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Method of preparing chromium oxide powder using water heat reducing chromate

A chromate and chromium oxide technology, applied in the directions of chromium trioxide, chromium oxide/hydrate, etc., can solve the problems of high cost, environmental pollution, product quality, complicated process, etc., and achieves simple composition, low production cost, and technological process. simple effect

Inactive Publication Date: 2007-07-18
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the invention is to overcome existing Cr 2 o 3 Due to the defects of high cost, complex process, environmental pollution and low product quality in production, it is possible to provide a method for preparing by hydrothermal direct reduction of chromate with simple process flow, low production cost, no pollutant discharge, and suitable for large-scale industrial production. Chromium Oxide Ultrafine Powder Method

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  • Method of preparing chromium oxide powder using water heat reducing chromate
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Embodiment 1

[0030] 200gK 2 CrO 4 Dissolved in 800gH 2 In O, a concentration of 20 wt% K was obtained 2 CrO 4 Aqueous solution, get 85ml37wt% formaldehyde solution in addition, the consumption of formaldehyde (according to stoichiometric ratio) is 140mol% of potassium chromate in the mixed solution, and above-mentioned K 2 CrO 4 The solution is placed together in a hot-pressed reactor, and then 0.8 g of sodium dodecylsulfonate is added, mixed evenly, and the reactor is sealed and then introduced into CO 2 Gas 0.8MPa, at 600r·min -1 Raise the temperature to 160°C under high-speed stirring, stop heating after 3 hours of reaction, and open the kettle to take out the material after the temperature is lowered to below 50°C, and the hydrated Cr obtained above 2 o 3 The slurry was centrifuged at 8000rpm, the solid phase was dried at 100°C for 10 hours, then placed in a muffle furnace, calcined at 500°C for 2 hours, the calcined product was washed with water and centrifuged three times, the...

Embodiment 2

[0032] 200gK 2 CrO 4 Dissolved in 800gH 2 In O, a concentration of 20 wt% K was obtained 2 CrO 4 Aqueous solution, get 85ml37wt% formaldehyde solution in addition, the consumption of formaldehyde (according to stoichiometric ratio) is 140mol% of potassium chromate in the mixed solution, and above-mentioned K 2 CrO 4 Put the solution together in a hot-pressed reaction kettle, then add 0.8g of sodium dodecylsulfonate, mix evenly, and pass in CO after airtight 2 Gas 0.8MPa, at 600r·min -1 Raise the temperature to 160°C under high-speed stirring, stop heating after 3 hours of reaction, and open the kettle to take out the material after the temperature is lowered to below 50°C, and the hydrated Cr obtained above 2 o 3 The slurry is centrifuged at 8000rpm, the solid phase is dried at 100°C for 10 hours, then placed in a muffle furnace, calcined at 700°C for 2 hours, the calcined product is washed with water and centrifuged three times, then dried to obtain Cr 2 o 3 The prod...

Embodiment 3

[0034] 200gK 2 CrO 4 Dissolved in 800gH 2 In O, a concentration of 20 wt% K was obtained 2 CrO 4 Aqueous solution, get 85ml37wt% formaldehyde solution in addition, the consumption of formaldehyde (according to stoichiometric ratio) is 140mol% of potassium chromate in the mixed solution, and above-mentioned K 2 CrO 4 Put the solution together in a hot-pressed reaction kettle, then add 0.8g of sodium dodecylsulfonate, mix evenly, and pass in CO after airtight 2 Gas 0.8MPa, at 600r·min -1 Raise the temperature to 160°C under high-speed stirring, stop heating after 3 hours of reaction, and open the kettle to take out the material after the temperature is lowered to below 50°C, and the hydrated Cr obtained above 2 o 3 The slurry is centrifuged at 8000rpm, the solid phase is dried at 120°C for 8 hours, then placed in a muffle furnace, calcined at 1000°C for 2 hours, the calcined product is washed with water and centrifuged three times, then dried to obtain Cr 2 o 3 The prod...

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Abstract

This invention relates to a preparation method that prepares chromic oxide powder by using water heat to deoxidize chromate. Use chromate water solution as raw material, CO2 as acidifying agent, process by surface active agent, directly deoxidize at condition of heat water, get hydrated Cr2O3 slurry, centrifugalize, separate, dry, calcinate hydrated Cr2O3 at different temperature, prepare globular Cr2O3 micropowder. Its grade size is between submicron and nanometer. This invention utilizes surface active agent to control sexavalent chromic salt which can be directly deoxidized to get trivalence chrome crystal. It can control hydrated chromic oxide calcinating temperature to prepare globular Cr2O3 micropowder of which grade size can be controlled.

Description

technical field [0001] The invention belongs to the technical field of preparation of functional inorganic materials, and in particular relates to a method for preparing chromium oxide powder by using hydrothermal reduction of chromate. Background technique [0002] Chromium oxide (Cr 2 o 3 ) is an important inorganic green pigment, metallurgical raw material, grinding material and catalyst, widely used in fine ceramics, anti-corrosion coatings, wave-absorbing materials, green polishing paste, organic catalytic synthesis and other fields. Cr is currently produced industrially 2 o 3 The methods mainly include chromic anhydride pyrolysis method and hexavalent chromium salt reduction method. The pyrolysis method of chromic anhydride is to use sodium dichromate to acidify with concentrated sulfuric acid to produce chromic anhydride, and then roast it at high temperature to make Cr 2 o 3 , high cost and serious pollution; the hexavalent chromium salt reduction method genera...

Claims

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Application Information

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IPC IPC(8): C01G37/033
Inventor 张鹏曹宏斌郑诗礼徐红彬张懿
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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