Unlock instant, AI-driven research and patent intelligence for your innovation.

A continuous pressurized self-heating liquid-phase decomposition method of chromite oxide

A liquid phase oxidation, chromite technology, applied in the direction of chromate/dichromate, can solve the problems of high equipment investment and high pressure in the reaction process, and achieve low energy consumption, short process flow, and significant economic benefits. Effect

Active Publication Date: 2019-09-27
INST OF PROCESS ENG CHINESE ACAD OF SCI
View PDF7 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method is beneficial to the high-efficiency separation of sodium chromate, but the pressure of the reaction process is relatively high, and the investment in equipment is relatively high.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • A continuous pressurized self-heating liquid-phase decomposition method of chromite oxide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] According to NaOH / chromite=3:1, mix 70wt% lye and chromite evenly, heat the mixture to 290°C and transport it to a continuous pressurized reactor. Add potassium permanganate according to the pro-oxidant: chromite = 0.005:1, pass through ozone to react, the partial pressure is 0.8MPa, and the gas flow rate is 4.2m 3 / h. The heat preservation of the reactor makes the reaction in the kettle continue by relying on self-heating, and at the same time controls the balance of the amount of feed and output. After the reaction is completed, it enters the flash evaporator, and the high-temperature steam after the flash returns to the chromite ore and lye mixing preheating process, the slurry is added with formaldehyde and separated from the solid and liquid, the filtrate returns to mix with the chromite, and the sodium chromate crystal slag (chromium sodium hydroxide 35wt%, sodium hydroxide 55wt%) for washing and crystallization. Components of the sodium chromate solution after ...

Embodiment 2

[0026] According to NaOH / chromite=8:1, 35wt% lye and chromite were mixed evenly, and the mixture was heated to 220°C and transported to a continuous pressurized reactor. According to the pro-oxidant: chromite = 0.01:1, add sodium permanganate, feed the mixture of oxygen and air to react, the partial pressure is 1.8MPa, and the gas flow rate is 0.8m 3 / h. The heat preservation of the reactor makes the reaction in the kettle continue by relying on self-heating, and at the same time controls the balance of the amount of feed and output. After the reaction is completed, enter the flash evaporator, and the high-temperature steam after the flash returns to the mixed preheating process of chromite ore and lye, the slurry is added butanol and carried out solid-liquid separation, and the filtrate returns to mix with chromite, and the solid (sodium chromate 15wt %, sodium hydroxide 35wt%) for washing and crystallization. Components of the sodium chromate solution after crystallization...

Embodiment 3

[0028] According to NaOH / chromite=6:1, mix 55wt% lye and chromite evenly, heat the mixture to 250°C and transport it to a continuous pressurized reactor. According to the pro-oxidant: chromite = 0.2:1, add sodium manganate, feed oxygen to react, the partial pressure is 1.3MPa, and the gas flow rate is 3.2m 3 / h. The heat preservation of the reactor makes the reaction in the kettle continue by relying on self-heating, and at the same time controls the balance of the amount of feed and output. After the reaction finishes, enter the flash evaporator, and the high-temperature steam after the flash returns to the mixed preheating process of chromite ore and lye, the slurry adds valeraldehyde and carries out solid-liquid separation, and the filtrate returns to mix with chromite, and the solid (sodium chromate 25wt %, sodium hydroxide 45wt%) for washing and crystallization. Components of sodium chromate solution after crystallization: sodium hydroxide 4wt%, sodium chromate 15wt%. ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a continuous pressing self-heating type decomposition method of liquid-phase chromium oxide iron ores. The decomposition method comprises the following steps: taking chromite as a raw material, taking a sodium hydroxide solution as a reaction medium, mixing and preheating slurry, then conveying the mixed and preheated slurry into a continuous pressing reaction kettle, introducing an oxidizing gas, controlling the balance of the feeding amount and the discharging amount, preserving heat in the reaction kettle to enable continuous reaction in the kettle, and after the reaction is completed, carrying out solid-liquid separation, washing, crystal dissolving, impurity removal and the like to obtain a sodium chromate solution. The method is simple in process, short in flow, high in operability and easy in realization of industrial production, and chromium-containing wastewater is not produced in the process disclosed by the invention. The alkali liquor in the system can be recycled, and the method is environmentally friendly and free of pollution.

Description

technical field [0001] The invention relates to the field of chromium salt production, in particular to a continuous pressurized self-heating liquid-phase oxidized chromite decomposition method. Background technique [0002] my country's chromium salt production has accounted for 40% of the world. The overall scale of my country's chromium salt factories has increased, and the production capacity has also generally increased (small factories with less than 10,000 t / a have been eliminated, and there are 2 large factories with more than 50,000 t / a). The resource utilization rate of the existing calcium-containing roasting process of chromite is very low, and each ton of product will produce 2.5 to 3 tons of Cr6+-containing carcinogenic waste residue and other chromium-containing waste. The calcium-free roasting process effectively reduces the pollution of chromium slag discharge, but the production of each ton of products still produces 0.8 tons of chromium-containing waste r...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): C01G37/14
Inventor 曲景奎魏广叶余志辉齐涛
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI