GB853928A - Preparation of dustless starch - Google Patents

Abstract

In gelatinizing and drying starch to render it dustless and readily dispersible in cold water, moist starch, containing between 25 and 45% of water and, if desired, hydrochloric or sulphuric acid or aluminium chloride, is conveyed through a flash dryer in a current of air having, at the inlet for the starch, a wet bulb temperature ranging between 170 DEG and 212 DEG F. and a dry bulb temperature within the range of the wet bulb temperature and the temperature at which the starch decomposes, and the gelatinized and dried starch is then separated from the air. The flash dryer may comprise a duct in which gelatinization and drying of the starch takes place. The starch and air, and if necessary, steam may be fed into the duct through a mechanical disintegrator such as a pin mill and passed through the duct into a cyclone, wherein the separation of starch from air is effected. The minimum dry bulb temperatures of the air fed into the mechanical disintegrator and the air leaving the cyclone may be 318 DEG and 213 DEG F., respectively. The separated air may be returned to the mechanical disintegrator through another cyclone, into which water is sprayed, a fan and a heater. Modified starches, starch ethers and esters and dextrins may be treated according to the invention. Specifications 468,830, 474,320 and U.S.A. Specification 1,899,952 are referred to.