Abstract: The invention relates to an apparatus and method for reducing contaminants from industrial processes. More particularly, the invention is directed to a method of sequestering pollutants from flue gases in operational plants. The method includes sequestering contaminants from a point source by reacting an alkaline material with a flue gas containing contaminants to be sequestered, wherein the reaction has a rapid mass transfer rate to sequester at least a portion of the contaminants.

Abstract: The present invention provides a process for preparing a precipitated calcium carbonate product. The process comprises the steps of preparing an aqueous suspension of precipitated calcium carbonate seeds by carbonating a suspension of Ca(OH)2 in the presence of 0.005 to 0.030 moles of Sr, in the form of Sr(OH)2, based upon moles of Ca(OH)2 prior to or during carbonation; forming an aqueous suspension of a precipitated calcium carbonate product by carbonating a slurry of Ca(OH)2 in the presence of 0.5 to 5% by dry weight of the precipitated calcium carbonate seeds, wherein the precipitated calcium carbonate seeds have a D50 that is less than the D50 of the precipitated calcium carbonate product and the precipitated calcium carbonate seeds have an aragonitic polymorph content greater than or equal to the precipitated calcium carbonate product.

Abstract: Stabilized, spherical, amorphous calcium carbonate particles having a mean particle diameter in the range from 0.05 ?m to 2.0 ?m and a water content of at most 5.0 wt % measured as residual moisture at 200° C., wherein the calcium carbonate particles comprise at least one substance which has a molar mass greater than 100 g/mol and satisfies the formula R—Xn, wherein the radical R represents a radical comprising at least one carbon atom, the radical X represents a group which comprises at least one oxygen atom and at least one carbon atom, sulphur atom, phosphorus atom and/or nitrogen atom and n preferably constitutes a whole number in the range from 1 to 20, the proportion of crystalline calcium carbonate is less than 30 wt %, and the specific surface area of the calcium carbonate particles is at most 20 m2/g.

Abstract: The present invention relates to a calcium carbonate having a surface charge, the preparing process thereof and filler for producing a paper using the same. The present invention provides the process of preparing a calcium carbonate having a surface charge, characterized in that it comprises the following steps of: preparing a solution mixture of one or more monomer selected from the group consisting of calcium hydroxide, acrylic acid, acrylamide, or [2-(acryloyloxy)ethyl]-trimethylammonium chloride; removing dissolved gases such as oxygen and carbon dioxide in the said solution by injecting nitrogen (N2) gas; adjusting pH of the said solution; and inducing a reaction by adding polymerization initiator of a high molecule while injecting carbon dioxide to the said mixture.

Abstract: Disclosed herein is a method of producing carbonate, comprising the steps of: providing a water-containing solution including cations that are precipitated in the form of a salt after undergoing a precipitation reaction with carbonate ions; and generating carbon dioxide microbubbles having a diameter of 50 ?m or less in the water-containing solution to induce the precipitation reaction between the cations and the carbonate ions. The method is advantageous in that the carbonate produced using the microbubble system disclosed in the method can be practically used as high-priced building materials, filler for paper manufacturing, etc. and can also be used in foods, medicines and the like depending on the purity thereof, so that it can be recovered in a high yield. Further, the method is advantageous in that carbon dioxide is consumed, and cations can be effectively removed from waste water, so that it is environmentally useful.

Abstract: A method of producing calcium carbonate from lime comprises the steps of: (i) providing an aqueous solution comprising 10% to 35% by weight of dissolved polyhydroxy compound and 1% to 5% by weight of dissolved calcium hydroxide (expressed as Ca(OH)2) and having a pH of at least 11.5; (ii) treating the solution prepared in step (i) to remove solids including suspended solids; (iii) dispersing carbon dioxide through the solution so as to form calcium carbonate with a consequential reduction in the pH of the reaction mixture, (iv) during a time period beginning at the start of a sudden, short rise in pH and ended during a subsequent fall in pH but before it reaches 9.5 terminating the dispersion of carbon dioxide and adding an alkaline reagent to maintain a pH for the product mixture of at least 9.5, and (v) recovering precipitated calcium carbonate.

