Method of producing dichromium trioxide using chromic acid thermal decomposition continuous method

A technology of chromium trioxide and thermal decomposition, applied in the direction of chromium trioxide, chromium oxide/hydrate, etc., can solve the problems of inability to realize continuous production, insufficient collection and treatment, high labor intensity of employees, etc., to achieve pure color, The effect of lowering cost and improving productivity

Inactive Publication Date: 2003-12-03
民乐县化工厂
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The reaction time of raw materials is long, generally 8-12 hours, and it is produced intermittently, the productivity of the equipment is low, and continuous production cannot be realized
The raw materials entering the roasting equipment a

Method used

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  • Method of producing dichromium trioxide using chromic acid thermal decomposition continuous method
  • Method of producing dichromium trioxide using chromic acid thermal decomposition continuous method

Examples

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Effect test

example 1

[0029] With chromic acid (containing Cr 2 o 3 ≥99.5) and thick dichromium trioxide, boric acid, under the control of microcomputer, mix uniformly, its material ratio is chromic acid: thick dichromium trioxide: boric acid=100: 3: 0.2 (weight); Quantitative input rotary kiln fuel At the injection end, liquefied gas is used as the roasting fuel, which is directly in contact with the material and burned in parallel. During the slow and uniform rotation of the rotary kiln, the material quickly enters the high-temperature zone for roasting. The temperature in the high-temperature zone is 1000°C; the reaction time is 40 minutes; After the violent thermal decomposition reaction, the chromic acid is converted into dichromium trioxide; the dichromium trioxide is kept warm in the rotary kiln for 80 minutes; then it comes out of the tail of the rotary kiln, and the temperature of the kiln tail is 420°C. After cooling and crushing, it becomes a qualified chromium trioxide product; after c...

example 2

[0031] With chromic acid (containing Cr 2 o 3 ≥99.5) and thick dichromium trioxide, boric acid, under the control of microcomputer, mix evenly, its material ratio is chromic acid: thick dichromium trioxide: boric acid=100: 4: 0.3 (weight); Quantitative input rotary kiln fuel At the injection end, liquefied gas is used as the roasting fuel, which is directly in contact with the material and burned in parallel. During the slow and uniform rotation of the rotary kiln, the material quickly enters the high-temperature zone for roasting. The temperature in the high-temperature zone is 1050°C; the reaction time is 45 minutes; After the violent thermal decomposition reaction, the chromic acid is transformed into dichromium trioxide; the dichromium trioxide is kept warm in the rotary kiln for 90 minutes; then it comes out of the tail of the rotary kiln, and the temperature of the kiln tail is 435°C. After cooling and crushing, it becomes a qualified chromium trioxide product; after co...

example 3

[0033] With chromic acid (containing Cr 2 o 3 ≥99.5) and thick dichromium trioxide, boric acid, under the control of microcomputer, mix evenly, its material ratio is chromic acid: thick dichromium trioxide: boric acid=100: 5: 0.4 (weight); Quantitative input rotary kiln fuel At the injection end, liquefied gas is used as the roasting fuel, which is directly in contact with the material and burned in parallel. During the slow and uniform rotation of the rotary kiln, the material quickly enters the high-temperature zone for roasting. The temperature in the high-temperature zone is 1100°C; the reaction time is 52 minutes; After the violent thermal decomposition reaction, the chromic acid is transformed into dichromium trioxide; the dichromium trioxide is kept warm in the rotary kiln for 105 minutes; then it comes out from the tail of the rotary kiln with a temperature of 442°C. After cooling and crushing, it becomes a qualified chromium trioxide product; after cooling, the ungro...

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Abstract

A process for preparing Cr2O3 by continuous thermodecomposition of chromic acid includes such steps as proportionally mixing chromic acid, coarse Cr2O3 as returning charge and additive chosen from boric acid (preferable), ammonium chloride, starch and saw dust; after uniformly mixing under a computer control, parallel-flow combustion of the said mixture and liquefied gas as fuel in an insulated rotary furnace, thermodecomposition reaction to generate Cr2O3, keeping the temp. for a certain time, cooling and pulverizing to obtain the product. The unpulverized material is used as the said returning charge.

Description

(1) Technical field: [0001] The invention relates to a method for producing chromium sesquioxide, in particular to a method for producing chromium sesquioxide by a continuous method of thermal decomposition of chromic acid. (two) background technology: [0002] Chromium trioxide is also called chromium oxide, and chromium oxide specially used for pigments is also called chromium oxide green, which is a green powder. The main uses of chromium oxide are divided into four categories: making metal chromium and advanced (non-ferrous) chromium alloys; used as refractory materials; pigments (colorants); abrasives (abrasives). Metallurgical grade chromium oxide has strict restrictions on impurities C, S, Fe, As, Pb, etc.; refractory grade chromium oxide has regulations on melting point, density, impurities Fe, Si, etc.; pigment grade chromium oxide requires good pigment properties (color light , coloring power, oil absorption, hiding power, specific surface area, etc.); chromium ox...

Claims

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Application Information

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IPC IPC(8): C01G37/033
Inventor 韩登仑张忠元杨海
Owner 民乐县化工厂
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