What Is The Application of Barite in The Coatings Industry


Barite is a sulphate mineral of strontium. Its main component is BaSO4. It is characterized by high density, chemical stability, non-magneticity and toxicity. It is widely used in petroleum, chemical, light industry, metallurgy, medicine, agriculture and atomic energy, military. And other fields.

barite.jpg


As a body pigment, barite powder is widely used in the field of paints and coatings, and plays an important role in improving the thickness, abrasion resistance, water resistance, heat resistance, surface hardness and impact resistance of coating films.

(1) In the latex paint, the fine barite powder may have a function of a translucent white pigment due to the high refractive index of the barite, and replaces part of the titanium white powder.

(2) In the chemical resistant coating, the barite powder is inert, insoluble in water, acid, alkali and organic mediation, which can increase the surface hardness of the topcoat and improve the color stability.

(3) In powder coatings, barite powder can improve its gloss, fluidity, filling and compatibility with various pigments.


1. Ultrafine pulverization and surface modification of barite powder

The barite powder product used in paint coatings is not only high in purity but also fine in particle size. Therefore, in addition to beneficiation and purification, ultrafine grinding and surface modification are required.

(1) Superfine grinding
The barite has a low Mohs hardness and is dense, brittle, and easy to pulverize. Therefore, the ultrafine pulverization of barite is mostly carried out by a dry process. The commonly used equipments are ultrafine grinding mill, jet mill, mechanical impact mill, vibrating mill, etc., wherein the barite can be crushed to D97 ≤ 5 μm by a ultrafine grinding mill. If the ultra-fine pulverization process is followed by the wet beneficiation and purification, the wet superfine pulverization process may also be employed, and the equipment may be a stirring mill, a vibration mill, a ball mill or the like.

Barite chemical purification and ultrafine pulverization process.jpg

Barite Grinding Equipment:

1. 0-3mm Hammer Mill;
2. 50-325 mesh YGM Raymond Mill;
3. 200-3000 mesh HGM Ultra Fine Mill;
4. 325-3000 mesh CLUM Vertical Roller Mill (2µm>50% ).

 

(2) Surface modification
Due to the hydrophilic nature of the barite powder surface, its application in organic systems is limited. The purpose of surface modification is to modify its dispersibility in organic systems, prevent precipitation of agglomerates when used in paints, and increase the gloss, toughness, adhesion, etc. of the paint film.
There are various methods for surface modification of barite powder, such as surface chemical coating, precipitation reaction coating, surface chemistry and mechanical chemistry. Various surface modifiers such as surfactants, coupling agents, and inorganic oxides can be selected according to different application fields.
The experimental results show that the barite powder modified by a surface modifier containing COOH, OH and SO3 functional groups has high activation index, good dispersibility and fluidity, and has good application effect and can satisfy red alkyd. Requirement requirements for blending paints.

Barite Powder Modification Machine,Barite Powder Surface Coating Machine

2, barite powder quality index requirements
In the paint industry, barite powder requires sufficient fineness and high whiteness.

Application
Require Index
Remarks
BaSO4(%)
SiO2(%)
Fe2O3(%)
Through Size(mesh)
Painting
90~95
——
0.05
<325
High whiteness is required
Rubber filler
>98
<0.36
trace
<325
Containing Mn, Cu, Pb impurities is not allowed
Ordinary glass
>96
<0.1
<0.2
60
SiO2<1.5%,Al2O3<0.15%
Lithopone
95~98
——
<1
——
SiO2<1.5%,Al2O3 the less the better

 barite powder application areas and indicators requirements

3. Application prospects

Coatings are an important downstream application for non-metallic minerals, and China is the world's largest paint producer. In 2017, coating production reached 20.41 million tons. With the rapid development of the coatings industry, the demand for barite powder is increasing, the quality requirements are becoming more and more strict and diversified, and the market products tend to be functional and refined.

Although China is a big country with heavy barite reserves and a large country of production, the industry's technology has not kept up with the increasing proportion of the industry's output in the world. Therefore, China's barite powder industry should increase investment in technology and talents for high-end products, improve the quality of production operations, strengthen the research and development of high-end products (such as fine bismuth chemical products), and cultivate deep processing technology (purification, ultrafine, modified And compound talents can accelerate the transformation and upgrading of the industry and maximize the economic benefits of high-quality resources. 

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