Development status and characteristics of high-efficiency mixing granulators used in the calcium carbonate industry

The overall requirements for granulators used in the calcium carbonate industry are high thermal efficiency, low energy consumption, simple configuration, easy control, small footprint, and safe and hygienic operating environment. At present, the efficient mixing granulators commonly used in the inorganic salt industry are: rotary tubular dryer, rotary indirect heating dryer, disc continuous dryer, airflow dryer (also divided into pulse airflow, airflow rotation, positive and negative pressure two-stage airflow drying), rotary flash dryer, rotary drum dryer, spray dryer (also divided into granulation, powder, centrifugal, pressure type), vibrating fluidized bed dryer, static vacuum dryer, hot air circulation oven, rake, paddle vacuum dryer, boiling dryer (horizontal, vertical), etc.

These efficient mixing granulators provide a guarantee for product quality, but they all have the problem of exhaust gas dust collection. Due to the continuous increase of nanoscale products, the original particle size is becoming finer and finer, and the potential moisture content of paste like materials is increasing. In addition, enterprises are constantly developing towards large-scale and scalable directions, and they are eager to combine high-efficiency mixing granulators. Especially for some large tonnage products, such as precipitated calcium carbonate, the current national production capacity is over 3 million tons, with a production line annual output limit of 10000 tons. For a scale of 100000 tons, five sets of high-efficiency mixing granulators are needed. A company in Guangxi plans to increase the capacity to 500000 tons. Based on the current level of high-efficiency mixing granulators, both the equipment footprint and the amount of exhaust gas dust collected after product drying are significant.

According to the widely used pulse bag filter in the industry, the operating environment is very harsh and effective measures must be taken to solve it. Therefore, we hope that the equipment development unit can focus on solving two problems: first, the drying problem of paste like fine objects with high water content, and second, the industrial hygiene problem of collecting "dust" from exhaust gas after object drying. Taking the calcium carbonate industry as an example, more than 200 enterprises across the country basically use rotary indirect heating drying machines, disc continuous drying machines, rotary tube drying machines, etc. in the selection of efficient mixing granulators. Although the production efficiency is met, the energy consumption and exhaust gas collection are not ideal. When entering the calcium carbonate enterprise, a layer of white calcium carbonate powder is covered from the ground to the roof, and even on the desks and chairs in the office, there are management problems. More importantly, the exhaust gas collection after drying is not up to standard. Recently, the industry has introduced dust removal equipment produced by DuPont, which has basically solved the problem.
Therefore, the combination of high-efficiency mixing granulators should include: providing heat source equipment, first and second stage high-efficiency mixing granulators, exhaust gas collection "dust" equipment, etc. It is hoped that equipment manufacturing and research units will make efforts in high thermal efficiency, low energy consumption, simple configuration, and convenient control, and in the combination of high-efficiency mixing granulators, serving others and developing themselves. If the drying problem in the calcium carbonate industry is solved and equipment efficiency and environmental friendliness are achieved, the drying problems of other varieties will be easily solved.