Patent ID: 6193075
Filing Date: 2001-02-27
Classification: B07B

Abstract:
A method of separating the substantially similarly sized high and low ash fractions of rendered animal meal to obtain yields of the low ash fraction greater than about 50% by weight, wherein the low ash fraction contains less than about 11% by weight ash, the method comprising:(a) introducing to a primary air cyclone separator a rendered animal meal, the primary air cyclone separator having: (i) a chamber provided with means to create a double air vortex, the double vortex including a first axially downward air vortex proximate to the chamber walls and a second axially upward air vortex located central to the first axially downward air vortex; and (ii) a rotary particle rejector supported for rotation about a vertical axis, the rotary particle rejector being equipped with a set of blades radially aligned vertically along the rotary particle rejector perimeter and wherein the spacing from blade longitudinal center to blade longitudinal center is at least about 2.5% of the rotary particle rejector circumference;(b) operating the rotary particle rejector at a rotational speed between about 75 and about 300 rotations per minute;(c) entraining the low ash fraction in the upward air vortex;(d) passing the air entrained low ash particles to a secondary air separator means to recover the low ash fraction; and(e) recovering means to recover the high ash balance of the rendered animal meal from the primary air cyclone separator.