A method of manufacture of high-solids hydroxide slurries from caustic calcined carbonate powder is described, whereby the properties of the slurry are its low resistance to shear thinning to facilitate transport, a high stability for transport and storage, ease of reconstitution after long periods of storage, and, as required, a high concentration of chemically reactive species at the particle surface. The method achieves these specifications by mixing caustic calcined carbonate or hydroxide powder with water in an insulated reactor vessel, and agitating the slurry sufficiently such that the hydration reaction causes the water to spontaneously boil, such that the remaining hydration proceeds spontaneously under the fixed conditions of boiling through the water loss. The mixing process is preferably carried out by a shear pump. A viscosity modifier, such as acetic acid, is used to thin the slurry to enable the mixing system to maintain uniform mixing. The reaction is terminated when the boiling has spontaneously ceased and the temperature has spontaneously dropped to a set point though the reactor heat losses, where the processing time is sufficiently long that the slurry meets the desired specifications.

A method of manufacture of high-solids hydroxide slurries from caustic calcined carbonate powder is described, whereby the properties of the slurry are its low resistance to shear thinning to facilitate transport, a high stability for transport and storage, ease of reconstitution after long periods of storage, and, as required, a high concentration of chemically reactive species at the particle surface. The method achieves these specifications by mixing caustic calcined carbonate or hydroxide powder with water in an insulated reactor vessel, and agitating the slurry sufficiently such that the hydration reaction causes the water to spontaneously boil, such that the remaining hydration proceeds spontaneously under the fixed conditions of boiling through the water loss. The mixing process is preferably carried out by a shear pump. A viscosity modifier, such as acetic acid, is used to thin the slurry to enable the mixing system to maintain uniform mixing. The reaction is terminated when the boiling has spontaneously ceased and the temperature has spontaneously dropped to a set point though the reactor heat losses, where the processing time is sufficiently long that the slurry meets the desired specifications.

Provided herein are zero carbon dioxide (CO.sub.2) emission processes and systems to carry out the processes, comprising a) calcining limestone in a cement plant in an electric kiln to form a mixture comprising calcium oxide and a first gaseous stream comprising clean carbon dioxide, wherein the clean carbon dioxide comprises no gaseous or non-gaseous components from combustion of fuel; b) treating the mixture comprising calcium oxide with a N-containing salt solution under one or more dissolution conditions to produce a first aqueous solution comprising calcium salt; and c) contacting the first aqueous solution with the first gaseous stream comprising clean carbon dioxide under one or more precipitation conditions to produce a precipitation material comprising vaterite, aragonite, calcite, or combinations thereof.

A method is shown for forming a high solids reactive lime slurry from quicklime. The timely addition of a carbohydrate and antiscalant polymer to slaking water provides desirable degree of control over the rate of reaction in which the heat of reaction is moderated to ensure the antiscalant polymer remains intact, thereby producing a fine quicklime slurry with low and stable viscosity.

A method is shown for forming a high solids reactive lime slurry from quicklime. The timely addition of a carbohydrate and antiscalant polymer to slaking water provides desirable degree of control over the rate of reaction in which the heat of reaction is moderated to ensure the antiscalant polymer remains intact, thereby producing a fine quicklime slurry with low and stable viscosity.

Methods and systems for making calcium oxide (CaO), carbon dioxide (CO.sub.2) and/or calcium hydroxide (Ca(OH).sub.2) from aragonite, for example, oolitic aragonite, are provided. The method can include applying solar energy, for example, by focusing one or more mirrors in one or more heliostats, to heat a reactant mixture in a vessel. The reactant mixture includes oolitic aragonite and can be heated to a temperature from 500° C. to 950° C. The system can include a vessel and a means for applying solar energy to heat a supply of oolitic aragonite disposed inside the vessel. Methods of converting the CO.sub.2 to ethanol, ethylene, graphene, and/or methane are also provided.

Methods and systems for making calcium oxide (CaO), carbon dioxide (CO.sub.2) and/or calcium hydroxide (Ca(OH).sub.2) from aragonite, for example, oolitic aragonite, are provided. The method can include applying solar energy, for example, by focusing one or more mirrors in one or more heliostats, to heat a reactant mixture in a vessel. The reactant mixture includes oolitic aragonite and can be heated to a temperature from 500° C. to 950° C. The system can include a vessel and a means for applying solar energy to heat a supply of oolitic aragonite disposed inside the vessel. Methods of converting the CO.sub.2 to ethanol, ethylene, graphene, and/or methane are also provided.

A fine grit classifier for removing grit from a milk of lime slurry includes a settling tank for receiving the milk of lime slurry, means for creating turbulence inside the tank to promote grit settling, a launder for collecting milk of lime slurry from an upper portion of the settling tank and directing milk of lime slurry to an outlet, and an auger for transporting settled grit from the lower portion of the settling tank and discharging the settled grit.

A composition of milk of lime comprising particles of slaked lime suspended in an aqueous phase, characterised in that said particles of slaked lime have a particle size described by a particle size distribution profile that is narrow and monomodal and the method of production thereof.

Calcium hydroxide-containing compositions can be manufactured by slaking quicklime, and subsequently drying and milling the slaked product. The resulting calcium hydroxide-containing composition can have a size, steepness, pore volume, and/or other features that render the compositions suitable for treatment of exhaust gases and/or removal of contaminants. In some embodiments, the calcium hydroxide-containing compositions can include a D.sub.10 from about 0.5 microns to about 4 microns, a D.sub.90 less than about 30 microns, and a ratio of D.sub.90 to D.sub.10 less than 20, wherein individual particles include a surface area greater than or equal to about 25 m.sup.2/g.