Precursor compositions for ceramic proppants

Abstract

A precursor composition for the production of granulated ceramic material to be used as hydraulic fracture proppant, comprises 20 to 55% pyroxene, and 15 to 50% olivine. The remaining component is quartz and/or feldspar. The precursor composition can be sintered in a broader temperature range. The resulting proppant material shows high mechanical strength and resistance to acids, and also higher stability under hydrothermal conditions than the prior art.

1 . A precursor composition for the production of granulated ceramic material, particularly for ceramic proppants, 
 comprising 20 to 55% by weight of pyroxene, and 15 to 50% by weight of olivine; the remaining component up to 100% being quartz and/or feldspar.    
     
     
         2 . The precursor composition according to  claim 1 , characterised in that 
 the composition comprises 20 to 45% by weight of pyroxene, and 20 to 45% by weight of olivine.    
     
     
         3 . The precursor composition according to  claim 1 , characterized in that 
 the composition comprises 0 to 8% by weight of FeO+Fe 2 O 3 , 0 to 8% by weight of Al 2 O 3 , 0 to 1.2% by weight of K 2 O, 0 to 1.5% by weight of Na 2 O, 0 to 0.9% by weight of TiO 2 , and 0 to 0.6% by weight of P 2 O 5 .    
     
     
         4 . The precursor composition according to  claim 1 , characterised in that 
 the composition comprises, in percent by weight: 
 20-28% MgO;  
 50-65% SiO 2 ;  
 4-8% FeO+Fe 2 O 3 ;  
 3-8% Al 2 O 3 ;  
 0.4-3.0% CaO;  
 0.3-1.2% K 2 O;  
 0.3-1.5% Na 2 O;  
 0.1-0.9% TiO 2 ; and  
 0.1-0.6% P 2 O 5 .  
   
     
     
         5 . A method for the production of granulated ceramic material, particularly for ceramic proppants, comprising the steps of: 
 preparing a precursor composition according to  claim 1 , by grinding a corresponding mixture of raw materials to an average particle size between 2 and 3 μm;    pelletizing the precursor composition to pellets with a size between 1.2 and 1.8 mm; and    sintering the precursor pellets at a temperature between 1150 and 1280° C.    
     
     
         6 . The method according to  claim 5 , characterized in that the sintering process is carried out in a revolving kiln.  
     
     
         7 . A granulated ceramic material produced with a method according to  claim 5 .  
     
     
         8 . The use of a precursor composition according to  claim 1  for the production of granulated ceramic material, particularly hydraulic fracturing proppants.  
     
     
         9 . The use of a granulated ceramic material according to  claim 7  as a hydraulic fracturing proppant.  
     
     
         10 . The precursor composition according to  claim 2 , characterized in that 
 the composition comprises 0 to 8% by weight of FeO+Fe2O3, 0 to 8% by weight of Al2O3, 0 to 1.2% by weight of K2O, 0 to 1.5% by weight of Na2O, 0 to 0.9% by weight of TiO2, and 0 to 0.6% by weight of P2O5;    the composition comprises, in percent by weight: 
 20-28% MgO;  
 50-65% SiO2;  
 4-8% FeO+Fe2O3;  
 3-8% Al2O3;  
 0.4-3.0% CaO;  
 0.3-1.2% K2O;  
 0.3-1.5% Na2O;  
 0.1-0.9% TiO2; and  
 0.1-0.6% P2O5.  
   
     
     
         11 . A method for the production of granulated ceramic material, particularly for ceramic proppants, comprising the steps of: 
 preparing a precursor composition according to  claim 10 , by grinding a corresponding mixture of raw materials to an average particle size between 2 and 3 μm;    pelletizing the precursor composition to pellets with a size between 1.2 and 1.8 mm; and    sintering the precursor pellets at a temperature between 1150 and 1280° C.    
     
     
         12 . The method according to  claim 11 , characterized in that the sintering process is carried out in a revolving kiln.  
     
     
         13 . A granulated ceramic material produced with a method according to  claim 12 .  
     
     
         14 . The use of a precursor composition according to  claim 10  for the production of granulated ceramic material, particularly hydraulic fracturing proppants.  
     
     
         15 . The use of a granulated ceramic material according to  claim 14  as a hydraulic fracturing proppant.