Abstract: A furnace may include at least two vertical shafts, each of which may have at an upper end thereof an inlet for material to be burnt and at a lower end thereof a burnt material outlet. The inlet and the outlet may be connected by a transfer channel. In each case, at least one main burner may be positioned above the transfer channel, and a cooling gas inlet may be positioned below the transfer channel. At least one additional burner may be positioned below the transfer channel in each of the shafts. Such a furnace can be operated such that the material to be burnt in the currently fired shaft is at least partially calcined in a main burning zone above the transfer channel, and then thermally aftertreated in an additional burning zone positioned between the transfer channel and the additional burner.

Abstract: Apparatuses, systems, and methods related to removing carbon dioxide from a gas stream are provided. Gas streams can be waste gas streams or natural gas streams. The systems and methods for removing carbon dioxide incorporate water repurposing schemes. Still others are disclosed.

Abstract: The present invention is directed to a method of continuously calcining a limestone particle mix comprising a fine fraction of limestone particles and a coarser fraction of limestone particles. The limestone particles heat treated in a flash calciner in which the mixture is entrained and heated in process gas for an amount of time sufficient to fully calcine the fine fraction but not the coarser fraction. The process gas is separated from the heated limestone mixture. The mixture is directed to a retention vessel in which the mixture is retained for an amount of time sufficient to fully calcine the coarser fraction utilizing the process heat present in the limestone mixture. No external heat needs to be added to the retention vessel during the retention step to promote calcination.

Abstract: The present invention may provide talc calciner systems and methods to produce better and more efficient products by engineering a* and b* values for calcinated products perhaps by processing low iron talc in an indirectly heated, multiple zoned calciner which may progressively heat the feed supply at perhaps specifics residence times to produce a desired product.

Abstract: The present invention relates to an energy efficient carbon dioxide sequestration processes whereby Group 2 silicate minerals and CO2 are converted into limestone and sand using a two-salt thermolytic process that allows for the cycling of heat and chemicals from one step to another.

Abstract: Method for batch wise slaking of burnt lime in a slaker, in which a lime slurry is produced with a great degree of fineness and long sedimentation time, comprising the following steps: the regulation of the slaking temperature is carried out in either of two steps—at incoming water temperatures between 0-10° C. a predetermined amount of the finished slurry is emptied out—at incoming water temperatures between 10-20° C. a predetermined amount of flushing water or diluting water is added.

Abstract: The invention features methods and systems for producing commercial quality carbon dioxide (CO2) of 90% to +99% purity using, wet calcium carbonate lime mud produced in a manufacturing operation, for instance, Kraft pulp mill lime mud (a.k.a., “lime mud”) as a feedstock to a multi-stage lime mud calcination process. This process may be fueled with waste water treatment plant (WWTP), sludge biomass, precipitated lignins, coal, or other low cost solid fuels. High reactivity “soft-burned” lime product (“calcine”) required in the mill's chemical recovery circuit is also produced, and steam and heated boiler feed-water is generated and exported to the mill's steam distribution and generation system as well as hot process water for use in the mill's boiler house and manufacturing operation.

Abstract: A powder lime calcining process comprises: transporting fine granules of limestones having a water content less than 4%, and a granule size less than 15 mm, from a raw material storing bin to a small material bin, transporting the materials from the small material bin into an airflow pipe by a belt conveyer, heating and drying the materials, sieving the materials by a sieving device, transporting granules into a cyclone cylinder deduster and a clothbag deduster in turn by airflow pipes, the fine powders of limestones after dedusted are transported into an intermediate bin; the materials within the intermediate bin are transported to four preheating cyclone cylinders by a pneumatic lift pump and airflow pipes, and are preheated and separated; the materials after separated are transported into three cooling cyclone cylinders for cooling and separating the materials, finally transported into a finished product bin by a finished product transporting system.

Abstract: According to the invention, the method for burning fragmented material is carried out in at least one shaft which comprises a preheating zone, a combustion zone and a cooling zone, coal having a swelling index>1 being supplied via combustion lances, and the temperature of the coal in the combustion lances being maintained below a temperature value at which melting phases of the coal used are formed.

