrogen, 1~3% methane, 1~2% hydrogen sulfide, 1~2% phosphine, and 1~1.5% hydrogen cyanide. %.

[0022] (1) Dry and crush the chromium slag containing 1% sodium chromate by dry weight to 250 mesh, and set aside;

[0023] (2) Preheat the chromium-containing waste slag obtained in step (1) to 750°C, and feed it into the calcium carbide furnace gas tail gas after alkali washing (containing CO concentration greater than 80%, and the total content of sulfur, phosphorus, arsenic and other trace gas impurities is controlled After 10 minutes at 1% at 750°C, turn off the flame to stop combustion and continue to pass in reducing gas nitrogen; after cooling to 150°C, stop ventilation to complete the detoxification of chromium slag, and the gas after combustion can be discharged directly.

[0024] The reduced slag after cooling was taken for inspec...

Embodiment 3

[0026] The raw material calcium carbide furnace gas comes from a chemical enterprise in Hefei, Anhui, with 85-90% carbon monoxide, 2-5% hydrogen, 1-3% methane, 0.5-1.5% hydrogen sulfide, 1-2% phosphine, and 1-2% hydrogen cyanide. %.

[0027] (1) Dry and crush the chromium slag containing 3% sodium chromate by dry weight to 800 mesh, and set aside;

[0028] (2) Preheat the chromium-containing waste slag obtained in step (1) to 500°C, and feed it into the calcium carbide furnace gas tail gas after alkali washing (containing CO concentration greater than 85%, and the total content of sulfur, phosphorus, arsenic and other trace gas impurities is controlled (0.5%) at 500°C for 30 minutes, turn off the flame to stop the combustion and continue to feed the reducing gas carbon monoxide; after cooling to 100°C, stop the ventilation to complete the detoxification of chromium slag, and the gas after combustion can be discharged directly.

[0029] The reduced slag after cooling was taken...

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PUM

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Abstract

The invention discloses a comprehensive processing method for closed calcium carbide furnace gas and chromium slag, and belongs to the technical field of comprehensive waste utilization and environment pollution improvements. According to the method, closed calcium carbide furnace gas and chromium slag make contact and are combusted, hexavalent chromium in the chromium slag is converted into trivalent chromium, and toxicity of the chromium slag is lowered. By means of the method, poisonous and harmful gas such as phosphorus hydride, hydrogen sulfide and cyanide in the calcium carbide furnace gas can be removed, the aim of emission is achieved in a combustion manner, and the hexavalent chromium in the chromium slag is reduced into the trivalent chromium while waste gas is purified. By means of the method, the dual effects of chromium slag detoxifying and calcium carbide furnace gas toxicity lowering can be achieved at the same time, the aim of treating waste through waste and the aim of comprehensive utilization are achieved, and the comprehensive processing method belongs to industry clean production and a novel pollution treatment process technology.

Description

technical field [0001] The invention relates to a method for comprehensively treating airtight calcium carbide furnace gas and chromium slag, and belongs to the technical field of waste comprehensive utilization and environmental pollution control. Background technique [0002] my country has become the country with the largest production and consumption of calcium carbide in the world. Hundreds of millions of calcium carbide furnace gas are emitted every year, the main components are carbon monoxide, nitrogen and hydrogen, the content is between 85-95%, and it also contains a large amount of dust, carbon dioxide, hydrogen sulfide, arsine, hydrogen fluoride, hydrogen cyanide, etc. Gas impurities, so the direct discharge of the gas will cause serious pollution to the environment. After purification, one-carbon chemical products, such as formic acid and methanol, can be produced. However, due to the immature purification technology at present, the product cost is unacceptable....

Claims

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Application Information

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IPC IPC(8): F23G7/00
Inventor 李彬宁平张英杰董鹏王学谦何力为
Owner KUNMING UNIV OF SCI & TECH
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