Apparatus and process for continuous concentration and washing of solids

Abstract

Apparatus for concentrating and washing solids in a slurry comprising a housing containing both separation/concentration and washing chambers with an inlet for continuously injecting solids -- containing fluid into the separation chamber wherein a dynamic filtering system is provided for separating the solids -- containing fluid to form a cencentrate of solids and a filtrate. The filtering system includes a plurality of stationary filter elements and a plurality of rotor elements mounted on a rotatable shaft from which they extend outwardly and adjacent the filter elements to form a plurality of alternating rotor and filter elements within the housing. The concentrate washing chamber is disposed downstream of the filtering system and includes a plurality of stationary filter elements and a plurality of rotor elements arranged similarly to the elements in the filtering system. The washing chamber also includes means for introducing and commingling a wash fluid with the concentrate to remove impurities therefrom by dissolving said impurities or diluting the liquid containing them and then removing the liquid by further filtration. One embodiment is described wherein a single continuous upstream injection and continuous downstream removal of wash fluid is provided in the washing chamber. Another embodiment comprises a continuous downstream injection with continuous removals and reinjections of wash water in sections progressing in an upstream direction from the initial downstream injection until final withdrawal at the extreme upstream section of the washing chamber. In still another embodiment fresh wash fluid is simultaneously injected and removed continuously in each of a plurality of separate sections of the washing chamber.