Abstract: The invention relates to a method for producing quick lime from lime stone in a continuous regenerative shaft kiln, characterized in that, starting with standard conditions of excessive combustion air for the operation of this kiln, it especially includes a step where the excessive combustion air is progressively reduced until a content greater than 1000 ppm (in volume) of carbon monoxide is reached in the connection flue between the tanks. An increase in the content of gaseous sulphur dioxide is then observed in the gas flue, with respect to a kiln operated in standard conditions.

Abstract: The present invention relates to a method and an arrangement for burning lime mud into lime in a lime kiln The lime mud flows counter-currently to flue gases from a feed end to a firing end and the fuel used is flue gas that is produced by gasifying a fuel in the presence of combustion air in a gasifier. The combustion air for gasification is preheated with heat generated in lime mud combustion. The arrangement is provided with a conduit between the lime kiln and the gasifier for leading air from the lime kiln into the gasifier as combustion air. At least a portion of the combustion air for gasification is preheated with heat generated in the lime mud combustion so that air is led into cooling of lime obtained in the combustion and further into the kiln, from or through the firing end of which air is taken into the gasification.

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: This application concerns methods and apparatus for use in industrial waste recovery operations such as recovery of non-consumed chemicals in industrial processes, with recovery of quick lime in a wood pulp process being an example. In some embodiments, methods comprise baking lime sludge in a kiln and controlling a temperature in a calcining zone of the kiln to be above about 2250° F. to vaporize sodium contained in the lime sludge. Interaction of the vaporized sodium with SOx can deter accumulation of one or both of CaCO3 and CaSO4 on one or more inner surfaces of the kiln. In some embodiments, lime sludge can be rinsed to generate a filtrate comprising dissolved NaOH, and the filtrate can charge a scrubber for removing SOx from an exhaust from the kiln. Embodiments of co-fired burners for heating such kilns by burning petroleum coke and natural gas are also disclosed.

Abstract: A powder lime calcining process comprises: transporting fine granules of limestones having a water content less than 4%, and a granule size less than 15 mm, from a raw material storing bin to a small material bin, transporting the materials from the small material bin into an airflow pipe by a belt conveyer, heating and drying the materials, sieving the materials by a sieving device, transporting granules into a cyclone cylinder deduster and a clothbag deduster in turn by airflow pipes, the fine powders of limestones after dedusted are transported into an intermediate bin; the materials within the intermediate bin are transported to four preheating cyclone cylinders by a pneumatic lift pump and airflow pipes, and are preheated and separated; the materials after separated are transported into three cooling cyclone cylinders for cooling and separating the materials, finally transported into a finished product bin by a finished product transporting system.

Abstract: A method for preparing carbonate apatite from natural bones. The method includes obtaining cancellous bone particles; treating the bone particles with hot water and an organic solvent; repeating the treating step at least once; drying the bone particles; and heating the bone particles at 500° C. to 620° C. for 10 to 50 hours.

Abstract: The method of producing soda ash and calcium chloride provides an environmentally friendly method of producing soda ash and calcium chloride without the production of waste and hazardous byproducts. The method of producing soda ash and calcium chloride is initiated with a volume of brine, which is ammoniated with gaseous ammonia to form ammoniated brine. Limestone is heated to produce calcium oxide and carbon dioxide. The ammoniated brine is reacted with the carbon dioxide to produce sodium bicarbonate, ammonium chloride and a brine effluent. The sodium bicarbonate is then calcined and decomposed to produce soda ash and gaseous carbon dioxide. The calcium oxide is reacted with the ammonium chloride to produce calcium chloride, water and ammonia. The ammonia is recycled to be used in the initial step of ammoniating the brine. The water and the brine effluent are also recycled and used to provide the brine in the initial step.

Abstract: Disclosed is a method for calcining a natural chalk powder within a rotary kiln. The powder is inserted into the kiln accompanied by an additive that promotes nodulization of the powder to thereby facilitate the treatment of the chalk powder within the rotary kiln. The nodulization takes place at temperatures less than the calcining temperatures of the chalk and prior to the nodulized chalk being calcined within the kiln.

