Process for reduction detoxication of chromic slag by adopting dry method

A chromium slag and dry method technology, applied in the field of chromium slag dry reduction and detoxification technology, can solve the problems of high energy consumption and high cost in production, and achieve the effects of stable properties, low cost, simple and feasible process

CN102978376BInactive Publication Date: 2014-04-09WUHAN INSTITUTE OF TECHNOLOGY
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2014-04-09
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a process for reduction detoxication of chromic slag by adopting a dry method. The process is characterized by comprising the steps of: fully mixing chromic slag with pulverized coal, under the condition of a closed reduction atmosphere, uniformly feeding the obtained mixture into a reacting furnace through a feeder, reasonably regulating the atmosphere, dewatering, preheating, roasting and reducing, cooling, quenching, grinding, and magnetically separating to obtain iron concentrate and nontoxic chromic slag. The process is simple and easy to operate; the final products comprise high-grade iron concentrate and the nontoxic chromic slag; and the process is an effective way for harmlessly recycling the chromic slag.
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Description

technical field

[0001] The invention belongs to a method for treating and reusing toxic industrial waste residues, and in particular relates to a dry reduction and detoxification process of chromium residues. Background technique

[0002] The environmental pollution and waste of resources caused by solid waste is one of the important issues of environmental and resource protection in the world today. Common compounds of chromium include trivalent and hexavalent forms. Metal chromium and its alloys and trivalent chromium compounds are harmless to the human body. Trivalent chromium is one of the necessary trace elements in living organisms. An appropriate amount of trivalent chromium is beneficial to the human body and plants . The harm of hexavalent chromium to the human body is related to the water solubility of the compound. Soluble hexavalent chromium can cause mucous membrane inflammation, ulcers, and even nasal perforation; skin eczema and the formation of "chrome sores...

Examples

Embodiment 1

[0035] A dry reduction and detoxification process for chromium slag, fully mixing chromium slag (a chromium slag with a particle size of less than 1 mm in Qujing, Yunnan, with a CrⅥ content of 2.09% and a Fe content of 28.5%) with coal powder, and the particle size of the coal powder is less than 3 mm , the mass ratio of pulverized coal to chromium slag is 2:100. Under airtight conditions, the obtained mixture is evenly fed into the reaction furnace through a star feeder, and the following process is completed:

[0036] 1) Dehydration: The mixture is in the state of stirring, and the neutral or oxidizing atmosphere is controlled, and the temperature of the first layer is 200 ° C for 5.5 minutes of dehydration and drying;

[0037]2) Preheating: the dehydrated and dried mixture is in the state of stirring, at a temperature of 300 ℃ ~ 400 ℃, use preheating to reduce the exhaust gas, and pre-reduce for 11 minutes;

[0038] 3) Roasting: The preheated mixture is roasted in a reducin...

Embodiment 2

[0044] A dry reduction and detoxification process for chromium slag, fully mixing chromium slag (a chromium slag with a particle size of less than 0.5mm in Qujing, Yunnan, with a CrⅥ content of 1.78% and a Fe content of 32.5%) with coal powder, and the particle size of the coal powder is less than 3 mm, the mass percentage of pulverized coal accounts for 3% of the total amount of the two. Under airtight conditions, the resulting mixture is evenly fed into the reaction furnace through a screw feeder to complete the following process:

[0045] 1) Dehydration: The mixture is in the state of stirring, and the neutral or oxidative atmosphere is controlled, and the first layer is dehydrated and dried for 6 minutes at a temperature of 200 ° C ~ 300 ° C;

[0046] 2) Preheating: the dehydrated and dried mixture is in the state of stirring, and at a temperature of 350 ° C ~ 500 ° C, the waste gas is reduced by preheating for 12 minutes;

[0047] 3) Roasting: The preheated mixture is roa...

Embodiment 3

[0053] A dry reduction and detoxification process for chromium slag, fully mixing chromium slag (Hubei Huangshi Zhenhua Chemical Industry chromium slag with a particle size of less than 1mm, CrⅥ content of 1.68%, and Fe content of 12.5%) with coal powder, and the particle size of coal powder is less than 3 mm, and the mass percentage of pulverized coal accounts for 2.5% of the total amount of the two. Under airtight conditions, the obtained mixture is evenly fed into the reaction furnace through a screw feeder to complete the following process:

[0054] 1) Dehydration: The mixture is in the state of stirring, and the neutral or oxidative atmosphere is controlled, and the dehydration is carried out at 250°C for 5.0 minutes;

[0055] 2) Preheating: The dehydrated and dried mixture is in the state of stirring, at a temperature of 350 ℃ ~ 480 ℃, use preheating to reduce the exhaust gas, and pre-reduce for 10 minutes;

[0056] 3) Roasting: The preheated mixture is roasted in a redu...