Abstract: Provided herein are integrated biomass combustion-carbonation gas conditioning systems to directly sequester carbon dioxide from biomass-derived CO2-containing flue gas. The CO2 is sequestered by mineral carbonation in concrete materials within a carbonation reactor. The mineral carbonation processes sequester CO2 in concrete materials, aqueous slurries, or aggregates without any additional carbon enrichment process. Contacting a CO2-containing gas stream from a biomass combustion apparatus with concrete, aggregate, or alkaline solutions, causes a carbonation reaction in which carbonation products such as calcium carbonate (CaCO3) and alumina silica gel are formed. The carbonation reactions set forth herein are useful for strengthening concrete and concrete components. Certain processes herein condition the biomass-derived flue gas. The conditioning includes condensing the gas to remove acidic gas, and to remove particulates and water.

Abstract: Various embodiments include a system or platform that uses electrochemistry to upcycle waste products and low-value minerals into valuable, carbon dioxide (CO2)-neutral materials. Various embodiments may include systems and/or methods for processing material inputs using an electrochemical reactor. Various embodiments may include systems, methods, and/or devices for capturing and sequestering carbon dioxide (CO2) while producing valuable co-products.

Abstract: Techniques for growing crystalline calcium carbonate solids such that the crystalline calcium carbonate solids include a volume of 0.0005 mm3 to 5 mm3, include a slaker to react quicklime (CaO) and a low carbonate content fluid to yield a slurry of primarily slaked lime (Ca(OH)2); a fluidized-bed reactive crystallizer that encloses a solid bed mass and includes an input for a slurry of primarily slaked lime, an input for an alkaline solution and carbonate, and an output for crystalline calcium carbonate solids that include particles and an alkaline carbonate solution; a dewatering apparatus that includes an input coupled to the crystallizer and an output to discharge a plurality of separate streams that each include a portion of the crystalline calcium carbonate solids and alkaline carbonate solution; and a seed transfer apparatus to deliver seed material into the crystallizer to maintain a consistent mass of seed material.

Abstract: Provided is a method of fixing a sufficient amount of carbon dioxide contained in a carbon dioxide-containing gas (e.g., a plant exhaust gas) simply, at low cost, and efficiently. The method of fixing carbon dioxide includes a contact step of bringing a carbon dioxide-containing gas into contact with powdery or grainy particles, which are each formed of a cementitious hardened body and each have a particle size of 40 mm or less, at a temperature of from 75° C. to 110° C. to fix carbon dioxide contained in the carbon dioxide-containing gas to the powdery or grainy particles, wherein the relative humidity of the carbon dioxide-containing gas is adjusted in accordance with the particle size of the powdery or grainy particles and the state of adjustment of moisture content of the powdery or grainy particles before the contact step.

Abstract: A purification composition, comprising 50-60% by weight of ash and 40-50% by weight of liquid. A method for producing the purification composition, comprising: measuring an amount of ash, combining the ash and liquid, wherein an amount of the liquid is based on the amount of the ash, adjusting a temperature of the combination of the ash and the liquid by adjusting a temperature of the liquid and mixing the ash and the liquid. A method for purifying a flue gas by the purification composition, comprising: combining the purification composition and vapour to form a chute, adding the chute to the flue gas, adding the purification composition to the flue gas and over-pressuring the flue gas and adding more of the purification composition to the flue gas and under-pressuring the flue gas.

Abstract: The embodiment provides a composite that allows the release of acid gas, even the continuous release of acid gas, at low temperature and with a high acid-gas release rate in a regeneration tower of an acid gas removal apparatus, and a regenerator and an acid gas removal apparatus, in both of which the composite is used, and a method of acid gas removal. The composite according to the embodiment is capable of separating an acid gas from an acid gas absorbent, which has absorbed the acid gas, to regenerate the acid gas absorbent, wherein the composite contains an inorganic layered compound and an aluminum-containing oxide. Also provided are a regenerator using the composite to regenerate an acid gas absorbent that has absorbed an acid gas by allowing the acid gas absorbent to release the acid gas, and an acid gas removal apparatus equipped with the regenerator.

Abstract: There is disclosed a washable paint composition suitable for use by children. The composition includes one or more pigments, specific extender pigments, alkali soluble thickeners and non-volatile neutralisers in an amount that allows the paint composition, should it come in contact with a cotton based textile, to be solubilised in a water solution and washed from the textile without leaving a stain.

