GB610995A - Method and apparatus for continuous centrifugal decantation - Google Patents

Abstract

610,995. Centrifugal separators. COMPAGNIE DE PRODUITS CHIMIQUES ET ELECTRO-METALLURGIQUES ALAIS, FROGES. ET CAMARQUE. April 18, 1946, Nos. 12029, 12030 and 12031. Convention dates. April 19, 1945, Feb. 21, 1946, and Feb. 27, 1946. [Class 23] Separated solids are removed continuously from a centrifugal separator by means of a carrier liquid which is conveyed to the solids in a radially outward direction and, with the entrained solids moves inward to the discharge. The carrier liquid may be supplied under pressure to the separator by a pump. In a separator of the type shown in Fig. 4, the mixture to be treated is admitted at 6 and the clarified liquid is discharged into a trough 20. The carrier liquid is admitted at 14 passes by pipes 15 to the periphery and carries the entrained solids inwardly through the pipes 5 to a discharge trough 22. The depths of the liquids in the troughs 20, 22 is varied by adjusting the extraction pipes 21, 23. In a separator of the type having a number of cone pieces 2, Fig. 7, the mixture enters by a passage 8 and a perforated partition 10 and the clarified liquid is discharged through a passage 12. The carrier liquid is introduced between the cone's 2, 3 and, entraining the solids at the apex of the cones, carries them inwards through the tube 4 to the discharge passage 5. The passages 5, 12 may lead to discharge troughs or to calibrated orifices. To prevent the movement of the carrier liquid causing a disturbance of the body of liquid in the cone, a flared pipe 38 gathers any inwardlymoving liquid and conveys it to the entry chamber 9. In the form shown in Fig. 10, the separated solids pass into a channel 25. the carrier liquid is spread into a conical sheet by a device 26 and carries the entrained solids into an annular space 27 which leads to the discharge pipe 4. In the form shown in Fig. 8, separated solids reach the cavity 31, the carrier liquid is introduced by the channel 29 and the entrained solids are carried away by the pipe 4. The flow of the materials is regulated by means of a plate 33a. A washing fluid can be introduced through a port 35. The apparatus is described in connection with the separation of the red muds in suspension in solutions of aluminate of soda derived from the treatment of bauxite by the Bayer process. The carrier liquid may be a weak solution of aluminate of soda and may be, later, separated from the red muds for repeated use. The weak liquor may be emulsified in the centrifuge with a gas or vapour. The larger particles of red mud may be separated out by other apparatus before the suspension is introduced to the separator.