Abstract: A method for obtaining particulate calcium carbonate exhibiting improved brightness and color and having uniformity of size such that when the particles are formed in the causticization process in a kraft pulp mill, the time required to separate the particles from liquors in which they are suspended is minimized and the amount of liquor recovered is maximized, with minimal dilution by water used for washing. The method includes the steps of a) slaking calcium oxide in water or an alkaline liquor containing as dissolved species predominantly sodium hydroxide; b) mixing the slaked lime with green liquor from a kraft pulping process to complete a causticization reaction that produces white liquor and lime mud; c) separating the lime mud from the white liquor; and d) milling a portion of the lime mud for use as a white mineral pigment in applications where such pigments are typically used.

Abstract: A process is disclosed for recycling carbon dioxide emissions from a fossil-fuel power plant into useful carbonated species The process primarily comprises the steps of: a) burning the fossil fuel, thereby generating heat and a hot exhaust gas containing CO2; and b) converting the heat into energy. The process is characterized in that it further comprises the steps of: c) cooling the exhaust gas; and d) biologically transforming the CO2 contained in the cooled exhaust gas into carbonated species, thereby obtaining a low CO2 exhaust gas and producing useful carbonated species. The low CO2 exhaust gas obtained in step d) can be released in the atmosphere without increasing the problem of greenhouse effect.

Abstract: A process for the separation of carbon dioxide from gas mixtures is disclosed in which a metal oxide sorbent, which is used to capture and release carbon dioxide, is recycled. The process incorporates the regeneration of the carbon dioxide capture capacity of the metal oxide to maintain a high capture capacity over many cycles. The regeneration involves hydrating the metal oxide and then heating the resulting metal hydroxide under a gas atmosphere that is effective to suppress the dehydration of the hydroxide so that dehydration occurs at an elevated temperature. The regeneration may also be used independently from the carbon dioxide separation process to produce, from a metal hydroxide, a metal oxide having an enhanced resistance to attrition and fragmentation.

Abstract: A fine powder of an alkaline earth metal carbonate selected from the group consisting of barium carbonate, strontium carbonate and calcium carbonate, in which a primary particle of the powder has a mean diameter of 30 to 90 nm, in which the mean diameter is measured on a circle obtained from a projected area of the primary particle, and in which an accumulated volume of micropores having a pore size in the range of 10 to 20 nm is not less than 5×10?2 cm3/g can be easily dispersed in an aqueous medium in the form of essentially primary particles by an industrially employable dispersing method.

Abstract: A process is disclosed for recycling carbon dioxide emissions from a fossil-fuel power plant into useful carbonated species The process primarily comprises the steps of: a) burning the fossil fuel, thereby generating heat and a hot exhaust gas containing CO2; and b) converting the heat into energy. The process is characterized in that it further comprises the steps of: c) cooling the exhaust gas; and d) biologically transforming the CO2 contained in the cooled exhaust gas into carbonated species, thereby obtaining a low CO2 exhaust gas and producing useful carbonated species. The low CO2 exhaust gas obtained in step d) can be released in the atmosphere without increasing the problem of greenhouse effect.

Abstract: The present invention relates to a method for production of calcium compounds having very low content of phosphorus and boron from an impure calcium chloride, solution containing phosphorus and boron, which method comprises the following steps: a) addition of a FeCl3-solution to the calcium chloride solution, b) adjusting the pH of the solution by addition of a base to between 3 and 9.5 for precipitation of iron hydroxide, iron phosphate and boron compounds, c) removal of the solid precipitate from the solution in step b) obtaining a purified calcium chloride solution, d) precipitation of a calcium compound from the solution from step c), and e) separation of the calcium compound from the solution in step d).

Abstract: The present invention provides a method and apparatus for sequestering carbon from atmospheric air using a hydroxide compound in a two stage process to maximize carbon dioxide capture. The first stage is provided by a coarse filter saturated with a calcium hydroxide solution. The second stage is provided by a reaction chamber having at least one spray nozzle for creating a mist of hydroxide solution within the reaction chamber. Air is drawn through the device by a fan to cause the air to first contact the hydroxide solution on the saturated filter, and then to contact the hydroxide solution in the mist sprayed within the reaction chamber. The hydroxide solution is collected in a reservoir, centrifuged to separate the captured carbon from the solution, and then recirculated back into the saturated filter and through the spray nozzles into the reaction chamber.

Abstract: Disclosed is a carbon dioxide gas processing apparatus including an oxidization vessel for producing a magnesium oxide by oxidizing magnesium-containing powder in an atmosphere of a gas such as a carbon dioxide gas that contains oxygen as a constituent element thereof, a carbonate production tank that reserves water or a water solution therein and that introduces the magnesium containing oxygen as a constituent element produced in the oxidization vessel, and a carbon dioxide gas supplying means for supplying carbon dioxide gas to the carbonate production tank.

