The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 12, 1982
Filed:
Nov. 08, 1977
Karl Achenbach, Frankfurt, DE;
Gunter Turk, Hanau, DE;
DEGUSSA, Frankfurt, DE;
Abstract
Silicon dioxide containing waste flue dust from the production of silicon metal and silicon alloys is converted to crystalline zeolite molecular sieves of type A by (1) dissolving the flue dust in alkali metal hydroxide solution with the formation of alkali metal silicate solution having a module (SiO.sub.2 :Me.sub.2.sup.I O) in the range of 2.0:1 to 3.5:1 at a temperature of 60.degree.-100.degree. C.; (2) purifying the thus obtained alkali metal silicate solution from organic constituents by treatment with activated carbon and/or an oxidizing agent and separating the non-decomposable residue from the solution; and, (3) reacting alkali metal aluminate solution present at room temperature with the diluted, purified alkali metal silicate solution with a module (SiO.sub.2 :Na.sub.2 O) of 2.0:1 to 3.5:1 obtained by steps (1) and (2) and subsequently crystallizing the reaction mixture ((2.0-4.4)Na.sub.2 O:Al.sub.2 O.sub.3 ; (1.3-1.8)SiO.sub.2 :(90-120)H.sub.2 O) at a temperature of 90.degree.-95.degree. C. for a period of 6-12 hours, subsequently filtering, washing to pH of about 10-11 and drying to recover a crystalline, zeolitic molecular sieve of type A having a degree of whiteness according to Berger (A. Berger, Die Farbe 8 Nr. 4/6 (1959) pages 187-202) at 460.mu. in the range of 90-95%.