Abstract: The present invention relates to a method of precipitation of metal ions. Mineral(s), oxide(s), hydroxide(s) of magnesium and/or calcium are adopted as raw materials, and the raw material(s) is processed through at least one step of calcination, slaking, or carbonization to produce aqueous solution(s) of magnesium bicarbonate and/or calcium bicarbonate, and then the solution(s) is used as precipitant(s) to deposit rare earth, such as nickel, cobalt, iron, aluminum, gallium, indium, manganese, cadmium, zirconium, hafnium, strontium, barium, copper and zinc ions. And at least one of metal carbonates, hydroxides or basic carbonates is obtained, or furthermore the obtained products are calcined to produce metal oxides. The invention takes the cheap calcium and/or magnesium minerals or their oxides, hydroxides with low purity as raw materials to instead common precipitants such as ammonium bicarbonate and sodium carbonate etc.

Abstract: The application of aqueous solution of magnesium bicarbonate and/or calcium bicarbonate in the process of extraction separation and purification of metals is disclosed, wherein the aqueous solution of magnesium bicarbonate and/or calcium bicarbonate is used as an acidity balancing agent, in order to adjust the balancing pH value of the extraction separation process which uses an acidic organic extractant, improve the extraction capacity of organic phase, and increase the concentration of metal ions in the loaded organic phase.

Abstract: The invention relates to a method for producing quick lime from lime stone in a continuous regenerative shaft kiln, characterised in that, starting with standard conditions of excessive combustion air for the operation of this kiln, it especially includes a step where the excessive combustion air is progressively reduced until a content greater than 1000 ppm (in volume) of carbon monoxide is reached in the connection flue between the tanks. An increase in the content of gaseous sulphur dioxide is then observed in the gas flue, with respect to a kiln operated in standard conditions.

Abstract: A method of making magnesium hydroxide may include calcining a mineral source of magnesium carbonate to form magnesium oxide, and slaking the magnesium oxide in water. When the mineral source of magnesium carbonate further includes a mineral source of calcium carbonate, the calcination may be carried out such that less than about 20 wt % calcium oxide is formed following calcining and prior to slaking in water.

Abstract: Disclosed is a processes for the production of relatively high purity alkaline earth metal oxides, such as SrO, from relatively low purity forms of carbonated or other oxygenated forms of such metals, such as strontium carbonate. The relatively low purity material is exposed to conditions under which at least a portion of the metal contained therein is converted to a salt that is more readily solvated in a provided solvent than the starting material, while at the same time not substantially increasing the solubility of at least one or more of the impurities in such selected solvent. This step is then preferably followed by removal of solid or otherwise un-dissolved impurities from the solution. After the removal step, the solution is preferably exposed to conditions effective to form a relatively insoluble salt of the alkaline earth metal, such as a strontium salt. The insoluble salt is also preferably one that can be readily and effectively converted to the desired alkaline earth metal oxide, preferably SrO.

Abstract: Applying an acid treatment to eggshells provides a sorbent with unexpectedly high CO2 capture capacity and ability to regenerate.

Abstract: This invention provides a method for reducing phosphorous in a body of water. This method comprises calcining a plurality of rocks and collecting carbon dioxide formed as a result of the calcining process; crushing the plurality of calcined rocks; pumping source water from the body of water into to a plurality of retaining cells; flocculating the phosphorus in the source water by introducing the plurality of calcined rocks into the source water in the retaining cells; settling out a phosphorous precipitate formed by the flocculating act; adjusting the pH level of the flocculated source water to a predetermined range of values by pumping carbon dioxide created by the calcining of the rocks into the source water to created treated water; and transferring the treated water back to the body of water.

Abstract: The invention concerns an air box (1) in a regenerative thermal oxidiser comprising one or several beds (3) of a heat-storing and heat-transferring material. The air box (1) is connected with a gas inlet/outlet (2) and comprises a gas permeable surface (9) that is turned towards one of said beds (3). The air box (1) is further characterised in that distribution means (4) are provided in said air box (1).