Abstract: A method of producing calcium carbonate from lime comprises the steps of: (i) providing an aqueous solution comprising 10% to 35% by weight of dissolved polyhydroxy compound and 1% to 5% by weight of dissolved calcium hydroxide (expressed as Ca(OH)2) and having a pH of at least 11.5; (ii) treating the solution prepared in step (i) to remove solids including suspended solids; (iii) dispersing carbon dioxide through the solution so as to form calcium carbonate with a consequential reduction in the pH of the reaction mixture, (iv) during a time period beginning at the start of a sudden, short rise in pH and ended during a subsequent fall in pH but before it reaches 9.5 terminating the dispersion of carbon dioxide and adding an alkaline reagent to maintain a pH for the product mixture of at least 9.5, and (v) recovering precipitated calcium carbonate.

Abstract: Method for producing an aqueous suspension, which is based on a hydraulic binder, and a hardened binder product. According to the invention, a composition of blending agents is added in the aqueous phase into the binder, which composition comprises calcium carbonate particles having an average particle size of 2-200 nm, in order to generate an aqueous suspension and, if needed, mineral fillers are added into this suspension, in order to produce a hardening plaster or concrete mixture. Besides calcium carbonate, the composition of blending agents can comprise calcium hydrogen carbonate and meta-kaolin sinter, too.

Abstract: In a preferred embodiment, the invention relates to a process of sequestering carbon dioxide. The process comprises the steps of: (a) reacting a metal silicate with a caustic alkali-metal hydroxide to produce a hydroxide of the metal formerly contained in the silicate; (b) reacting carbon dioxide with at least one of a caustic alkali-metal hydroxide and an alkali-metal silicate to produce at least one of an alkali-metal carbonate and an alkali-metal bicarbonate; and (c) reacting the metal hydroxide product of step (a) with at least one of the alkali-metal carbonate and the alkali-metal bicarbonate produced in step (b) to produce a carbonate of the metal formerly contained in the metal silicate of step (a).

Abstract: A method of producing calcium carbonate. In the method a calcium oxide material is contacted in aqueous phase with carbon dioxide in a plurality of carbonation units. According to the invention, the calcium oxide material is carbonated in a first carbonation unit in an aqueous slurry at a pH in excess of 11.0 in order to produce a calcium carbonate into the aqueous slurry, from the first carbonation unit is withdrawn an effluent formed by an aqueous slurry containing calcium carbonate and calcium hydroxide, and the calcium hydroxide of the withdrawn effluent is then carbonated in a second carbonation unit to produce a calcium carbonate slurry having a pH of less than 6.9. The method allows for the production of both monodisperse particles with a narrow molecular weight distripution and multidisperse particles with a broad molecular weight distribution.

Abstract: A method and apparatus for producing a calcium carbonate product formed of small <100 ?m sized separate calcium carbonate particles. Calcium hydroxide is fed through a disintegration and spraying apparatus (14), operating on the principle of a pin mill, into a gas which contains carbon dioxide for precipitating calcium carbonate particles and which is inside a precipitation reactor (10). The temperature in the precipitation reactor is maintained at <65° C.

Abstract: A method to prevent build-up of limestone in a slaker that is used for batchwise slaking of burnt lime is described, in which lime slurry is produced with a greater degree of fineness and prolonged sedimentation time, where for immediate cleansing of the slaker before next slaking, after said calibration of the load cell aggregate, a number of valves are opened for given time periods for addition of flushing water to respective nozzles, in that flushing water is supplied sequentially via each valve to associated nozzle(s), until a predetermined amount of flushing water is reached in the slaker.

Abstract: Methods are provided for physically removing all the carbon dioxide from the combustion products of solid, liquid, and gaseous fossil fuels. The combustors operate without excess air to maximize the carbon dioxide at the exhaust, which is compressed with the nitrogen and mixed with pressurized water to dissolve the carbon dioxide in a chamber from which the nitrogen gas is removed. The solution is drained into a second lower pressure chamber from which the carbon dioxide re-evolves as a gas, which is then pressurized for sequestration in limestone formations as calcium bicarbonate. The water is recycled to repeat the separation process, and depressurization of the two gases recovers most of the compression energy.

