# US 2019/0169491 A1 · Fracking proppant and method of manufacture > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0169491 A1 - Document ID: US20190169491A1 - Status: Published application - Kind: A1 - Application number: 16/324,843 - Filed: 2017-08-11 - Published: 2019-06-06 - Earliest claimed: 2016-08-11 - Assignees: Dynamic Material Systems, LLC - Applicants: Dynamic Material Systems LLC - Inventors: Arnold Hill; William Easter - Web page: https://patentgrep.com/patent/US20190169491A1 ## CPC - C09K 8/805: {Coated proppants} - C04B 35/528: obtained from carbonaceous particles with or without other non-organic components - C04B 35/62204: {using waste materials or refuse (clay-wares containing waste materials C04B33/132)} - C04B 35/62272: {based on non-oxide ceramics (carbon nanotubes C01B32/15; carbon fibers D01F9/12)} - C04B 35/62655: {Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying} - C09K 8/80: Compositions for reinforcing fractures, e.g. compositions of proppants used to keep the fractures open - E21B 43/267: reinforcing fractures by propping - C04B 2235/3826: Silicon carbides - C04B 2235/3895: Non-oxides with a defined oxygen content, e.g. SiOC, TiON - C04B 2235/483: Si-containing organic compounds, e.g. silicone resins, (poly)silanes, (poly)siloxanes or (poly)silazanes - C04B 2235/486: Boron containing organic compounds, e.g. borazine, borane or boranyl - C04B 2235/5248: Carbon, e.g. graphite - C04B 2235/5284: Hollow fibers, e.g. nanotubes - C04B 2235/5288: Carbon nanotubes - C04B 2235/5296: with a defined aspect ratio, e.g. indicating sphericity - C04B 2235/5427: millimeter or submillimeter sized, i.e. larger than 0,1 mm - C04B 2235/5436: micrometer sized, i.e. from 1 to 100 micron - C04B 2235/6562: Heating rate - C04B 2235/6586: Processes characterised by the flow of gas - C04B 2235/77: Density - C04B 2235/80: Phases present in the sintered or melt-cast ceramic products other than the main phase - C04B 2235/94: Products characterised by their shape - C04B 2235/96: Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance - C09K 2208/08: Fiber-containing well treatment fluids - C09K 2208/10: Nanoparticle-containing well treatment fluids - C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE - 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 - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS ## Abstract A material useful as a proppant comprises a core chemically reacted in situ from coal dust and a polymer derived ceramic material, such that at least a portion of the coal dust is chemically converted to a ceramic, nanoparticles, graphene, nanofibers or combinations of any of these. ## Claims ### Claim 1 A material useful as a proppant comprises: a plurality of particles or rods comprised of a pyrolyzed mixture of coal dust and polymer derived ceramic material, wherein the coal dust comprises carbon and water and is mixed with the polymer derived ceramic material to form a composite mixture, prior to pyrolysis, and the composite mixture is formed into the plurality of particles or rods prior to pyrolysis; and during pyrolysis, a substantial portion of the coal dust chemically reacts, in situ, forming, after pyrolysis is complete, ceramic, graphene, nanotubes, or nanofibers or any combination of ceramic, graphene, nanotubes or nanofibers, such that the plurality of particles or rods comprise a porous ceramic composite after pyrolysis. ### Claim 2 (depends on 1) The material of claim 1, wherein the composite mixture comprises no less than 40 wt % and no greater than 90 wt % coal dust, and the polymer derived ceramic material comprises at least the elements silicon, oxygen and carbon. ### Claim 3 (depends on 2) The material of claim 2, wherein the composite mixture comprises no less than 10 wt % polymer derived ceramic material and no greater than 60 wt % polymer derived ceramic material. ### Claim 4 (depends on 1) The material of claim 1, wherein the coal dust is derived from a source of coal by pulverizing, crushing, milling or any combination of pulverizing, crushing or milling. ### Claim 5 (depends on 1) The material of claim 1, wherein the coal dust is first sorted by centrifuging, screening or filtering, such that the coal dust is selected to have a uniform particle size range. ### Claim 