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Detoxification method of chromium slag in production of sulfuric acid

A technology for sulfuric acid production and chromium slag, which is applied to chemical instruments and methods, sulfur compounds, solid waste removal, etc., can solve problems such as hexavalent chromium pollution, poor reduction conditions, and inability to completely restore hexavalent chromium, and achieve the goal of eliminating Effect of toxin

Inactive Publication Date: 2006-07-12
SICHUAN YINHE CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the technical defects of the above two methods, the reduction conditions are not good, and the reducing agent is insufficient, the hexavalent chromium cannot be completely reduced, and the reduced chromium slag is easy to turn yellow, causing the hexavalent chromium to be polluted

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] Embodiment 1: a kind of method for the detoxification of chromium slag in the production of sulfuric acid, chromium slag is pulverized to 80 orders, adds pyrite and mixes by chromium slag 10% (percentage by weight) ratio, enters roasting in the rotary kiln of φ 2.5m, Control the temperature in the furnace to be 600-800°C, and control the feeding rate to be 15 tons / hour. After testing, there is no hexavalent chromium and acid solution in the sulfuric acid slag, no hexavalent chromium in the wastewater, no hexavalent chromium in the sulfuric acid, and 0.5ppm of water-insoluble trivalent chromium in the sulfuric acid.

Embodiment 2

[0015] Embodiment 2: Crushing the chromium slag to 100 mesh, adding pyrite in the ratio of 20% (percentage by weight) of the chromium slag and mixing, entering into a φ3m rotary kiln for roasting, controlling the temperature in the furnace to be 800-1000°C, and controlling the feeding amount 25 tons / hour. After testing, there is no hexavalent chromium and acid solution in the sulfuric acid slag, no hexavalent chromium in the wastewater, no hexavalent chromium in the sulfuric acid, and 0.3ppm of water-insoluble trivalent chromium in the sulfuric acid.

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PUM

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Abstract

The invention relates to a detoxification method of chromic slag in the process of producing vitriol with rotary kiln. It mixes the chromic slag and ferro-sulphur ore as raw material and injects sulfur into the rotary kiln to be baked while the baking temperature is controlled between 500-1000Deg. C. In the baking process, the sulfur dioxide generated by ferro-sulphur ore can fully deoxidize the hexavalent chromium of chromic slag to remove the toxin (water soluble chromium and acid soluble chromium) in the chromic slag. The invention can realize detoxification of chromic slag without affecting the production and quality of vitriol, and the generated vitriol slag can be used as cement mixing material to avoid secondary pollution.

Description

Technical field: [0001] The invention is a method for detoxifying chromium slag in sulfuric acid production, in particular a method for detoxifying water-soluble hexavalent chromium and water-insoluble calcium chromate in chromium slag in sulfuric acid production using a rotary kiln. Background technique: [0002] Most of the present chromium salt production is roasted with calcareous fillers, such as limestone, dolomite, chromite, soda ash and some chromium slag mixed powder. Chromium slag 2-2.5 tons. Since the chromium residue contains hexavalent chromium, up to 2-3% (chromium trioxide juice), and the chromium residue contains water-insoluble calcium chromate, which is a carcinogen, so whether a large amount of chromium residue is discarded or utilized, If the toxins (water-soluble hexavalent chromium and water-insoluble calcium chromate) are not removed, it will cause great threat and damage to human beings and the environment. At present, there are two most commonly us...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09B3/00C01B17/74
Inventor 李先荣马顺友张国庆胡义华
Owner SICHUAN YINHE CHEM