Abstract: An aqueous dispersion includes a self-crosslinking alkylolacrylamide containing interpolymer, the interpolymer being prepared in an emulsion polymerization medium by way of interpolymerizing in the medium: (a) acrylamide monomer; (b) N—C2 to C10 alkylolacrylamide monomer, wherein the molar ratio of acrylamide:N—C2 to C10 alkylolacrylamide interpolymerized is at least 0.5; and (c) at least one or more additional ethylenically unsaturated monomers added to the medium in an amount of from about 80 weight % to about 98 weight % based on the dry weight of monomer interpolymerized in the medium. The dispersions are particularly useful as binders for fibrous webs.

Abstract: The present invention has an object to provide a method for producing particulate barium carbonate having desired properties such as high purity, fineness, and has a spherical shape. The present invention relates to a method of producing substantially spherical barium carbonate, including (A) mixing, in an aqueous medium, a barium compound with at least one first ingredient selected from the group consisting of gluconic acid or salts thereof, gluconolactone, glucoheptonic acid or salts thereof, and glucoheptonolactone, to prepare a mixture; and (B) reacting the barium compound with carbon dioxide or a water-soluble carbonate in the mixture, to produce substantially spherical barium carbonate.

Abstract: In a preferred embodiment, the invention relates to a process of sequestering carbon dioxide. The process comprises the steps of: (a) reacting a metal silicate with a caustic alkali-metal hydroxide to produce a hydroxide of the metal formerly contained in the silicate; (b) reacting carbon dioxide with at least one of a caustic alkali-metal hydroxide and an alkali-metal silicate to produce at least one of an alkali-metal carbonate and an alkali-metal bicarbonate; and (c) reacting the metal hydroxide product of step (a) with at least one of the alkali-metal carbonate and the alkali-metal bicarbonate produced in step (b) to produce a carbonate of the metal formerly contained in the metal silicate of step (a).

Abstract: A process is disclosed for recycling carbon dioxide emissions from a fossil-fuel power plant into useful carbonated species The process primarily comprises the steps of: a) burning the fossil fuel, thereby generating heat and a hot exhaust gas containing CO2; and b) converting the heat into energy. The process is characterized in that it further comprises the steps of: c) cooling the exhaust gas; and d) biologically transforming the CO2 contained in the cooled exhaust gas into carbonated species, thereby obtaining a low CO2 exhaust gas and producing useful carbonated species. The low CO2 exhaust gas obtained in step d) can be released in the atmosphere without increasing the problem of greenhouse effect.

Abstract: A process for converting carbon dioxide into solid material, which process comprises the steps of: (a) direct thermal activation of magnesium silicate hydroxide mineral feedstock by combustion of fuel to produce an activated feedstock; (b) separation from the activated feedstock of metal oxides at least substantially excluding magnesium oxide and magnesium silicate to produce a residual activated feedstock; (c) before or after said separation step suspension of the activated feedstock in a solvent to form a slurry; and (d) contacting the slurry of residual activated feedstock with carbon dioxide to convert the carbon dioxide into magnesium carbonate.

Abstract: Carbon dioxide containing gas is blown into a calcium hydroxide slurry having a calcium hydroxide concentration of 100 to 400 g/L obtained by wet slaking calcined lime with 4 N hydrochloric acid activity (value at 3 minutes) of 150 to 400 mL to allow them to react until the carbonation rate becomes 50 to 85%, then 1 to 20% by volume of the calcium hydroxide slurry is added, and carbon dioxide containing gas is further blown in to terminate the reaction. The calcium carbonate obtained by this method is precipitated calcium carbonate aggregates having a secondary particle diameter of 1 to 10 ?m and consisting of primary particles having a long diameter of 0.5 to 3.0 ?m, a short diameter of 0.1 to 1.0 ?m and an aspect ratio of 3 or more, has superior characteristics due to a BET specific surface area in the range of 8 to 20 m2/g and a pore volume in the range of 1.5 to 3.5 cm3/g, can be uniformly dispersed in pulp fiber, and thereby can be used to manufacture high bulk paper.