6 (depends on 1) The material of claim 1, wherein the coal dust comprises a source of carbon and volatile organics and water, and the carbon, volatile organics and water chemically react in situ when mixed with polymer derived ceramic material during pyrolysis. ### Claim 7 (depends on 6) The material of claim 6, wherein the composite mixture comprises a source of iron, and while the composite mixture is being pyrolyzed, the iron acts as a catalyst for the growth of nanotubes, graphene, nanofibers or any combination of nanotubes, graphene or nanofibers. ### Claim 8 (depends on 7) The material of claim 7, further comprising an external layer of pyrolyzed polymer derived ceramic material substantially free of coal dust particles. ### Claim 9 (depends on 1) The material of claim 1, wherein the sphericity of the plurality of particles is greater than 0.9. ### Claim 10 (depends on 9) The material of claim 9, wherein the compressive fracture strength of the plurality of particles is at least 2000 psi. ### Claim 11 (depends on 9) The material of claim 9, wherein the compressive fracture strength of the plurality of particles is at least 5000 psi. ### Claim 12 (depends on 9) The material of claim 9, wherein the compressive fracture strength of the plurality of particles is at least 10,000 psi. ### Claim 13 (depends on 1) The material of claim 1, wherein the particle size (PD50) of the plurality of particles is in a range from 10 microns to 1000 microns. ### Claim 14 (depends on 1) The material of claim 1, wherein the particle size (PD50) of the plurality of particles is in a range from 20 microns to 500 microns. ### Claim 15 (depends on 14) The material of claim 14, wherein the compressive fracture strength of the plurality of particles is at least 2000 psi. ### Claim 16 (depends on 15) The material of claim 15, wherein the plurality of particles are selected with a median particle size (PD50) from 50 microns to 200 microns and exhibit a compressive fracture strength of at least 5000 psi. ### Claim 17 (depends on 16) The material of claim 16, wherein the median density of the plurality of particles, after pyrolysis is no less than 1.3 g/cc and no greater than 1.8 grams per cubic centimeter. ### Claim 18 (depends on 1) The material of claim 1, wherein the plurality of particles each have a ceramic shell substantially devoid of coal dust and have a compressive fracture strength in a range from 6000 psi to 20,000 psi. ### Claim 19 (depends on 18) The material of claim 18, wherein the ceramic shell is substantially nonporous and the core comprises a cancellous ceramic network. ### Claim 20 (depends on 1) The material of claim 1, wherein the weight percentage of the weight of coal dust to the weight of the mixture of coal dust and polymer derived ceramic material is selected in a range from 60 wt % to 80 wt % within a core portion of the proppant. ### Claim 21 (depends on 1) The material of claim 1, wherein the coal dust is pulverized to less than 3 microns. ### Claim 22 (depends on 1) The materials of claim 1, wherein the median density of the plurality of particles is less than 1.5 g/cc. ### Claim 23 A material useful as a proppant comprises: a plurality of extruded, elongated rods having a rod length much greater than a rod diameter, each of the rods being comprised of a mixture of coal dust and polymer derived ceramic material, when initially extruded prior to pyrolysis, wherein the coal dust comprises carbon and water and is mixed with the polymer derived ceramic material to form a composite mixture, the composite mixture being extruded under pressure into rods; and during pyrolysis, a substantial portion of the coal dust chemically reacts, in situ, forming, after pyrolysis is complete, ceramic, graphene, nanotubes, or nanofibers or any combination of ceramic, graphene, nanotubes or nanofibers, such that the plurality of rods comprise a porous ceramic composite after pyrolysis. ### Claim 24 (depends on 23) The material of claim 23, wherein the rods each have a core disposed within an outer shell having a higher density than the core, and substantially all of the coal dust is chemically reacted in at least a portion of the core, such that the portion of the core is a ceramic substantially devoid of unreacted coal dust.