Improved process for producing finely divided hematite and iron oxide red pigments

A hematite and finely crushed technology, applied in the field of red iron oxide pigments, can solve the problems that the reaction process is not very predictable, not very stable, and not in a stable manner, and achieves the effect of high reliability

Active Publication Date: 2017-03-01
LANXESS DEUTDCHLAND GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, under these reaction conditions the conversion of iron relative to the nitric acid used fluctuates, i.e. the process does not proceed in a steady manner
It was found that the quality of iron used under these conditions also had an effect on the conversion of iron relative to the nitric acid used making the course of the reaction less predictable and less stable from reaction to reaction

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0079] 8.44kg (151.1mol) of iron punching (metal) plate (iron punching sheet, iron punching sheet) (thickness 0.8mm) was placed in 61.3kg of water and heated to 80°C. 18.67 kg of 30 wt% nitric acid (88.9 mol) at a feed rate of 1851 g / min were added over a period of 10 min. The amount of nitric acid added corresponds to an initial calculated concentration of 7% by weight in the reaction mixture. The temperature of the reaction mixture increased to a maximum of 151° C. and the pressure increased and was limited to 4.3 bar within 20 minutes after the end of the nitric acid addition. A suspension of hematite was produced and 12.06 kg of finely divided hematite were thus obtained after filtration and drying of the residue. The hematite obtained in this way has a BET surface area of ​​48m according to DIN66131 2 / g. The molar conversion factor for metallic iron was 1.7 based on the nitric acid used.

Embodiment 2

[0081] 5.42 kg (97.1 mol) of iron wire pins (nails) were placed in 68.2 kg of water and heated to 80°C. 11.84 kg of 30.4 wt% nitric acid (57.1 mol) were fed at a feed rate of 1174 g / min over a period of 10 min. The amount of nitric acid added corresponds to an initial calculated concentration of 4.5% by weight in the reaction mixture. The temperature of the reaction mixture increased to a maximum of 125° C. and the pressure increased and was limited to 4.5 bar within 60 min after the end of the nitric acid addition. A suspension of hematite was produced and 6.54 kg of finely divided hematite were thus obtained after filtration and drying of the residue. The hematite obtained in this way has a BET surface area of ​​73m according to DIN66131 2 / g. The molar conversion factor for metallic iron was 1.43 based on the nitric acid used.

Embodiment 3

[0083] 8.44kg (151.1mol) of wire pins (nails) were placed in 61.3kg of water and heated to 95°C. 18.67 kg of 30 wt% nitric acid (88.9 mol) were added at a feed rate of 1851 g / min over a period of 10 min. The amount of nitric acid added corresponds to an initial calculated concentration of 7% by weight in the reaction mixture. The temperature of the reaction mixture rose to a maximum of 143[deg.] C. and the pressure increased and was limited to 3.4 bar within 30 minutes after the end of the nitric acid addition. A suspension of hematite was produced and 10.67 kg of finely divided hematite were thus obtained after filtration and drying of the residue. The hematite obtained in this way has a BET surface area of ​​51m according to DIN66131 2 / g. The molar conversion factor for metallic iron was 1.5 based on the nitric acid used.

[0084] Particle size: The finely divided hematite produced according to the present invention has a particle size less than or equal to 100 nm. 90%...

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Abstract

The present invention relates to an improved process for the production of finely divided haematite and of iron oxide red pigments made up of the finely divided haematite and the use of the finely divided haematites and iron oxide red pigments produced by this process.

Description

technical field [0001] The present invention relates to an improved method for producing finely divided haematite and iron oxide red pigment (iron oxide red) composed of finely divided hematite and finely divided hematite produced by this method And the use of iron oxide red pigment. Background technique [0002] Iron oxides are used in many industrial fields. Thus, they are used, for example, as color pigments for ceramics, building materials, plastics, surface coatings and paper, as base or carrier materials for various catalysts, and for adsorbing or absorbing pollutants. Magnetic iron oxides are used in magnetic memory media, toners, ferrofluids or in medical applications such as contrast agents for magnetic resonance tomography. [0003] In many of these applications, the particle size of the iron oxide particles plays a key role. Particles with a particle size of less than or equal to 100 nm are required for applications in which the technical effect is determined b...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01G49/06
CPCB82Y30/00C01G49/06C01P2004/64C01P2006/12C01P2006/80Y10T428/2982C09C1/24
Inventor 吉多·克特勒乌多·奥尔特曼于尔根·基施克维茨
Owner LANXESS DEUTDCHLAND GMBH
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