Impurity removal and quality improvement of kaolinite clay

Kaolinite clay, as an important non-metallic mineral, is widely used in the industrial field due to its unique physical and chemical properties. However, the mineral impurities such as quartz, feldspar, mica, iron and titanium contained in the raw ore of kaolinite clay limit its use in high-end applications. In order to improve its industrial application value, these harmful impurities must be removed through the mineral processing process.

The mineral processing process mainly includes steps such as sand removal, iron removal and sulfur removal to ensure the purity of kaolinite clay. In industrial production, dry or wet purification can be used according to the characteristics and final use of kaolinite clay. Dry purification is usually used to produce hard kaolin, while wet purification is suitable for the production of soft kaolin.

Ore washing and sand removal is the first step of mineral processing. By adding dispersants to water, mineral particles are dissociated, and surface impurities are removed by mechanical auxiliary equipment such as drum washers or spiral sand washers. The washing process further ensures the full dispersion of the raw ore, water and dispersants, providing a pulp of appropriate fineness for subsequent process steps.

The classification process uses the difference in mineral particle size or density for separation, and often uses hydrocyclones, spiral classifiers or vibrating screens to remove coarse sand. Gravity separation uses density differences to remove coarse quartz and impurity minerals. The magnetic separation process removes iron-titanium minerals through a strong magnetic separator, while the flotation process adds reagents to adsorb fine impurity minerals onto the carrier to achieve impurity separation and whitening of kaolinite clay.

In the kaolin processing plant, the raw materials are evenly fed into the belt conveyor through a feeder, and are processed by spiral washers, abrasive washers, rotary screens, wheel washers and other equipment to achieve kaolin cleaning and classification. The dewatering screen and hydrocyclone group work together to separate the concentrate from the waste residue, and dehydrate it through a filter press to finally obtain a dry kaolin product.

Dry purification is suitable for high-quality mining areas with high montmorillonite content, especially in water-scarce areas such as Xinjiang, which shows its unique research significance. Wet purification is more suitable for bentonite with low quality. The grade of bentonite can be improved through natural sedimentation, centrifugation, flocculation and other methods.

The choice of purification process depends on the application requirements and added value of bentonite products. For example, edible and medicinal montmorillonite can choose chemical purification process to ensure that the montmorillonite content reaches more than 99% due to its high added value. In practical applications, the combined use of multiple purification methods can reduce production costs and improve product quality.