METHOD FOR PRODUCING STARCH BY MEANS OF WET MILLING MAIZE FOR REGENERATING WASTE ROCK PILES CONSISTGING OF SAND

摘要

High-rate washing centrifuges are employed in a corn wet milling process to accomplish displacement washing of the starch and a sharp classification into starch and gluten. A Starch-Gluten Separation Station (C) directs the mixed starch-containing feed flow stream having a density of from 6 DEG Be to 12 DEG Be from an attrition mill of a stepping and Germ Separation Station (A) and a Fiber Washing and dewatering Station (B) directly to a first high wash rate classification centrifuge (61) capable of classifying the feed stream into a gluten-rich overflow stream which includes soluble protein and an underflow starch-rich stream. The flow of wash in the centrifuge is substantially completely countercurrent to the flow of feed solids, so as to effect separation of the gluten and starch components. The gluten-rich stream is forwarded to a gluten-thickening centrifuge (81) in which the overflow is process water and the gluten-rich underflow exits the Station for dewatering and further treatment. The starch-rich underflow stream of the first classification centrifuge is forwarded to a second high wash rate classification centrifuge (67) wherein the wash, supplied in a wash liquid to draw-off volume ratio in the range of 1 to 2, is countercurrent to flow of feed solids and wherein the overflow stream thereof contains a minor protein component and is in part returned to said first classification centrifuge (61) as wash liquid and in part is returned to the Fiber Washing Station (B) as process water. The starch-rich underflow at a density of from 14 DEG Be to 22 DEG Be is forwarded to the Starch Washing and Thickening Station (D) where it is subjected to treatment in multistage hydrocyclones with the overflow from the stages injected as wash liquid into said second classification centrifuge (67) and the underflow constituting the starch product. IMAGE