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Method for directly preparing pigment grade chromium hemitrioxide green by using chromic hydroxide

A technology of chromium hydroxide and chromium oxide green, applied in the direction of chromium oxide/hydrate, fibrous filler, etc.

Inactive Publication Date: 2009-07-08
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to solve the problem of calcination of chromium hydroxide, and at the same time remove the basic impurities in chromium hydroxide during the calcination process, thereby preparing pigment-grade chromium oxide green with excellent performance

Method used

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  • Method for directly preparing pigment grade chromium hemitrioxide green by using chromic hydroxide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Add 0.5L1mol / L sulfuric acid solution to 1L0.5mol / L sodium dichromate solution to acidify, react with 1L1mol / L formaldehyde for 3 hours, control the stirring speed to 400r / min, slowly add NaOH during the reaction to adjust the pH value, the end point pH= 6. After precipitation, the liquid is separated by filtration and washed to remove part of the Na + , to ensure Na after the filter cake is dried + <2%.

[0019] Filter cake with 1% Al 2 o 3 , ZnO, Sb 2 o 3 、H 3 PO 4 The materials are ball milled and mixed in a ball mill, and the mixed material is put into a muffle furnace for activation sintering, the sintering temperature is 900°C, and the sintering time is 2h. After sintering, the material is washed, dried, and after drying, the material is classified to obtain pigment-grade chromium oxide green. The main performance indicators are shown in the following table.

Embodiment 2

[0021] Add sodium hydroxide to 1L of 0.25mol / L chromium sulfate solution, stir and heat to 100°C for 3.5h, the pH of the solution rises gradually, and the final pH is controlled to be 7.0. Slurry filtration, washing to remove part of Na + , to ensure Na after the filter cake is dried + <2%.

[0022] Filter cake with 2% BaO, Al 2 o 3 , ZnO, Sb 2 o 3 、H 3 PO 4 , SiO 2 The materials are ball milled and mixed in a ball mill, and the mixed material is put into a muffle furnace for activation sintering, the sintering temperature is 1000°C, and the sintering time is 1h. After sintering, the material is washed, dried, and after drying, the material is classified to obtain pigment-grade chromium oxide green. The main performance indicators are shown in the following table.

Embodiment 3

[0024] Add 30g NaOH to 1L 300g / L sodium chromate solution to form sodium chromate alkaline solution, add 100g sulfur for reduction, heat to 95°C, heat and stir until Cr in the solution 6++ , to ensure Na after the filter cake is dried + <2%.

[0025] Filter cake with 2.5% Al(OH) 3 、Ba(OH) 3 、TiO 2 、H 3 PO 4 , SiO 2 The materials are ball milled and mixed in a ball mill, and the mixed material is put into a muffle furnace for activation sintering, the sintering temperature is 1100°C, and the sintering time is 1h. After sintering, the material is washed, dried, and after drying, the material is classified to obtain pigment-grade chromium oxide green. The main performance indicators are shown in the following table.

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Abstract

The invention discloses a method for preparing pigment-grade chromium oxide green directly from chromic hydroxide. The method comprises the steps of grinding and mixing chromic hydroxide and a certain quantity of additives, activating and sintering a mixture for 0.5 to 3 hours at a temperature between 800 and 1,100 DEG C, washing, drying and grading the mixture so as to obtain the pigment-grade chromium oxide green, wherein the chromic hydroxide can be obtained from the prior industrial production and various types of waste (waste residue and wastewater), or can be obtained by a low-temperature hydrogen reduction method in a patent (application number: 200510089010.8), and the additives are silicon compounds, titanium compounds, boron compounds, phosphorus compounds, aluminum compounds, barium compounds, zinc compounds and other compounds, such as SiO2, K2SiO3, Na2SiO3, TiO2, K2TiO3, B2O3, H2BO3, H3PO4, P2O3, Al2O3, Al(OH)3, Al2(SO4)3, AlCl3, Al(NO3)3, BaO, Ba(OH)2, BaSO4, BaCl2, Ba(NO3)2, ZnO, ZnCl2, ZnSO4, Zn(NO)3, Sb2O3, NiO, Ni(OH)2, CoO, Co(OH)2 and other substances. After the chromic hydroxide is activated and sintered at a temperature between 700 and 1,300 DEG C in an air atmosphere, the alkali-metal content of obtained chromium oxide is less than 0.3 percent, and cannot influence the properties of the pigment-grade chromium oxide green.

Description

technical field [0001] The present invention relates to a kind of preparation method of inorganic metal oxide pigment, specifically the method for directly preparing pigment grade chromium oxide green by chromium hydroxide Background technique [0002] Pigment grade chromium oxide green is mainly used in coatings, inks, plastics, ceramics, enamel, colored cement and other fields. In addition, pigment-grade chromium oxide green has some special properties and uses, such as being able to reflect infrared rays similar to chlorophyll, and is used to prepare camouflage paint similar to green leaf clusters. The chromium oxide green product used as a pigment has high quality requirements and must have good pigment performance, including shade, tinting strength, hiding power, etc. [0003] The production of chromium oxide chrome green pigment mainly adopts the thermal decomposition method of ammonium sulfate-sodium red alum and the thermal decomposition method of chromic anhydride....

Claims

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Application Information

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IPC IPC(8): C01G37/02C09C1/34
Inventor 徐红彬李平张懿李佐虎尤海霞
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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