Abstract: When spherical calcium carbonate is produced by blowing a carbon dioxide gas or a carbon dioxide-containing gas into an aqueous suspension containing calcium hydroxide to react them, after start of the reaction, an aqueous solution or suspension of a water-soluble phosphoric acid compound or a water-soluble salt thereof is added to the reaction mixture when carbonation ratio reaches 2 to 10%, and the reaction is further allowed to continue at a low gas blowing rate of 1.0 NL/minute or lower (step (a)). Subsequently, an aqueous suspension containing calcium hydroxide and an aqueous solution or suspension of a water-soluble phosphoric acid compound or a water-soluble salt thereof are added to the reaction mixture, and a carbon dioxide gas or a carbon dioxide-containing gas is introduced to allow to react and thereby produce spherical calcium carbonate having a mean particle diameter of 10 ?m or larger.

Abstract: A method and apparatus for producing a calcium carbonate product formed of small <100 ?m sized separate calcium carbonate particles. Calcium hydroxide is fed through a disintegration and spraying apparatus (14), operating on the principle of a pin mill, into a gas which contains carbon dioxide for precipitating calcium carbonate particles and which is inside a precipitation reactor (10). The temperature in the precipitation reactor is maintained at <65° C.

Abstract: A method of sequestering a multi-element gas emitted by an industrial plant is described herein, the method comprising: contacting a solution, including a first reactant comprising a multi-element gas emitted by an industrial plant and at least one gas absorber comprising nitrogen, for example ammonia or an amine, with a solid, including a second reactant, under conditions that promote a reaction between the first reactant and the second reactant to provide a first product, which incorporates one or more elements of the multi-element gas, thereby sequestering the multi-element gas.

Abstract: Process to prepare a precipitated calcium carbonate (PCC) comprising the following steps: (i) providing CaO, which is optionally partially or fully slaked (hereafter “calcium source”); ({umlaut over (?)}) providing a CO2-comprising gas; ({umlaut over (?)}) contacting said calcium source of step (i) and said CO2-comprising gas of step (ii) in an aqueous environment in a reactor, in one or more steps; (iv) obtaining a PCC-comprising suspension; (v) optionally concentrating said PCC-comprising suspension of step (iv); (vi) optionally adding dispersing additives to the suspension of step (iv) and/or (v); (vii) optionally grinding the product of step iv, v or vi.

Abstract: The invention consists in the use, in a method to manufacture a mineral matter, notably a precipitated calcium carbonate, of a polymer consisting of at least one vinylic monomer chosen from among acrylic or methacrylic acid, acrylamide, methacrylamide or a cationic monomer, or their blends, and at least one non-ionic monomer. The use of this polymer enables the carbonation time of the PCC to be reduced, without however impairing its crystallographic structure and its granulometric characteristics.

Abstract: The present invention describes methods and systems for extracting, capturing, reducing, storing, sequestering, or disposing of carbon dioxide (CO2), particularly from the air. The CO2 extraction methods and systems involve the use of chemical processes, mineral sequestration, and solid and liquid sorbents. Methods are also described for extracting and/or capturing CO2 via condensation on solid surfaces at low temperature.

Abstract: A method and an apparatus for controlling a causticizing process, the process comprising slaking, causticizing and white liquor preparation. The slaking is carried out using a slaker into which green liquor and lime is fed to produce lime milk. The causticizing process is controlled by applying a model that describes at least a part of the causticizing process.

Abstract: A method for making a white synthetic carbide lime filler composition of calcium hydroxide and calcium carbonate, wherein the calcium carbonate is in the form of surface carbonation on the calcium hydroxide. The method can include calcining calcium carbonate, hydrating the calcined material under controlled conditions which maintain a low moisture content and fracture the hydrated material into small particles of calcium hydroxide, carbonating the small calcium hydroxide particles to create the surface carbonation of calcium carbonate, and classifying the carbonated synthetic carbide lime particles to separate off oversized particles. The method can use a combined classifying and carbonating process, and a modified classifying vessel can be provided to carry out the combined process.

Abstract: A fluidized bed reactor device for sequestering flue gas CO2 from a flue gas source is provided. The fluidized bed reactor device comprises an operating portion having a first end and a second end. A flue gas inlet is formed at the first end of the operating portion with the flue gas inlet receiving flue gas from the flue gas source. A flue gas outlet formed at the second end of the operating portion. A distributor plate is mounted within the operating portion adjacent the first end of the operating portion. A volume of fly ash is encased within the operating portion between the second end and the distributor plate with the flue gas traveling through the distributor plate and the fly ash creating reacted flue gas wherein the reacted flue gas exits the operating portion through the flue gas outlet.