Abstract: The present invention reduces the sulfur and odor emissions from a paper-making Kraft process by recovering the sulfur in the non-combustible gases (NGCs) emitted by the Kraft process. In a first embodiment of the invention, the NGCs are flamelessly oxidized in a flameless thermal oxidizer to form a sulfur oxide-containing, gaseous products stream. The gaseous products stream is scrubbed with a scrubber solution stream to remove the sulfur components resulting in a scrubbed gas stream and spent scrubber solution stream having S.sub.2 O.sub.3 and SO.sub.4, and SO.sub.3 soluble salts. At least a portion of the spent scrubber solution from the scrubber is directed back into the Kraft process, thus recovering the sulfur. In a second general embodiment of the invention, the NGCs are flamelessly oxidized in a moving, packed bed calcinator. The calcinator receives a lime mud stream from the Kraft process, forms a packed bed therefrom, calcines the packed bed, and releases it as a quick lime stream.

Abstract: A lime regeneration method and system of apparatus which compacts lime mud into agglomerates of predetermined configurations for improved handling and processing in a subsequent compact, efficient, minimally polluting and low cost reactor vessel in which the mud is dried, heated, calcined and cooled to form a reactive lime product.

Abstract: A method and plant for heat treatment of lime sludge (CaCO.sub.3) formed by the causticizing process during the manufacture of paper pulp. The lime sludge is dried and pulverized in a first process stage and preheated in a second process stage by means of hot exhaust gas coming from a kiln. In order to ensure that the temperature in the second process stage does not exceed a predetermined temperature lying within the range from 400.degree.-600.degree. C., the relationship between the amount of energy available in the exhaust gas for preheating in the second process stage and the amount of accumulated energy in the material which is to be preheated is regulated.

Abstract: A stabilized, pressure-hydrated magnesium hydroxide slurry and a process for its production from burnt magnesite are described. According to an embodiment of the invention, a mixture comprising burnt natural magnesite and water is pressure hydrated to provide a pressure hydrated slurry. The pressure hydrated slurry is then deagglomerated. If desired, chloride ions and cationic polymer can be added to further stabilize the slurry.

Abstract: An antimicrobial agent contains a calcined product of a calcium oxide type prepared by calcining shells of an oyster and/or a calcined product of a calcium hydroxide type as a hydrate of the calcined product of the calcium oxide type.

Abstract: A process for calcining limestone to lime to produce a low sulfur content lime product, while combusting a sulfur-containing carbonaceous fuel in a rotary kiln to provide heat for the calcination. A finely divided lime hydrate is added to the rotary kiln adjacent the combustion flame, such that the lime hydrate particles react with sulfur-containing contaminants in the hot combustion gases to form lime hydrate-sulfur reaction products, such as calcium sulfate, which are retained in the gaseous flow and removed from the rotary kiln.

Abstract: Lime mud from kraft pulp recovery operations is processed using dielectric hysteresis heating, in a two-stage operation, in which wet lime mud first is dried then the dried lime mud is decomposed to lime and carbon dioxide. A two-zone lime mud calciner is employed in which the lime mud is conveyed horizontally, with drying being effected in the first zone and then decomposition being effected in the second zone. A co-current flow of purge air removes steam generated in the first zone and a counter-current flow of purge air removes carbon dioxide generated in the second zone.

Abstract: Disclosed is a method and an apparatus for the heat treatment of lime sludge (CaCO.sub.3) to form burnt lime (CaO). In the method of the present invention lime sludge is dried in a gas dryer means, to produce a dried lime sludge. The dried lime sludge is separated from the gases and thereafter is first fed to a compacting means wherein it is compacted into a plurality of substantially uniform bodies which are thereafter fed to a shaft kiln in which the compacted dried lime sludge is converted to active burnt lime.