Abstract: The invention discloses a method of producing a filler composition to be used in paper or board production, said method comprising providing a suspension comprising calcium hydroxide and performing carbonation of the calcium hydroxide to form precipitated calcium carbonate (PCC). The invention is characterized in that starch and/or carboxy methyl cellulose (CMC) is added to the suspension during said carbonation of calcium hydroxide. The method of the invention enables an increased filler content in paper or paperboard without substantially increasing the dusting tendency or decreasing the strength of the paper or board.

Abstract: Provided are a calcium carbonate having a small particle diameter and easily dispersible in polymers and a production method therefor. A calcium carbonate has a magnesium content of 12000 to 120000 ppm, a BET specific surface area of 60 to 120 m2/g, and a crystallite size of (104) plane of 20 to 50 nm, and particles of the calcium carbonate are concatenated.

Abstract: Reactor for enzymatic hydrolysis of a raw material comprising in sequence: i)—a first heat exchanger adapted to heat the raw material supplied to the reactor to a temperature within a range that favours enzymatic hydrolysis, ii)—a reactor comprising plural in reactor chambers connected in series, separated by closable valves, iii)—a second heat exchanger adapted to heat the reaction mixture to a temperature higher than the temperature range favouring enzymatic hydrolysis, the reactor being formed with inclined tubular reactor chambers assembled to form a reactor with vertical axis, the first reactor chamber being the vertically uppermost chamber of the reactor, while at least one reactor chamber is adapted to be stirred with a through-flowing inert gas.

Abstract: The subject invention provides systems and methods for capturing carbon dioxide in a cyclic process of mechano-chemical reactions. The subject invention also provides systems and methods for synthesizing siderite, by means of mechano-chemical reactions, using mill rotation. Siderite acts as an efficient reversible sorbent and can be decomposed, generating magnetite, carbon and/or metallic iron as well as pure carbon dioxide. Said systems and methods employing carbon dioxide capture/release reactions in the carbonation-calcination cycles are suitable for using in any iron, steel and non-steel industries to reduce carbon dioxide emissions into the atmosphere.

Abstract: This application provides a process for mineral carbonation, which process comprises the steps of: providing a bed of hydroxylated magnesium silicate mineral particles in a heating vessel; agitating the bed of particles under conditions of a sub-atmospheric pressure and at a temperature of at least 600° C. to produce particles of dehydroxylated magnesium silicate mineral; and reacting the dehydroxylated magnesium silicate mineral with carbon dioxide, carbonate ions and/or bicarbonate ions to form magnesium carbonate. This application also provides a reactor system for carrying out the process, which includes (1) mineral from mine, (2) hydroxylated magnesium silicate mineral, (3) crushing, grinding, sizing, (4) agitated bed of particles, (5) external heating, (6) vacuum system, (7) from carbon source, (8) carbon dioxide or carbonate or bicarbonate ions in solution, (9) carbonation reactions, (10) carbonate product, (11) pre-heat, (12) heat recovery, and (13) magnetic fraction.

Abstract: A method of utilizing construction and demolition waste is disclosed. The method comprises pretreating the construction and demolition waste into particles with a predetermined range of size; and obtaining calcium carbonate from the particles. The method of the present invention enables to recycle a wide range of construction and demolition waste, furthermore it can convert these waste materials into the high purity calcium carbonate which can be widely used in many applications.

Abstract: The invention relates to a particularly energy efficient, two-step method and to a system for the continuous or semicontinuous production of crystalline calcium carbonate (precipitated calcium carbonate, PCC) by reacting calcium hydroxide with CO2, the calcium hydroxide being lime milk. In the first step of the germination, the CO2-source is exclusively flue gas having a CO2-content of between 4-25% <sb/><sb/>. In the second step, the complete conversion of the lime milk reacted in the first step to a maximum of 90%, preferably between 10-90%, is carried out exclusively using a rich gas which comprises 30-99% CO2, preferably using biogas.

Abstract: The present invention provides a process for preparing a precipitated calcium carbonate product comprising the steps of: (a) 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, per mole of Ca(OH)2, (b) dewatering and dispersing the precipitated calcium carbonate seeds prepared in step (a) to obtain an aqueous suspension of precipitated calcium carbonate seeds having a d50 of less than or equal to 0.1 to 0.3 ?m and a BET specific surface area of 10 to 30 m2/g, and (c) forming an aqueous suspension of a precipitated calcium carbonate product by carbonating a slurry of Ca(OH)2 in the presence of 0.

Abstract: A process is shown for manufacturing a milk of lime of great fineness which includes at least the steps of providing one lime compound chosen in the group consisting of prehydrated lime, a paste of lime obtained by addition of water to quicklime instead of addition of quicklime to water and their mixture, and forming a milk of slaked lime of great fineness with the chosen lime compound. The paste of lime is obtained by progressive addition of water to quicklime under agitation conditions.