Abstract: The present invention relates to a kaolin composition having improved physical properties, for example, for use in the production of paper products. The composition can comprise kaolin having a shape factor of at least about 20. The kaolin can have a particle size distribution such that at least about 94% by weight of the kaolin can have an esd of less than about 2 ?m and/or at least about 80% by weight of the kaolin can have an esd of less than 1 ?m. The amount of the kaolin having an esd of less than about 0.25 ?m can range from about 25% to about 60% by weight. The Hercules viscosity of the kaolin product is less than 4000 rpm at 18 dynes at 63% solids and less than 1500 rpm at 18 dynes at 69% solids when measured using the “A” bob. The present invention also relates to an improved method for making the kaolin product from sedimentary kaolin.

Abstract: When spherical calcium carbonate is produced by blowing a carbon dioxide gas or a carbon dioxide-containing gas into an aqueous suspension containing calcium hydroxide to react them, after start of the reaction, an aqueous solution or suspension of a water-soluble phosphoric acid compound or a water-soluble salt thereof is added to the reaction mixture when carbonation ratio reaches 2 to 10%, and the reaction is further allowed to continue at a low gas blowing rate of 1.0 NL/minute or lower (step (a)). Subsequently, an aqueous suspension containing calcium hydroxide and an aqueous solution or suspension of a water-soluble phosphoric acid compound or a water-soluble salt thereof are added to the reaction mixture, and a carbon dioxide gas or a carbon dioxide-containing gas is introduced to allow to react and thereby produce spherical calcium carbonate having a mean particle diameter of 10 ?m or larger.

Abstract: Methods are provided for producing a composition comprising carbonates, wherein the methods comprise utilizing waste sources of metal oxides. An aqueous solution of divalent cations, some or all of which are derived from a waste source of metal oxides, may be contacted with CO2 and subjected to precipitation conditions to provide compositions comprising carbonates. In some embodiments, a combustion ash is the waste source of metal oxides for the aqueous solution containing divalent cations. In some embodiments, a combustion ash is used to provide a source of proton-removing agents, divalent cations, silica, metal oxides, or other desired constituents or a combination thereof.

Abstract: When spherical calcium carbonate is produced by blowing a carbon dioxide gas or a carbon dioxide-containing gas into an aqueous suspension containing calcium hydroxide to react them, after start of the reaction, an aqueous solution or suspension of a water-soluble phosphoric acid compound or a water-soluble salt thereof is added to the reaction mixture when carbonation ratio reaches 2 to 10%, and the reaction is further allowed to continue at a low gas blowing rate of 1.0 NL/minute or lower (step (a)). Subsequently, an aqueous suspension containing calcium hydroxide and an aqueous solution or suspension of a water-soluble phosphoric acid compound or a water-soluble salt thereof are added to the reaction mixture, and a carbon dioxide gas or a carbon dioxide-containing gas is introduced to allow to react and thereby produce spherical calcium carbonate having a mean particle diameter of 10 ?m or larger.

Abstract: A process for sequestration of carbon dioxide comprising the following steps: (a) dispersing solid waste material comprising calcium oxide and a calcium-comprising mixed oxide in water to dissolve at least part of the calcium oxide and to form calcium oxide-depleted solid waste material in a calcium hydroxide solution; (b) separating the calcium hydroxide solution from the calcium oxide-depleted solid waste material; (c) converting the calcium hydroxide in the separated calcium hydroxide solution in precipitated calcium carbonate; and (d) contacting an aqueous slurry of the calcium oxide-depleted solid waste material with carbon dioxide for mineral carbonation of the carbon dioxide to form carbonated solid waste material.

Abstract: The present invention relates to a process of preparing precipitated calcium carbonate (PCC) in a low energy intensity reactor in such a manner that the amount of solids in the PCC product can be raised to 35% or more without performing a dewatering step. The process comprises performing in parallel and in two or more separate reaction vessel the steps of contacting calcium hydroxide with a gas comprising carbon dioxide to allow formation of calcium carbonate, and adding calcium oxide, lime or dry calcium hydroxide or a combination of any of the three to a part of the resulting mixture of calcium hydroxide and calcium carbonate. The invention further provides a specialized reactor system as well as the use of this reactor system in the manufacture of PCC.