Abstract: A process for the continuous production of a calcined product containing a high level of reactive oxide valves, from a preheated raw material containing calcium carbonate values, said process comprising,(a) introducing the preheated raw material to the bottom of a generally vertically oriented gas suspension calcining furnace, whereby said preheated raw material is thereafter suspended in an ascending stream of heated gas to thereby pass vertically upwardly through the gas suspension calcining furnace;(b) passing the ascending gas stream through a plurality of burners, into which fuel and air are injected, that are vertically spaced from each other, in the gas suspension furnace, at a number of levels in the flow direction of the heated gas, and(c) collecting the calcined product.

Abstract: This is a process and a device making use of a process for forming calcium oxide from pulverulent calcium carbonate, according to which an initial bath of pulverulent calcium oxide is produced in a reactor (1, 31) in the form of a fluidized bed which is heated electrically to a temperature higher than of the order of 900.degree. C., and the said pulverulent calcium carbonate is then introduced continuously into the bath while the temperature of the bath is always kept higher than of the order of 860.degree. C. by electrical heating, to dissociate the said calcium carbonate into calcium oxide and carbon dioxide.

Abstract: In the heat treatment of lime mud, the lime mud to be introduced to a lime reburning kiln is dried in a pneumatic drier by flue gases from the lime reburning kiln in order to regenerate the lime contained in the mud. Prior to drying, the lime mud is thickened in a drying filter to a dry solids content of over 75%, preferably to approximately 80%. In this way, the lime reburning kiln can be made approximately 30% shorter than conventional kilns, and the apparatus is simpler than the conventional apparatus provided with a pneumatic drier.

Abstract: Method and apparatus for controlling the reactivity of lime produced in a lime cycle process that includes the steps of forming burnt lime in a kiln, washing and filtering of lime sludge, and causticizing of green liquor, which lime cycle process steps are carried out under variable operating conditions. At least one mechanical property of the burnt lime is measured, and at least one operating condition of the time cycle process is adjusted, based on the measured mechanical property of the burnt lime, so as to thereby control the reactivity of lime produced in the lime cycle process.

Abstract: A process for producing magnesium oxide and/or hydrates thereof from predominantly magnesium or magnesium-calcium raw materials, and optionally producing calcium carbonate, whereby the raw material is roasted if necessary to form a mixture of magnesium oxide and calcium oxide. The calcium oxide is then dissolved from the mixture using an aqueous solution containing an organic amine and a salt of an organic amine with an acid capable of forming a soluble calcium salt with said organic amine. Separating the solution from the undissolved magnesium oxide and treating the solution with carbon dioxide will cause the dissolved calcium to be precipitated and calcium carbide.

Abstract: A method for calcination of a calcium carbonate material comprising heating the calcium carbonate material to a temperature and for a time sufficient to calcine the material to the degree desired while in the presence of a catalyst; said catalyst comprising at least one fused salt having the formulaMCO.sub.3.CaCO.sub.3.CaO.H.sub.2 O.sub.x,wherein M is an alkali metal and x is 0 to 1 and formed by fusing MCO.sub.3 and CaCO.sub.3 in a molar ratio of about 1:2 to 2:1, and a blend adapted to be heated to CaO comprising a calcium carbonate material and at least one such fused salt.

Abstract: Fine particulate solid fuel is utilized in the calcining or uniflow shaft of a uniflow regenerative shaft furnace having outlet openings of fuel lances of the furnace arranged with a uniform distribution over the cross-section of the furnace shaft in a horizontal plane between the preheating zone and the calcining zone of the furnace. The fuel feed is maintained constant with time by a dosing system through which fuel is supplied through feed lines to the fuel lances. Due to the uniform distribution of solid fuel which is accomplished, a calcined material is obtained which has a quality comparable to that which may be achieved through calcining with gaseous or liquid hydrocarbons.

Abstract: Energy conserving limestone calcining system, including a process and apparatus in which in a first step or kiln zone limestone is heated, e.g., at 1700.degree.-2100.degree. F., sufficiently to achieve more than only about 50 or 60%, e.g.

