Union Process, Inc. has built an S-400 batch, wet-grinding Attritor for a customer in the roofing industry. The S-400 represents the largest batch Attritor ever built by the 66-year-old company. Batch Attritors have the advantage of grinding material up to ten times faster than traditional ball mills. They are simple to operate, energy efficient and do not require premixing. This Attritor has a new frame design utilizing a pivoting drive cantilever, which allows for easy removal of the agitator shaft for maintenance and cleaning. The Attritor features a 400 HP TEFC inverter duty motor with a heavy-duty variable frequency drive controller. The large tank accommodates 12,000 lbs. of through-hardened carbon steel grinding media.