The new system reportedly makes it possible to dry grind material to particle sizes in the submicron range with considerably improved performance.

NETZSCH-CONDUX Mahltechnik GmbH, along with Roland Nied, Ph.D., a renowned particle processing technology scientist, recently developed the S-JET® System (patent pending), which makes it possible to dry grind material to particle sizes in the submicron range with considerably improved performance. The mechanical requirements are fulfilled by the company’s CGS fluidized bed jet mill.

“To increase the energy needed to pulverize material, we changed the type of gas we use from air to steam,” said Thomas Schneider, marketing manager of NETZSCH–CONDUX. “Superheated steam is already being used as a grinding medium in older spiral jet mills without an integrated air classifier. These jet mills leave an oversized residue, meaning that no defined particle sizes in the nano-range could be achieved. This is not the case when it comes to our S-JET System.

“Simply stated, superheated steam provides two considerable advantages. First, jet streams of up to 1.200 m/s can be obtained with steam, whereas the upper limit obtained with air is about 600 m/s. This increases the kinetic impact energy of the particles in the fluidized bed fourfold, whereby they can be pulverized to a nano-scale. Second, the speed of sound of steam is approximately 550 m/sec, while that of air is only 330 m/sec. This increases the possible circumferential speeds of the classification current inside the dynamic classifier wheel and the force of acceleration on the particles. This effectively results in a finer cut point, allowing classification into the nanometer range.”

Benefits include high finenesses (< 1 micron), throughput capacity, efficiency, product purity and yields; the processing of difficult products; optimum product performance; steep particle size distribution; and contamination-free grinding.

For more information, call (49) 06181-50601, fax (49) 06181-57127000 or e-mail info@ncx.netzsch.com.