Functional composite particles

Abstract

A complex proppant particle is made of a coal dust and binder composite that is pyrolyzed. Constituent portions of the composite react together causing the particles to increase in density and reduce in size during pyrolyzation, yielding a particle suitable for use as a proppant.

1 . Particles each comprise a core comprised of a first material, wherein the first material is a composite made of a coal dust and a polymer derived ceramic material, the coal dust and the polymer derived ceramic material being pyrolized in a substantially non-oxidizing atmosphere and transforming into a ceramic matrix composite, wherein the coal dust of the core is preheated in a substantially non-oxidizing atmosphere at a temperature less than 200 degrees centigrade to produce an additive comprising carbon and organic compounds that vaporize and react when pyrolized in the presence of the polymer derived ceramic material. 
     
     
         2 . (canceled) 
     
     
         3 . The particles of  claim 1 , further comprising a coating substantially enclosing the core within the coating. 
     
     
         4 . The particles of  claim 3 , wherein the coating is comprised of a polymer derived ceramic material, whereby the coating may be comprised of the same polymer derived ceramic material as the polymer derived ceramic material of the core or a different polymer derived ceramic material than the polymer derived ceramic material of the core. 
     
     
         5 . The particles of  claim 4 , wherein the polymer derived ceramic material of the core is a silicon-oxy-carbide polymer derived ceramic material. 
     
     
         6 . The particles of  claim 5 , wherein the polymer derived ceramic material of the coating is the same as the polymer derived ceramic material of the core. 
     
     
         7 . The particles of  claim 3 , wherein the polymer derived ceramic material of the coating is pyrolized in a substantially non-oxydizing atmosphere such that a hard shell substantially encloses the core. 
     
     
         8 . The particles of  claim 7 , wherein the core comprises substantially no carbon particles. 
     
     
         9 . The particles of  claim 7 , wherein the core comprises carbon particles chemically or physically bonded to a ceramic matrix. 
     
     
         10 . The particles of  claim 9 , wherein the carbon particles are chemically bonded to the ceramic matrix. 
     
     
         11 . The particles of  claim 3 , wherein the coating is partially dried until tacky. 
     
     
         12 . The particles of  claim 3 , wherein an initial layer of the coating is pyrolized and a subsequent layer of the coating is added to the surface of the initial layer, wherein the subsequent layer is a liquid, slurry or tacky material. 
     
     
         13 . The particles of  claim 12 , wherein the subsequent layer is partially dried until tacky. 
     
     
         14 . The particles of  claim 1 , wherein the hydraulic diameter is 3 to 5 microns. 
     
     
         15 . The particles of  claim 1 , wherein particles are combined as building blocks for composite structures or beads made of a plurality of the particles. 
     
     
         16 . A method of forming a useful article from the particles of  claim 15 , comprising three dimensional printing of complex parts by depositing a plurality of the particles in a three dimensional pattern. 
     
     
         17 . A method of making a complex composite bead or rod comprising:
 combining a first material comprised of particles of a silica, a boron, a carbon, a carbide, a silicide, a sulfide, a boride, a silicate, a sulfate, a borate, a nitrate, a carbonate, or a mixture of these with a binder;   forming the first material into a particle core;   coating the particle core with a polymer derived ceramic material, forming a particle comprised of a shell around the particle core;   consolidating a plurality of particles having the shell around the particle cores, forming a discrete mass in the shape of a bead or a rod; and pyrolizing in a substantially non-oxidizing atmosphere, wherein the step of pyrolizing does not occur before the step of consolidating.   
     
     
         18 . (canceled) 
     
     
         19 . (canceled) 
     
     
         20 . The method of  claim 17 , wherein a step of drying occurs prior to the step of consolidating such that the shell becomes tacky.