| 摘要 |
<p>507,791. Paper pulp. McGREGOR, E. T. March 22, 1938, No. 8783. [Class 2 (ii)] For producing a de-inked paper stock from printed paper, the latter after soaking in water, is agitated with a solution of trisodium phosphate at or below atmospheric temperature. After agitation, it is convenient to add such a quantity of water as will cause the oil, carbon &c. to float to the surface, whereupon these impurities are drained off. After separation the pulp is washed, pressed, &c., and the solution is filtered, strengthened and returned for re-use. Reference has been directed by the Comptroller to U.S.A. Specification 1,933,228.</p> |