Abstract: Apparatuses and methods for removing carbon dioxide and other pollutants from a gas stream are provided. The methods include obtaining hydroxide in an aqueous mixture, and mixing the hydroxide with the gas stream to produce carbonate and/or bicarbonate. Some of the apparatuses of the present invention comprise an electrolysis chamber for providing hydroxide and mixing equipment for mixing the hydroxide with a gas stream including carbon dioxide to form an admixture including carbonate and/or bicarbonate.

Abstract: The invention provides a process for sequestration of carbon dioxide by mineral carbonation comprising the following steps: (a) converting a magnesium or calcium sheet silicate hydroxide into a magnesium or calcium ortho- or chain silicate by bringing the silicate hydroxide in direct or indirect heat-exchange contact with hot synthesis gas to obtain the silicate, silica, water and cooled synthesis gas; (b) contacting the silicate obtained in step (a) with carbon dioxide to convert the silicate into magnesium or calcium carbonate and silica.

Abstract: Process for the production of precipitated calcium carbonate particles, structured at the nanoscale, by carbonation of milk of lime in the presence of a crystallization controller selected from the following list: polyaspartic acid, dioctyl sodium sulphosuccinate, polyacrylic acid, the molecular weight of which is between 500 and 15 000, and citric acid. When the crystallization controller is citric acid, its concentration in the milk of lime is between 5 and 15%.

Abstract: The invention provides methods and apparatuses for removing carbon dioxide from a gas stream. In particular, the invention provides methods and apparatuses for absorbing carbon dioxide from a coal-fired boiler flue gas stream using an absorbing solution and for regeneration of an alkaline component used in the absorbing solution. In one embodiment, the invention provides a method for removing carbon dioxide from a gas stream by contacting a gas stream containing carbon dioxide with an alkaline liquid stream; absorbing at least a portion of the carbon dioxide into the alkaline liquid stream to produce absorbed carbon dioxide; and catalyzing a reaction of the absorbed carbon dioxide to a form of carbonate.

Abstract: Method for industrial manufacture of pure MgCO3 comprising providing an olivine containing species of rock, to comminute the olivine containing species of rock to increase its surface, to contact the comminuted olivine containing species of rock with water and CO2. The process is conducted in at least two steps, namely a first step (R1) at a first pH where a dissolving reacting as represented the equation: Mg2SiO4(S)+4H+=2Mg2++SiO2(aq)+2H2O, takes place. Then a precipitation takes place in the second step (R2) at a higher pH as represented by the equations: Mg2++HCO3?=MgCO3(S)+H+, and Mg2++CO32?=MgCO3(S), the presence of HCO3? and H+ ions mainly provided by the reaction between CO2 and water.

Abstract: The light calcium carbonate in the form of microparticle aggregate of the present invention has a BET specific surface area not smaller than 10 m2/g and not larger than 25 m2/g, a pore volume of 0.05 cm3/g or larger for pores having a pore diameter of 0 to 1000 ? as determined by the nitrogen adsorption method, and a pore volume ratio of 25% or more for pores having a pore diameter of 250 ? or smaller based on the total pore volume as determined by the nitrogen adsorption method, and shows an oil absorption of 100 cc/100 g or more as determined by using liquid paraffin. By using this light calcium carbonate as a filler of printing paper, superior ink absorbing property and opacity (especially opacity after printing) can be imparted to the printing paper.

Abstract: The disclosure provides methods and systems for sequestering and/or reducing carbon dioxide present in an industrial effluent fluid stream containing carbon dioxide. A scrubbing material comprising a first component, a second component (distinct from the first component), and preferably water, is contacted with the effluent fluid stream. The first component comprises a source of calcium oxide and a source of alkali metal ions. The second component comprises a slag having one or more reactive silicate compounds. Methods of reducing carbon dioxide from exhaust generated by combustion sources, lime and/or cement kilns, iron and/or steel furnaces, and the like are provided. Carbon dioxide emission abatement systems are also disclosed. Methods of recycling industrial byproducts are further provided.

Abstract: A fine alkaline earth metal carbonate powder showing high dispersibility, in which the alkaline earth metal carbonate is selected from the group consisting of strontium carbonate and barium carbonate, can be prepared by a process comprising the steps of pulverizing a powder of strontium carbonate or barium carbonate in an aqueous medium using ceramic beads having a mean diameter of 10 to 1,000 ?m in the presence of a polymer comprising a polycarboxylic acid or anhydride thereof having a side chain of a polyoxyalkylene group, and drying the pulverized powder.