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:
Jun. 18, 2013
Filed:
Aug. 03, 2011
Mark J. Ziegler, Rockford, IL (US);
Mark J. Ziegler, Rockford, IL (US);
Unimin Corporation, New Canaan, CT (US);
Abstract
A method of making frac sand having a selected grade from a naturally occurring, mined sand having a SiOcontent of at least about 80 percent and having a particle size range where the maximum particle size is less than about 8.0 mm, comprising: crushing the mined sand into an intermediate particulate material; screening the particulate material into a feedstock with particles having a particle size coarser than about 350 mesh and initial values for roundness and sphericity of the particles; passing the particles of the feedstock through a blast tube with an outlet to pneumatically abrade the particles and propel the feedstock in a stream under a given pressure from the outlet; directing the pressurized stream against a fixed target located at a given distance from said outlet to physically abrade the particles to form an output mass containing abraded particles: and, repeating operations (c) and (d) a number of times or process stages until the particles resulting from the repeatedly abraded output mass is a final output mass having both processed roundness and sphericity values of at least 0.6 and wherein the values are greater than the initial values of the feedstock by at least about 0.10 to 0.50.