Abstract: A carbon capture system includes a Carbonator for adsorbing carbon dioxide with a carbon dioxide lean sorbent generating a carbon dioxide rich sorbent, a first Calciner for thermally decomposing a carbon dioxide rich sorbent into a carbon dioxide lean sorbent and carbon dioxide, a supply of raw material to be calcined into the first Calciner containing a carbon dioxide rich sorbent, a connection between the first Calciner and the Carbonator, a second Calciner for thermally decomposing a carbon dioxide rich sorbent into a carbon dioxide lean sorbent and carbon dioxide, a connection between the Carbonator and the second Calciner, and a connection between the second Calciner and the Carbonator.

Abstract: The present invention provides a process for preparing a precipitated calcium carbonate product comprising the steps of: (a) 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, per mole of Ca(OH)2, (b) dewatering and dispersing the precipitated calcium carbonate seeds prepared in step (a) to obtain an aqueous suspension of precipitated calcium carbonate seeds having a d50 of less than or equal to 0.1 to 0.3 ?m and a BET specific surface area of 10 to 30 m2/g, and (c) forming an aqueous suspension of a precipitated calcium carbonate product by carbonating a slurry of Ca(OH)2 in the presence of 0.

Abstract: The present invention refers to a process to modify at least part of the surface of at least one mineral material, and to the use, as an additive in an aqueous suspension of mineral materials having a pH between 5 and 10, of at least one agent, wherein the additive allows for the formation of a low volume, high solids content filter or centrifuge cake on dewatering the suspension.

Abstract: Dietary calcium supplements comprising highly bioavailable forms of calcium carbonate and methods of using these calcium carbonate forms to improve calcium balance, strengthen bones, and prevent, treat, and/or ameliorate bone loss associated with osteoporosis are provided.

Abstract: The present invention relates to an economic process for preparing surface-reacted calcium carbonate. The present invention further relates to a surface-reacted calcium carbonate having an increased specific BET surface area, and the use of a process for adjusting the specific BET surface area.

Abstract: A process for capturing undesirable combustion products produced in a high temperature combustion system in which a carbonaceous fuel is utilized. Very finely sized particles of alkaline earth carbonates or hydroxides, with or without added ground ash, are provided in slurry form, are dried and milled to provide unagglomerated, sub-micron-sized particles that are injected along with pulverized coal into the high temperature combustion zone of a furnace. The particles capture and neutralize the gases that result in condensable acids, including SOx, NOx, HCL, and HF, as well as capturing toxic metals that are present in the combustion products, they mitigate ash fouling and slagging, and they facilitate economic heat exchange that permits fuel savings and recovery of water for use in other processes.

Abstract: A method for preparing a suspension of LDH particles comprises the steps of preparing LDH precipitates by coprecipitation to form a mixture of LDH precipitates and solution; separating the LDH precipitates from the solution; washing the LDH precipitates to remove residual ions; mixing the LDH precipitates with water; and subjecting the mixture of LDH particles and water from step (d) to a hydrothermal treatment step by heating to a temperature of from greater than 80° C. to 150° C. for a period of about 1 hour to about 48 hours to form a well dispersed suspension of LDH particles in water.

Abstract: Acicular strontium carbonate particles are manufactured by introducing gaseous carbon dioxide into an aqueous solution or suspension of strontium hydroxide having a concentration of 1 to 20 wt. %, at a flow rate of 0.5 to 200 mL/min., relative to one gram of the strontium hydroxide, while stirring the solution or suspension in the presence of a dicarboxylic acid, in which the dicarboxylic acid comprises a divalent linear hydrocarbon group having one to four carbon atoms and carboxyl group bonded to each terminals, with the proviso that the linear hydrocarbon group may be substituted with one or more C1-6 alkyl groups, and thus carbonating the strontium hydroxide.

Abstract: The present invention relates to a process for the production of precipitated calcium carbonate, comprising the following steps: a) providing a reaction vessel containing an aqueous phase at an initial temperature; b) injecting a carbon dioxide generating compound into the aqueous phase until the pH of the aqueous phase is in the range of around 5 to around 7; and c) subsequently adding a calcium hydroxide slurry at an initial temperature to the reaction vessel while continuing the injection of the carbon dioxide generating compound, in order to obtain an aqueous slurry of the precipitated calcium carbonate. The addition rate of the calcium hydroxide slurry to the reaction vessel in step c) is such that an average electrical conductivity of the reaction contents in the reaction vessel during the reaction is in a range of 100 to 6 000 ?S/cm.

