Dust free inorganic particles and method of making same

Abstract

A long term dust free mass of free flowing inorganic particles of the type creating airborne silica dust, preferably sand particles as used for hydraulic fracturing, where the particles are coated with a dust suppression solution having 0.10 to 6.0 percent by weight a soluble polymer and an added, small amount of a surfactant, which small amount is less than 0.5 and preferably less than 0.10 percent by weight of the solution. The mass has a very low dosage of the solution, in the range of 0.1 to 10 milliliters per pound of the mass, so the mass has a moisture content of less than 0.30 percent by weight.

1 - 30 . (canceled) 
     
     
         31 . A long term dust free mass of inorganic particles formed from a mineral of the type creating airborne silica dust, said particles having surfaces spray coated at ambient temperature by an air mist with a dust suppression solution of water soluble polymer which is attached to and spread over said surfaces of said particles, said dust suppression solution of water soluble polymer comprising a small amount of surfactant constituting less than 0.5 percent by weight of said solution, wherein the amount of solution added to said mass is a selected amount in the range of 0.01 to 10 mL/lbs., said selected amount resulting in a moisture content of said mass of less than 0.30 percent by weight so said long term dust free mass is also free flowing. 
     
     
         32 . A long term dust free mass as defined in  claim 31  wherein said selected amount is at least 0.8 mL/lbs. 
     
     
         33 . A long term dust free mass as defined in  claim 31  wherein said inorganic particles are sand particles. 
     
     
         34 . A long term dust free mass as defined in  claim 31  wherein said mass of inorganic particles is a proppant for hydraulic fracturing. 
     
     
         35 . A long term dust free mass as defined in  claim 31  wherein said dust suppression polymer solution is at least 97 percent by weight water. 
     
     
         36 . A dust free mass of sand particles where said mass includes particles coated by a dust suppression polymer solution of water soluble polymer and having at least 90 percent by weight water and an added, small amount of surfactant, said small amount is less than 0.5 percent by weight of said solution and said mass having a very low dosage of said polymer solution so said mass has a moisture content of less than 0.30 percent by weight. 
     
     
         37 . A dust free mass as defined in  claim 36  wherein said very low dosage is in the range of 0.01 to 10 mL/lbs. 
     
     
         38 . A dust free mass as defined in  claim 37  wherein said very low dosage is at least 0.8 mL/lbs. 
     
     
         39 . A dust free mass as defined in  claim 36  wherein said polymer solution contains at least two polymers. 
     
     
         40 . A dust free mass as defined in  claim 36  wherein said small amount of surfactant is less than 0.10 percent by weight of said solution. 
     
     
         41 . A dust free mass as defined in  claim 36  wherein said small amount of surfactant is less than 0.05 percent by weight of said solution. 
     
     
         42 . A dust free mass as defined in  claim 36  wherein said mass of sand particles is a proppant for hydraulic fracturing. 
     
     
         43 . A method of producing a long term dust free mass of sand particles, which mass has an average dust concentration of less than 0.05 milligrams per cubic meter for at least 4 days, said method comprising coating said particles with a dust suppression solution of water soluble polymer having a small amount of surfactant of less than 0.50 percent by weight with a very low dosage of said solution in said mass so said mass has a moisture content of less than 0.30 percent by weight. 
     
     
         44 . A method as defined in  claim 43  wherein said very low dosage of said polymer solution in said mass is in the range of 0.80 to 10 mL/lbs. 
     
     
         45 . A method as defined in  claim 43  wherein said small amount of surfactant is less than 0.10 percent. 
     
     
         46 . A method as defined in  claim 43  wherein said polymer solution is sprayed onto said inorganic particles. 
     
     
         47 . A method as defined in  claim 46  wherein the spraying operation is by a forced air mist to spread said polymer solution over the surfaces of said particles. 
     
     
         48 . A method as defined in  claim 43  wherein a selected amount of said solution is mixed with a selected amount of said sand particles at a temperature less than 60° C. 
     
     
         49 . A method as defined in  claim 43  wherein said mass of sand particles is a proppant for hydraulic fracturing. 
     
     
         50 . A mass of inorganic particles formed from a mineral of the type creating airborne silica dust, said particles having surfaces coated with a dust suppression solution of water soluble polymer, which solution is attached to and spread over said surfaces, said solution having only a small amount of a surfactant, said small amount being less than 0.5 percent of water soluble polymer and where the amount of solution added to said mass is an amount resulting in a moisture content of said mass is less than 0.30 percent so said mass is dust free and free flowing. 
     
     
         51 . A mass as defined in  claim 50  said small amount of surfactant is less than 0.10 percent. 
     
     
         52 . A mass of inorganic particles as defined in  claim 50  wherein said mineral is sand. 
     
     
         53 . A mass of inorganic particles as defined in  claim 50  wherein said mass is a proppant used for hydraulic fracturing. 
     
     
         54 . A mass of inorganic particles as defined in  claim 50  wherein said water soluble polymer includes at least two different polymers.