Ultrafine Talcum Powder Production Process
Ultra-fine talc powder is an ultra-fine natural talc powder processed from high-purity talc ore. It is widely used in plastics, rubber, coatings and other industries. Ultrafine talc powder is mainly used in PU transparent primer and PU solid color topcoat in solvent-based wood coatings. It is widely used in industrial coatings, mainly to reduce costs and improve the filling performance of primers. In water-based latex paint, it can endow the paint with good brushability, leveling, gloss retention and flexibility, and at the same time effectively improve the corrosion resistance and dryness of the coating.
Talc beneficiation can be divided into flotation, hand separation, magnetic separation, photoelectric separation. At present, there are still some defects in flotation technology, so the whole industry basically does not use flotation beneficiation; manual selection is based on the difference in smoothness of talc and gangue minerals, as well as the experience accumulated by workers in selection, which is currently more commonly used. method. The method of sorting by using the different optical properties of talc and impurity mineral surfaces is called photoelectric separation, and this method is now more and more valued and used by enterprises.
After the ore is sorted and stored in the warehouse, it enters the workshop in batches for crushing and coarse powder grinding before ultra-fine grinding: first, hammer crushing, then vertical mill grinding, iron removal treatment, and bagging.
With the advancement of science and technology and the continuous upgrading of market application requirements, finely ground and ultrafinely ground talc has become a benchmark for measuring the quality of talcum powder products. Talc has a Mohs hardness of 1 and is naturally crushable and grindable. At present, there are basically two methods for the ultrafine grinding of talc in the domestic and international markets: one is jet milling and grinding, the other is vertical mill plus grading and sieving grinding; of course, there are other processing methods such as water milling, ring rolling milling, etc., but Neither is mainstream.
First introduce the jet milling grinding process: Coarse powder – jet milling – iron removal – finished powder, the fineness of the final product of fine powder ground in this way can reach 1250-5000 mesh (D97=30-5um).
The second is the production process of vertical mill plus classification: vertical grinding fine powder-classification device screening-1 to 2 level screening-iron removal-finished powder, the fineness of the final product of fine powder ground in this way can reach 1250-2500 mesh (D97=30—8um).
Through the above operation process and standardized working methods, we strictly control the production process of each link, and downgrade the unqualified products in order to meet the quality requirements of 100% product pass rate.
At present, the processing of superfine talc powder mainly adopts dry process.