摘要 |
Disclosed is (a) a filtration method using (i) micro-bits produced from an expanded thermoplastic polymer non-brittle in expanded form and selected from a styrene-polymer and a polyolefin from polyethylene to poly-methylpentene or (ii) mixtures of these micro-bits and inorganic filter aids as diatomaceous earth and perlite, and (b) these filter aid mixtures. These micro-bits and mixtures are useful filter aids in several different ways. One is to prepare a slurry of them in a liquid medium and feed this slurry to a filter element (as fabric filter cloth or wire filter cloth or ceramic filter) to provide on that element's feed side a precoat of the filter aid and liquid leaves as filtrate from its filtrate side. In another way these micro-bits and mixtures are used by being admixed into the liquid (inert to them) containing finely divided material suspended or dispersed in the liquid and to be removed. Also, these micro-bits alone or mixture with diatomaceous earth or perlite can be admixed into the liquid medium. Another way to use the micro-bits or their mixture is by using the precoat route and with the liquid dispersion to be filtered containing in it these micro-bits alone or admixed with any inorganic filter aid.
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