Patent ID: 9302209
Filing Date: 2016-04-05
CPC Classification: B01D

Claim Text:
1. A filter medium for removing metal fines and soap from a working liquid used during a metal forming process, the working liquid further comprising a mineral oil and additives for the metal forming process, the filter medium consisting essentially of: a carrier that is inert in the working liquid, is non-toxic, and selected from the group consisting of cellulosic material, synthetic fibers, clay, diatomaceous earth and kieselguhr; and a phosphorous based acid selected from the group consisting of phosphoric acid, polyphosphoric acid, phosphorous pentoxide, and mixtures and/or derivatives thereof, wherein the phosphorous based acid is chemically bonded to the carrier in a manner that prevents elution or separation of the phosphorous based acid from the carrier when in the presence of water or aqueous contaminants present in the working liquid, wherein an amount of the phosphorous based acid in the filter medium is from about 10 wt. % to about 70 wt. %, wherein the metal working liquid containing the metal fines and soaps is filtered through the filter medium to remove the metal fines and soaps and to react with and de-saponify the soaps, the phosphorous based acid being gradually exhausted or used up in chemical reactions with the metal fines and soaps.