Abstract: High purity magnesium oxide is obtained from a magnesite-containing ore, the impurities of which include calcium compounds. The ore is first calcined and the resulting magnesium oxide is converted to magnesium chloride by leaching with an ammonium chloride solution. Calcium chloride is also produced at the same time. The resulting magnesium chloride and calcium chloride are treated with carbon dioxide to form calcium carbonate and magnesium carbonate which can be precipitated and filtered out of the resulting magnesium chloride solution. The magnesium chloride solution is then reacted with ammonium carbonate to produce a magnesium carbonate trihydrate crystal slurry containing ammonium chloride. The ammonium chloride is subsequently removed and returned to the ammonia recovery stage for leaching of the calcined magnesium oxide while the crystals are dried and decomposed into carbon dioxide and magnesium oxide.

Abstract: The invention relates to a process for the decarbonation of minerals, in powdered form, in a fluidized bed. For example, the process applies to the production of quick lime and/or magnesia from lime stone and/or dolomite fines which are not rendered sufficiently valuable at present.The process comprises recycling a portion at least of the carbon dioxide produced to be used as sole fluidizing gas, the fluidized bed being heated to the desired decarbonation temperature by direct heat supply within the fluidized bed by means of electric devices.Production of decarbonated minerals and of CO.sub.2.

Abstract: Process for the recovery of valuable metals, particularly rare earths and similar metals, which occur in a finely distributed condition in a raw material containing calcium carbonate.The raw material with the valuable elements is subjected to vigorous heating to decompose calcium carbonate and is allowed to react with sulphur oxides, particularly SO.sub.2, so that the calcium present is converted to insoluble calcium sulphate. The valuable metals are extracted from the calcine by extraction with dilute acid or water, whereafter the valuable metals are recovered from the extract in a per se known manner.The heating and the reaction with sulphur oxides may be carried out by mixing the raw material containing the valuable elements with sulphur or a combustible sulphurous material, such as pyrite, and subjecting it to exothermic combustion.

Abstract: A demolition agent for brittle materials which is prepared by pulverizing a quick lime clinker including 0.5 to 10.0% by weight of phosphorus components in terms of P.sub.2 O.sub.5.

Abstract: A nonexplosive chemical composition for gently and noiselessly breaking a rock or concrete mass. The composition comprises a principal component which is prepared by calcining a starting mixture comprising 100 parts by weight of quick lime and 1-20 parts by weight of calcium fluoride. In rock or concrete breaking operations, this composition in the form of aqueous slurry is poured into drill-holes and left to spontaneously hydrate and set with development of expansion pressure. For adequate retardation of the hydration, preferably a second fluoride such as Na.sub.2 SiF.sub.6 which gives CaF.sub.2 by reaction with CaO at the calcination temperature is added to the starting mixture. As an alternatively preferable method for the same purpose, an amino acid compound and/or a lignosulfonate is used as a hydration retarding agent which is mixed with the calcined principal component. Various auxiliary agents may optionally be added to this composition.

Abstract: The subject of the invention is a process for the production of pure burnt lime using gaseous fuels produced from energy carriers, in particular industrial wastes, wherein the energy carriers are gasified in an installation consisting of a fluidized bed and a cyclone, and the noxious substances released during the thermal decomposition are separated off by means of adsorbents, before they come into contact with the lime being burned.

Abstract: Very pure magnesium oxide is obtained from ore containing magnesium, more particularly ore containing magnesium carbonate, by calcining the ore and leaching the resulting magnesium oxide with carbon dioxide and calcium chloride solution to produce magnesium chloride solution. Carbon dioxide and ammonia are added, so as to precipitate magnesium carbonate trihydrate, which is decomposed to magnesium oxide.

Abstract: The instant invention is directed to a method of inhibiting and dispersing calcium oxide deposit formation in coal-fired lime kilns, comprising burning the coal in the presence of from 1 to 2 pounds/ton of coal of a blend of 80 to 95%, by weight, magnesium oxide and 5 to 20%, by weight, copperoxychloride.

Abstract: A stabilized, pressure-hydrated magnesium hydroxide slurry and a process for its production from burnt magnesite are described. According to an embodiment of the invention, a mixture comprising burnt natural magnesite and water is pressure hydrated to provide a pressure hydrated slurry. The pressure hydrated slurry is then deagglomerated. If desired, chloride ions and cationic polymer can be added to further stabilize the slurry.