GB503352A - Method for the continuous preparation of superphosphates - Google Patents

Abstract

503,352. Endless-belt conveyers. GAUNT, J. G. (Compagnie Nationale de Matieres Colorantes et Manufactures de Produits Chimiques du Nord Reunies, Etablissements Kuhlmann) Dec. 11, 1937, No. 34380. [Class 78 (i)] [Also in Groups III and II] Superphosphates are prepared from raw phosphate and sulphuric or phosphoric acid by continuously supplying phosphate and acid to a mixer adapted to entrain air into the mixture to form a foam and discharging the foam on to an endless band conveyer in a thin layer where it forms a highly porous solid which is thereafter disintegrated. Suitable apparatus shown in the Figure comprises a weighing device 3 for crushed phosphate and a measuring device 9 for acid both discharging into the mixer 6 and both being driven from a common motor. The foam formed falls on to the endless belt 11 which is supported on rollers 25, which are spaced more closely near the mixer to ensure the perfect horizontality of the belt. Other rollers 26 support the lower strand and are cleaned by spring-urged blades 27. The fluid gradually solidifies during its passage along the belt until it reaches the disintegrator 14. The latter cuts the solidified foam into flakes which fall on to the conveyers 15 and 16 for air drying and then to the elevator 17 for further processing. In order to prevent loss of material over the sides of the belts the upper rollers may be in three parts forming the belt into a concave shape. To prevent the liquid flowing over the side of belt 11 before it has had time to solidify, flanges, separate from the belt, made from wood with rubber linings may be placed on either side of the belt and in fluidtight contact therewith. To prevent clogging they may be suspended by spring blades 31 and be connected to bearings 32 in which a shaft-having an eccentric weight revolves.