The paper industry is the main consumer market for calcium carbonate, and almost all types of paper products need to add calcium carbonate. Both heavy calcium carbonate and light calcium carbonate can be used as fillers in papermaking, which can increase whiteness, enhance air permeability, flexibility and opacity, and improve ink absorption. Heavy calcium is generally used in ordinary paper products such as printing paper, advertising paper, office paper, writing paper, etc., with high cost performance, while in cigarette paper, filter paper, high-quality low-quantity coated printing paper, recording paper and information paper, etc. In the field, light calcium is more competitive because of its better quality than heavier calcium.
However, the unmodified calcium carbonate has poor compatibility and binding force with pulp fibers, and has a low retention rate, which is likely to cause material interface defects and reduce the mechanical strength of the paper. Therefore, both heavy calcium and light calcium carbonate used in papermaking fillers generally need to be modified.
Talc is one of the most traditional inorganic mineral powders in the paper industry. Basically, more than half of the talc output is used in the paper industry. Talc is mainly used as a paper-making filler, and a small part is used as a paper-making resin control agent and paint pigment. Talc is the softest silicate mineral known in the world. It has good lubricity, fire resistance, lipophilic and hydrophobic properties, acid and alkali resistance, electrical insulation and chemical stability, so it is a rare and versatile Mineral materials for papermaking. It can make the paper smooth, heavier, and enhance the absorption capacity of printing inks and pigments.
Different types of talc have different characteristics and are suitable for different paper products. Low-grade talc and its compound processed products will be mainly used for ordinary papermaking fillers; mid-grade talc is mainly used for high-quality functional papermaking fillers and primer coatings; high-quality talc is mainly used for viscous materials that can better reflect its functional characteristics Control agent products and coating grade products. At present, the new talc products that can be used in the paper industry mainly include cationic modified talc, paraffin wax and AKD modified talc, black talc, magnesia-aluminum hydrotalcite, etc.
Kaolin is one of the most consumed white non-metallic mineral materials in the papermaking industry. More than 75% of refined kaolin in the world is used for papermaking. According to forecasts, the national paper industry demand for kaolin in 2020 will be about 2.55 million tons, of which domestic production will account for about 65%. Kaolin is mainly used in papermaking fillers and surface coating pigments in the papermaking industry. Its characteristics have a great influence on the operability of papermaking and the quality of paper. According to different processing methods and product characteristics, kaolin for paper coatings is divided into water-selected kaolin and calcined kaolin.
Among them, calcined kaolin is a functional material for papermaking with high whiteness, porosity and certain adsorption. According to the different sintering temperature, it can be divided into incomplete calcined kaolin (600～800℃) and completely calcined kaolin (950～1050℃). ). The former is mostly used for papermaking fillers, and the latter is mostly used for papermaking coating materials. Its functionality mainly comes from the process of kaolinite (soil) roasting, dehydration and deorganization. The porosity of the structure after roasting can improve the bulk, opacity, and ink absorption of the paper.
Wollastonite is a kind of triclinic chain metasilicate mineral, the aggregates are flake, radial and fibrous. Wollastonite has low ignition loss, good flux, thermal stability and chemical stability. Wollastonite powder has high whiteness, good interface performance and adsorption performance. It is interwoven with pulp fibers to form a network structure. It is mainly used as a filler in the paper industry and can also partially replace plant fibers as a raw material for papermaking. The main methods of wollastonite modification are physical method and chemical method.
Bentonite is a clay mainly composed of montmorillonite and has a typical lamellar structure. Bentonite has strong water absorption, dispersibility, suspension, electronegativity, cation exchange, adhesion and fire resistance. Bentonite, as a kind of hydrolyzable swelling viscous mineral, is usually used as a filter aid in the paper industry and an adsorbent for papermaking wastewater treatment.
When these non-metallic minerals mentioned above are used in the papermaking industry, they all need to go through strict washing and removal of impurities and crushing and grinding processes to reach a certain specific surface area in order to better play their role. The grinding equipment we provide for processing all kinds of non-metallic minerals is energy-saving and efficient, with large processing capacity, less dust and good environmental protection. If you are interested, please contact us for a free design plan and budget evaluation.