Process to make calcium oxide or ordinary portland cement from calcium bearing rocks and minerals

Abstract

Aspects of the invention include a method of producing a cement material comprising step of: first reacting a calcium-bearing starting material with a first acid to produce an aqueous first calcium salt; second reacting the aqueous first calcium salt with a second acid to produce a solid second calcium salt; wherein the second acid is different from the first acid and the second calcium salt is different from the first calcium salt; and thermally treating the second calcium salt to produce a first cement material. Preferably, but not necessarily, during the second reacting step, reaction between the first calcium salt and the second acid regenerates the first acid.

1 . A method of producing a cement material, the method comprising steps of:
 first reacting a calcium-bearing starting material with a first acid to produce an aqueous first calcium salt;   second reacting the aqueous first calcium salt with a second acid to produce a solid second calcium salt; wherein the second acid is different from the first acid and the second calcium salt is different from the first calcium salt; and   thermally treating one or more calcium salts to produce a first cement material.   
     
     
         2 . The method of  claim 1 , wherein the one or more calcium salts comprises the second calcium salt. 
     
     
         3 . The method of  claim 1 , wherein, during the second reacting step, reaction between the first calcium salt and the second acid regenerates the first acid. 
     
     
         4 - 5 . (canceled) 
     
     
         6 . The method of  claim 1  comprising a first separating step after the first reacting step and before the second reacting step; the first separating step comprising separating a first aqueous fraction from a first solid fraction; wherein the first aqueous fraction comprises the aqueous first calcium salt and the first solid fraction comprises one or more solid byproducts formed during the first reacting step. 
     
     
         7 - 8 . (canceled) 
     
     
         9 . The method of  claim 1  comprising a second acid regeneration step; wherein the second acid regeneration step comprises converting one or more gas products of the thermally treating step to the second acid. 
     
     
         10 - 14 . (canceled) 
     
     
         15 . The method of  claim 1 , wherein, during the second reacting step, reaction between the first calcium salt and the second acid regenerates the first acid according to formula FX3:
   CaCl 2(aq) +H 2 SO 4 ->CaSO 4(s) +2HCl  (FX3); wherein:
   the first calcium salt is CaCl 2 );   the first acid is HCl;   the second acid is H 2 SO 4 ; and   the second calcium salt is CaSO 4 .   
     
     
         16 . The method of  claim 1 , wherein the calcium-bearing starting material has at least 1 dry wt. % of Ca. 
     
     
         17 - 18 . (canceled) 
     
     
         19 . The method of  claim 1 , wherein the calcium-bearing starting material comprises at least one natural rock or mineral; wherein the at least one natural rock or mineral comprises basalt, igneous appetites, wollastonite, anorthosite, montmorillonite, bentonite, calcium-containing feldspar, anorthite, diopside, pyroxene, pyroxenite, mafurite, kamafurite, clinopyroxene, colemonite, grossular, augite, pigeonite, margarite, calcium serpentine, garnet, scheilite, skarn, limestone, natural gypsum, appetite, fluorapatite, or any combination of these. 
     
     
         20 - 21 . (canceled) 
     
     
         22 . The method of  claim 1 , wherein calcium-bearing starting material comprises cement, concrete, Portland cement, fly ash, slag, or any combination of these. 
     
     
         23 . The method of  claim 1 , wherein the first acid is hydrochloric acid and the aqueous first calcium salt is calcium chloride. 
     
     
         24 . The method of  claim 1 , wherein the second acid is sulfuric acid and/or sulfurous acid. 
     
     
         25 . The method of  claim 1 , wherein the aqueous first calcium salt is calcium chloride and the solid second calcium salt is calcium sulfate and/or calcium sulfite. 
     
     
         26 - 28 . (canceled) 
     
     
         29 . The method of  claim 1 , wherein the first reacting step comprises reacting the calcium-bearing starting material with hydrochloric acid to form at least aqueous calcium chloride, aqueous aluminum chloride, and solid silica. 
     
     
         30 - 32 . (canceled) 
     
     
         33 . The method of  claim 1  comprising a step of forming a composite cement material; wherein: (i) the thermally treating step comprises the step of forming the composite cement material and the first cement material is the composite cement material or (ii) the step of forming the composite material is performed using the first cement material formed during the thermally treating step. 
     
     
         34 - 36 . (canceled) 
     
     
         37 . The method of  claim 33 , wherein the composite cement material is ordinary Portland cement or a Portland cement clinker, and/or the first cement material is calcium oxide. 
     
     
         38 - 41 . (canceled) 
     
     
         42 . The method of  claim 1  comprising forming and isolating silica-fume grade silica, nano-silica, and/or micro-silica from the calcium-bearing starting material. 
     
     
         43 . The method of  claim 1  comprising forming and isolating alumina from the calcium-bearing starting material. 
     
     
         44 - 47 . (canceled) 
     
     
         48 . The method of  claim 1  comprising forming and isolating iron oxide from the calcium-bearing starting material. 
     
     
         49 . The method of  claim 48 , wherein the step of forming and isolating the iron oxide comprises:
 forming an aqueous solution having aqueous iron sulfate and/or iron chloride and magnesium sulfate salt and/or chloride salt formed as byproducts during the second reacting step; wherein the aqueous solution is free of a calcium salt; and   using SO 2  to precipitate MgSO 3 .   
     
     
         50 - 69 . (canceled) 
     
     
         70 . A method for producing a cement material via reductive thermal decomposition, the method comprising steps of:
 reacting a calcium-bearing material with a chemically reducing gas to produce methane and a cement material.   
     
     
         71 - 82 . (canceled) 
     
     
         83 . A method of producing a cement material, the method comprising steps of:
 first reacting a calcium-bearing starting material with a first acid to produce a first aqueous fraction comprising an aqueous first calcium salt and a first solid fraction comprising one or more solid byproducts; wherein:
 the calcium-bearing starting material has a chemical composition comprising a plurality of metal elements including at least Ca and Si; 
 the one or more solid byproducts comprises a silicon salt; 
   first separating the first aqueous fraction from the first solid fraction; and   treating the first calcium salt to produce a first cement material.   
     
     
         84 - 95 . (canceled) 
     
     
         96 . The method of  claim 1 , wherein the first reacting step comprises reacting the calcium-bearing starting material with hydrochloric acid to form at least aqueous calcium chloride, aqueous aluminum chloride, aqueous iron chloride, aqueous magnesium chloride, and solid silica. 
     
     
         97 . (canceled) 
     
     
         98 . The method of  claim 96 , wherein the second reacting step comprises reacting at least the aqueous calcium chloride, and sulfuric acid to form at least solid calcium sulfate, solid calcium sulfate, and hydrochloric acid. 
     
     
         99 . (canceled) 
     
     
         100 . The method of  claim 1 , comprising forming and isolating aluminum chloride and forming aluminum metal via electrowinning the aluminum chloride. 
     
     
         101 . (canceled) 
     
     
         102 . The method of  claim 1 , comprising forming and isolating iron sulfate and forming iron metal via electrowinning the iron sulfate. 
     
     
         103 . (canceled)