Chang'an Renheng is a company engaged in the mining, research and development, production, sales, and after-sales service of bentonite minerals. It has formulated 4 industry standards and completed the acceptance of 7 provincial-level new product development projects. The company has established a complete set of quality management, environmental management and other systems, and has passed the certifications of ISO9001:2015 quality management, ISO14001:2015 environmental management, ISO45001:2018 occupational health and safety management and other systems. The company holds a mining license for a bentonite mine and has a reserve of approximately 2 million tons of exploitable bentonite resources. The company has two major production bases in China, with an annual output of over 60000 tons of bentonite series products for various purposes, ranking first in the domestic retention agent industry for several consecutive years

Chang'an Renheng is also constantly optimizing and extending its new products, such as bentonite for papermaking binary particle retention and filtration aids

What is papermaking retention and filtration aid

Paper retention and filtration aid is a water-soluble branched organic polymer. The function of paper retention and filtration aid is to increase the retention rate of pulp when it is online, and it has excellent retention effects on fine fibers and fillers (such as calcium carbonate, titanium dioxide, and kaolin), resulting in significant pulp saving. Enhance water filtration and reduce dehydration energy consumption during forming, pressing, and drying processes. Thus increasing paper production, reducing energy consumption, and lowering costs. Moreover, it has the function of increasing the strength of wet and dry paper, maintaining stable wet end chemical conditions, improving paper uniformity and physical properties. Due to the reduction in the amount of fine fibers and fillers in the effluent, the load on wastewater treatment has also been reduced

In papermaking production, fillers are the most commonly used auxiliary materials, with particle sizes generally ranging from 0.2-10 µ m. The copper mesh used in paper machines has a relatively large mesh size of 40-100 mesh, equivalent to 150-250 µ m. Generally, during the copying process, only about 50% of the filler is retained, and the remaining half will be lost with the white water. Retention aids have coagulation and flocculation effects, so they are used to improve the retention rate of fine fibers and fillers in paper materials, and reduce the solid content of fine materials in water.

There are many types of retention aids, which can be divided into inorganic substances, organic high molecular weight polymers, and surfactants according to their structure and physical properties. Among them, there are 23 types of retention aids for organic high molecular weight polymers, mainly derivatives of organic amine (ammonium) salts, as well as polyethylene oxide (PEO), starch, etc. Among them, polyacrylamide is the most representative.

Filter aid is a chemical added to improve the water filtration and dehydration speed of wet paper from the papermaking web. Filter aids can mainly cause fine fibers to coagulate on the fiber surface, reducing the clogging of wet paper pores and increasing permeability. The filtering effect and retention effect are interconnected in promoting dispersion and flocculation. So there are many similarities between the two in terms of performance. The main types of filter aids include polyethyleneimine, polyacrylamide, polyaminamide, cationic ethylene series polymers, etc. The initial filter aid used was polyethyleneimine. Later, due to the price reduction of polyacrylamide and the development of various modified polyacrylamide, the application of PAM gradually became the main focus