ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Suspended Particle Circulation in Gas-Lift Tanks

K. Wichterle and L. Obalová

VŠВ-Technical University Ostrava, CZ-708 33 Ostrava Poruba, Czech Republic

E-mail: wihl5@vsb.cz

Abstract: Introduction of gas to liquid in a vertical tube results in a hold-up of bubbles and related decrease of average density. It can be employed in air-lift pumps for transporting liquid upwards or in a closed loop to agitate liquid in gas-lift reactors. Popular equipment of hydrometallurgy is a pachuca tank, large slender cylinder with an air-lift riser in central position. It is used for leaching processes, where abrasive particles are handled in large volumes of extremely corrosive liquids, and therefore moving parts should be avoided. Amount of gas, required to agitate liquid efficiently and to keep solid particles suspended is an important quantity. Suggested model takes into consideration rising velocity of bubbles, settling velocity of particles, and pressure loss. Friction coefficient is determined from pilot plant data with air-water system. Superficial velocity of liquid as a function of gas flow rate for pure liquids and superficial velocity of solid particles as a function of gas flow rate for the settling suspensions are results of the simulation of the process. Power input and its fraction employed to keeping particles suspended, i.e. efficiency of the suspension is discussed.

Full paper in Portable Document Format: 536a384.pdf

Chemical Papers 53 (6) 384–389 (1999)