# US 8,464,969 B2 · Method of making proppants used in gas or oil extraction > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,464,969 B2 - Document ID: US8464969B2 - Status: Granted - Kind: B2 - Application number: 13/197,520 - Filed: 2011-08-03 - Published: 2011-12-01 - Granted: 2013-06-18 - Earliest claimed: 2008-09-20 - Assignees: Unimin Corporation - Applicants: Mark J. Ziegler - Inventors: Mark J. Ziegler - Web page: https://patentgrep.com/patent/US8464969B2 ## CPC - C09K 8/80: Compositions for reinforcing fractures, e.g. compositions of proppants used to keep the fractures open - B02C 19/066: {of the jet-anvil type (B02C19/068 takes precedence)} - B03B 9/00: General arrangement of separating plant, e.g. flow sheets - C04B 14/06: Quartz; Sand - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - B02C: CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN ({household tools and machines for pulverising foodstuffs, e.g. coffee and spice mills A47J42/00; pharmaceutical mortars A61J3/02; mechanical processing of refuse and garbage B03B9/06; dressing mould materials by grinding B22C5/04}; obtaining metallic powder by crushing, grinding or milling B22F9/04; {recovery of plastics by disintegrating B29B17/00; crushing raw materials in starch making C08B30/02; beaters for papermaking D21D1/02; crushing devices specially for transport in mines E21F13/002; slag crushing devices F23J1/00; fuel milling devices in combustion apparatus F23K1/00; household devices for crushing coal F24B15/02; ice disintegrating devices F25C5/02}) - B03B: SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS - C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE ## Abstract A method of making frac sand having a selected grade from a naturally occurring, mined sand having a SiO2 content 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. ## Claims ### Claim 1 A method of making a proppant from a naturally occurring, mined granular mineral having a hardness over 6.0 Mohs, said method comprising: (a) converting said granular mineral into a feedstock of particles having a maximum particle size and a given sphericity; (b) subjecting said feedstock to a high velocity mechanical action to increase the sphericity of the particles of said feedstock; (c) continuing said high velocity mechanical operation for a time to convert said given sphericity of said particles of said feedstock into a proppant with a processed sphericity greater than 0.60. ### Claim 2 (depends on 1) The method as defined in claim 1 wherein said high velocity mechanical action includes abrading said particles by particle-to-particle contact. ### Claim 3 (depends on 2) The method as defined in claim 2 wherein said high velocity mechanical action includes impinging said particles at high velocity against a metal member. ### Claim 4 (depends on 3) The method as defined in claim 3 wherein said metal member is fixed. ### Claim 5 (depends on 2) The method as defined in claim 2 wherein said processed sphericity is greater than about 0.80. ### Claim 6 (depends on 2) The method as defined in claim 2 wherein said proppant is frac sand and said mineral is silica sand. ### Claim 7 (depends on 6) The method as defined in claim 6 wherein said silica sand has at least 80% SO2. ### Claim 8 (depends on 2) The method as defined in claim 2 including: (d) screening said proppant into a selected grade. ### Claim 9 (depends on 1) The method as defined in claim 1 wherein said high velocity mechanical action includes impinging said particles at high velocity against a metal member. ### Claim 10 (depends on 9) The method as defined in claim 9 wherein said metal member is fixed. ### Claim 11 (depends on 1) The method as defined in claim 1 wherein said processed sphericity is greater than about 0.80. ### Claim 12 (depends on 1) The method as defined in claim 1 wherein said proppant is frac sand and said mineral is silica sand. ### Claim 13 (depends on 12) The method as defined in claim 12 wherein said silica sand has at least 80% S1O2. ### Claim 14 (depends on 1) The method as defined in claim 1 including: (d) screening said proppant into a selected grade. ### Claim 15 (depends on 14) The method as defined in claim 14 wherein said selected grade has a maximum size of 6-35 mesh and a minimum size of 20-140 mesh. ### Claim 16 (depends on 14) The method as defined in claim 14 wherein said selected grade has a maximum size in the range of 12-20 mesh and a minimum size in the range of 30-50 mesh. ### Claim 17 (depends on 1) The method as defined in claim 1 wherein said high velocity mechanical action involves moving said feedstock at a high velocity. ### Claim 18 (depends on 17) The method as defined in claim 17 wherein said high velocity mechanical action includes impinging said particles at high velocity against a metal member. ### Claim 19 (depends on 18) The method as defined in claim 18 wherein said processed sphericity is greater than about 0.80. ### Claim 20 (depends on 18) The method as defined in claim 18 wherein said proppant is frac sand and said mineral is silica sand. ### Claim 21 (depends on 20) The method as defined in claim 20 wherein said silica sand has at least 80% S1O2. ### Claim 22 (depends on 18) The method as defined in claim 18 wherein said metal member is fixed. ### Claim 23 (depends on 17) The method as defined in claim 17 wherein said processed sphericity is greater than about 0.80. ### Claim 24 (depends on 17) The method as defined in claim 17 wherein said proppant is frac sand and said mineral is silica sand. ### Claim 25 (depends on 24) The method as defined in claim 24 wherein said silica sand has at least 80% S1O2. ### Claim 26 (depends on 17) The method as defined in claim 17 including: (d) screening said proppant into a selected grade. ### Claim 27 (depends on 1) The method as defined in claim 1 wherein said mineral is naturally occurring olivine.