DEVELOPMENT OF HIGH PRESSURE FILTRATION CLOTHS

摘要

In targeting economical solid-liquid separation,it can be optimal to aim for filter cakes with as low a moisture content as possible from the first stage of filtration.In some cases,if it is possible to filter the cake mechanically to a moisture content of less than 30 %,for example,the product can be further processed without a need for further dewatering cycles.One way to take the conventional filtration process further and to reach a considerably lower filter cake moisture content is to raise the filtration pressure gradually to an exceptionally high level,such as 140 bar.This paper focuses on the high pressure filtration of calcium carbonate,which is not easily filtered given its average particle size of 1.2 mum,and also on the impact of different cloths on filtration efficiency.Typical problems with high pressure dewatering techniques include the adherence of the cake to the filtration medium,mechanical breakdown or folding of the filtration medium in the filter and premature blinding of the filtration medium.If the performance of the filtration medium can be ensured in a high pressure filter in the same way that cloths function in conventional filters,high pressure filtration could provide major economic benefits in a number of conventional liquid-solid separation applications.