Washing method for obtaining low-sulfur hydrated chromic oxide

A hydrated chromium oxide and washing method technology, which is applied in the direction of chromium trioxide, chromium oxide/hydrate, etc., can solve the problems of not meeting the requirements of chemical enterprises and the quality requirements of low-sulfur hydrated chromium oxide, so as to save consumption and reduce Safety and environmental protection risks, the effect of reducing production costs

Active Publication Date: 2017-02-01
SICHUAN YINHE CHEM +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the existing hydrated chromium oxide washing process not only cannot meet the quality requirements for the preparation of low-sulfur hydrated chromium oxide, but also does not meet the requirements of modern new green, safe, environmentally friendly and sustainable chemical enterprises.

Method used

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  • Washing method for obtaining low-sulfur hydrated chromic oxide

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Embodiment 1

[0026] A washing method for obtaining low-sulfur hydrated chromium oxide, characterized in that it comprises the following steps:

[0027] Step 1, 2000kg and 2.0m of hydrated chromium oxide prepared by hydrothermal reduction of sodium chromate or sodium dichromate 3 Add water into the beating storage tank, raise the temperature to 82°C, beat at a constant temperature for 30 minutes, separate the beating liquid through a vacuum belt filter, and use pure water as the online washing water of the filter, and wash it through the filter on-line countercurrent for 3 stages until the washing liquid Medium Cr 6+ The content is up to 0ppm, and the filtrate I is 5.2m 3 and hydrated chromium oxide I;

[0028] Step 2: Add water to the obtained hydrated chromium oxide I for beating, then add a carbonic acid solution with a pH of 3.6 at room temperature, stir for 15 minutes, acidify the beating solution to a pH of 6.7, heat up to 81°C with steam as a heat source, and keep warm for 35 minut...

Embodiment 2

[0031] A washing method for obtaining low-sulfur hydrated chromium oxide, characterized in that it comprises the following steps:

[0032] Step 1, 2000kg of hydrated chromium oxide prepared by hydrothermal reduction of sodium chromate or sodium dichromate and 2.5m 3 Add water into the beating storage tank, raise the temperature to 85°C, beat at a constant temperature for 40 minutes, separate the beating liquid through a vacuum belt filter, and use pure water as the online washing water of the filter, and wash it through the filter on-line countercurrent for 3 stages until the washing liquid Medium Cr 6+ The content is up to 0ppm, and the filtrate I is 5.6m 3 and hydrated chromium oxide I;

[0033] Step 2: Add water to the obtained hydrated chromium oxide I for beating, then add a carbonic acid solution with a pH of 3 at room temperature, stir for 15 minutes, acidify the beating solution to a pH of 6.2, heat up to 83°C with steam as a heat source, and keep warm for 45 minutes...

Embodiment 3

[0036] A washing method for obtaining low-sulfur hydrated chromium oxide, characterized in that it comprises the following steps:

[0037] Step 1, 1500kg of hydrated chromium oxide prepared by hydrothermal reduction of sodium chromate or sodium dichromate and 1.5m 3 Add water into the beating storage tank, raise the temperature to 80°C, beat at a constant temperature for 30 minutes, separate the beating liquid through a vacuum belt filter, and use pure water as the online washing water of the filter, and wash it through the filter on-line countercurrent for 3 stages until the washing liquid Medium Cr 6+ content up to 0ppm, to obtain filtrate I and hydrated chromium oxide I;

[0038] Step 2. Add water to the obtained chromium oxide hydrate I for beating, then add a carbonic acid solution with a pH of 3 at room temperature, stir for 15 minutes, acidify the beating solution to a pH of 7, heat up to 80°C with steam as a heat source, and keep warm for 60 minutes , to obtain the h...

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Abstract

The invention discloses a washing method for obtaining low-sulfur hydrated chromic oxide. The washing method includes the steps that (1) hydrated chromic oxide prepared from sodium chromate or sodium dichromate in a hydrothermal-reduction mode is pulped and then separated through a filtering machine, countercurrent washing is carried out, and first filtered liquid and first hydrated chromic oxide are obtained; (2) the first hydrated chromic oxide is pulped, a carbonic acid solution is added at the room temperature, the mixture is stirred, the pulped liquid is acidized, the temperature is increased and then kept, and hydrated-chromic-oxide neutralized slurry liquid is obtained; (3) the hydrated-chromic-oxide neutralized slurry liquid is separated through a filtering machine, countercurrent washing is carried out, and second filtered liquid and second hydrated chromic oxide are obtained. According to the washing method, the series of problems that when the hydrated chromic oxide is washed, inorganic acid or organic acid serves as an acidifying agent, low-sulfur hydrated chromic oxide cannot be obtained, the production cost is high, and safety and environmental protection risks exist are solved; by means of the washing method for obtaining the low-sulfur hydrated chromic oxide, the low-sulfur hydrated chromic oxide can be obtained, the using amount of washing water is effectively saved, the washing efficiency of the hydrated chromic oxide is improved, and the production cost is reduced.

Description

technical field [0001] The invention relates to a method for obtaining hydrated chromium oxide, in particular to a washing method for obtaining low-sulfur hydrated chromium oxide. Background technique [0002] Chromium oxide green is one of the main products produced by the chromium salt industry. It has excellent chemical properties and thermal stability, and is widely used in many important economic fields, such as pigments, organic synthesis catalysts, grinding materials, fine ceramics, metallurgy and refractory materials, etc. each field. Chromium oxide green has strict requirements on sulfur content, and the sulfur content is less than 100ppm. Thermal decomposition of hydrated chromium oxide is the main preparation method to obtain various chromium oxide green products. In industry, hydrated chromium oxide is prepared by reaction of trivalent chromium salt with ammonia water and sulfur reduction of sodium chromate or sodium dichromate by precipitation method. Trivale...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G37/033
CPCC01G37/033
Inventor 周中田陈宁董明甫王方兵黄先东张良
Owner SICHUAN YINHE CHEM
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