Issue link: https://www.e-digitaleditions.com/i/1197147
58 / January 2020 powderbulk.com Case history | New pins bring added abrasion resistance to agglomerator PBE A bentonite processing facility switched to more robust pins to cut back on maintenance time. B lack Hills Bentonite, Casper, WY, mines and processes sodium bentonite and lignite at several facilities. Depending on how bentonite is processed, the end product can be used in a wide range of industries, including drilling applications, metal casting, environ- mental and civil engineering appli- cations, and as an absorbent. Pelletizing bentonite Due to the material's highly absor- bent characteristics, pelletized sodium bentonite can be used in cat litter production. One of Black Hills Bentonite's plants has been producing material for cat litter since 1990 with the help of a Mars Mineral pin mixer (also known as a pin agglomerator). The pin mixer is a high-speed, high-energy processor that com- pacts particles into small agglomer- ates or pellets. The unit has a long, cylindrical shell with a shaft in the middle with radially extending rows of pins attached. The pins are arranged in a double-helical pattern that's staggered and overlapping to ensure uniform particle processing. The raw, mined bentonite is sent through a rotary dryer and then enters the pin mixer along with a fine spray of liquid as a binder to aid in the agglomeration process. The material is whipped around by the pins as the bentonite moves through the shell. Once the benton- ite is compacted into small pellets, the material exits the pin mixer and is screened before moving on for further processing. Material that doesn't pass through the screens is recycled back into the process until it fits the company's specifications. While the pin mixer has remained in place for more than 30 years, the pins that move the mate- rial around inside the mixer have This pin mixer has been in operation at Black Hills Bentonite for more than 30 years. The company recently switched to new pins to increase time between maintenance.