Abstract: The present invention concerns an anti-deposit additive and a deposit and/or corrosion reducing aqueous slurry containing a calcium carbonate containing material. In particular, the present invention is directed to the use of at least one anionically charged comb polymer as an anti-deposit agent in an aqueous slurry comprising a calcium carbonate containing material.

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 (?)}i) 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 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: The present invention relates to a process for the preparation of precipitated calcium carbonate comprising the steps of a) providing and calcining calcium carbonate comprising material; b) slaking the reaction product obtained from step a) with an aqueous ammonium chloride solution; c) separating insoluble components from the calcium chloride solution obtained from step b); d) carbonating the calcium chloride solution obtained from step c); e) separating the precipitated calcium carbonate obtained from step d); the precipitated calcium carbonate obtained by this process, as well as uses thereof.

Abstract: The invention relates to novel and innovative PCC pigments, able to be used in a paper coating formulations to manufacture coated “multipurpose” papers, in particular for inkjet applications, whose print qualities would be identical or quite similar to high resolution commercial papers, while maintaining a reduced paper manufacturing and production cost. Said pigments are obtained by a carbonation process using a reduced flow rate of CO2/air, which leads to porous agglomerates of PCC of a very specific structure and unique properties, followed by an upconcentration step leading to substantially the same agglomerates but with a higher, appropriate, solids content.

Abstract: The present invention provides a process for preparing a precipitated calcium carbonate product. The process comprises the steps of preparing slaking quick time to obtain slaked lime; and subjecting the slaked lime, without agitation, without prior cooling in a heat exchanger, and in the absence of any additives, to carbonation with carbon dioxide as to produce PCC. The newly prepared product develops better performance thanks to improved resistance during processing.

Abstract: The invention relates to novel and innovative PCC pigments, able to be used in a paper coating formulations to manufacture coated “multipurpose” papers, in particular for inkjet applications, whose print qualities would be identical or quite similar to high resolution commercial papers, while maintaining a reduced paper manufacturing and production cost. Said pigments are obtained by a carbonation process using a reduced flow rate of CO2/air, which leads to porous agglomerates of PCC of a very specific structure and unique properties, followed by an upconcentration step leading to substantially the same agglomerates but with a higher, appropriate, solids content.

Abstract: The present invention relates to a process for the production of precipitated calcium carbonate, comprising the following steps: a) providing a reaction vessel containing an aqueous phase at an initial temperature; b) injecting a carbon dioxide generating compound into the aqueous phase until the pH of the aqueous phase is in the range of around 5 to around 7; and c) subsequently adding a calcium hydroxide slurry at an initial temperature to the reaction vessel while continuing the injection of the carbon dioxide generating compound, in order to obtain an aqueous slurry of the precipitated calcium carbonate. The addition rate of the calcium hydroxide slurry to the reaction vessel in step c) is such that an average electrical conductivity of the reaction contents in the reaction vessel during the reaction is in a range of 100 to 6 000 ?S/cm.

Abstract: Novel and innovative PCC pigments, having a reduced production cost, able to be used in a paper coating formulations to manufacture coated high-quality matt papers, in particular for inkjet applications. Process for the preparation of same, using a reduced flow rate of a carbon dioxide-containing gas in the PCC carbonation step, which produces stable, porous, agglomerates of PCC featuring unique properties and structure, this step being followed by an upconcentration step to increase the solids content.

Abstract: All of the methods and devices disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the methods and devices of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the methods and devices and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit, and scope of the invention. More specifically, it will be apparent that certain compositions which are chemically related may be substituted for the compositions described herein while the same or similar results would be achieved. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope, and concept of the invention as defined by the appended claims.

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: A process for capturing CO2 includes contacting a CO2-containing gas with an absorption mixture optionally within a packed reactor is provided. The absorption mixture includes a liquid solution and micro-particles. The micro-particles include a support material and biocatalyst supported by the support material and are sized and provided in a concentration such that the absorption mixture flows through the packed reactor and that the micro-particles are carried with the liquid solution to promote dissolution and transformation of CO2 into bicarbonate and hydrogen ions. The absorption mixture and micro-particles may be provided in an absorption reactor so as to be pumpable. Furthermore, a process for desorbing CO2 gas from an ion-rich aqueous mixture includes providing biocatalytic micro-particles and feeding the mixture to a desorption reactor, to promote transformation of the bicarbonate and hydrogen ions into CO2 gas and water.

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: 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: Techniques for converting a portion of a carbonate to hydroxide include receiving an alkaline carbonate solution that includes between 0.1M (moles per liter of solution) to 4.0M hydroxide and between 0.1M to 4.1M carbonate; reacting, in a slaking process, quicklime (CaO) and a low carbonate content fluid to yield a slurry of primarily slaked lime (Ca(OH)2); and reacting the Ca(OH)2 slurry and the alkaline carbonate solution to grow calcium carbonate (CaCO3) crystal aggregates of 0.0005 mm3 to 5 mm3 in volume in a fluidized-bed reactive crystallizer.

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: 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: The present invention relates to a filler or a filler mixture containing carbonate, as well as to a process for manufacturing the same by precipitating the filler directly into the pulp or, as a separate process without the presence of fibres, particularly from the wire water of the paper or board manufacture. The invention also relates to a fibre product containing this filler, such as a paper or board product, or a plastic, rubber, concrete or paint product.

Abstract: Acicular strontium carbonate particles are manufactured by introducing gaseous carbon dioxide into an aqueous solution or suspension of strontium hydroxide having a concentration of 1 to 20 wt. %, at a flow rate of 0.5 to 200 mL/min., relative to one gram of the strontium hydroxide, while stirring the solution or suspension in the presence of a dicarboxylic acid, in which the dicarboxylic acid comprises a divalent linear hydrocarbon group having one to four carbon atoms and carboxyl group bonded to each terminals, with the proviso that the linear hydrocarbon group may be substituted with one or more C1-6 alkyl groups, and thus carbonating the strontium hydroxide.

Abstract: To provide a method for producing a carbonate, including: growing seed crystals, wherein the seed crystals are grown in a reaction solution containing at least urea. An aspect in which the seed crystals are strontium carbonate particles, an aspect in which the reaction solution contains a metal ion source and the metal ion source is a hydroxide of strontium, and the like are favorable.

Abstract: A method of producing calcium carbonate from a waste sludge containing calcium carbonate and at least one silicate mineral. The method comprises the steps of: (i) incinerating the sludge to an ash in which at least 60% of the calcium carbonate present in the sludge is converted to free calcium oxide which is unreacted with the silicate mineral(s), (ii) optionally slaking the ash to convert at least a portion of the free calcium oxide therein to calcium hydroxide, (iii) treating either the ash from step (i) or the slaked ash from step (ii) with an aqueous solution of a polyhydroxy compound to provide a solution of dissolved calcium hydroxide, (iv) separating insoluble material from the solution of calcium ions obtained in step (iii), (v) dispersing carbon dioxide through the solution obtained from step (iv) so as to produce calcium carbonate, and (vi) separating the calcium carbonate produced in step (v).

Abstract: The present invention relates to a process for preparing hydromagnesite in an aqueous environment. The invention further relates to such hydromagnesite having a specific platy-like morphology in combination with a specific average particle size and to their use as minerals, fillers and pigments in the paper, paint, rubber and plastics industries and to the use as flame-retardant.

Abstract: The present invention relates to a process for the preparation of precipitated calcium carbonate comprising the steps of a) providing and calcining calcium carbonate comprising material; b) slaking the reaction product obtained from step a) with an aqueous ammonium chloride solution; c) separating insoluble components from the calcium chloride solution obtained from step b); d) carbonating the calcium chloride solution obtained from step c); e) separating the precipitated calcium carbonate obtained from step d); the precipitated calcium carbonate obtained by this process, as well as uses thereof.

Abstract: The present invention concerns a method for producing calcium carbonate containing the steps of extraction of alkaline industrial waste or by-products using as a first extraction solvent an aqueous solution of a salt formed from a weak acid and a weak base, whereby a vanadium-enriched first residue is allowed to settle and a calcium-rich first filtrate is formed, filtration, whereby the first filtrate is separated from the first residue, carbonation of the calcium-rich first filtrate using a carbonation gas, whereby calcium carbonate precipitates and a second filtrate is formed, and a second filtration, whereby the calcium carbonate is separated from the second filtrate. Further, the present invention concerns a method for extracting calcium carbonate and vanadium from alkaline industrial waste or by-products.

Abstract: The present invention relates to a method for preparing barium carbonate and the barium carbonate product obtained by the method. The method for preparing barium carbonate comprises: (1) Adding barium hydroxide octahydrate crystal into the ice-water bath and mixing them, and controlling the temperature to be within 0˜5° C.; (2) Introducing carbon dioxide into the mixture obtained from the step (1), till pH value of the reaction solution reaches 6.0-7.0; (3) Carrying out solid-liquid separation for the solid-liquid mixture obtained from the step (2), drying the obtained solid so as to obtain barium carbonate product. The present invention method solves the problem in the prior art that the character of low strontium and the character of large specific surface area can not co-exist, which makes the property of barium carbonate product can not affect the sintering temperature, and thus the property material is improved.