Abstract: The present invention relates to a process for the purification of water, wherein a surface-reacted natural calcium carbonate is brought into contact with the water to be purified, the surface-reacted natural calcium carbonate being the reaction product of a natural calcium carbonate with an acid and carbon dioxide, which is formed in situ by the acid treatment and/or supplied externally.

Abstract: A method for removing impurities from a waste solid to provide at least a portion of a suitable crystallizer feed to a process for making crystalline sodium carbonate, bicarbonate, and/or other derivatives. The method comprises: contacting the waste solid with a leach solution to dissolve at least one impurity and dissolving the resulting leached residue. Leaching may include heap percolation. The leach solution may comprise a crystallizer purge liquor, a process waste effluent, a mine water, or mixtures thereof. The method may further comprise adding a magnesium compound to the resulting leached residue during or after its dissolution to remove another impurity. The waste solid preferably comprises a pond solid containing such impurities. The pond solid may be recovered from a pond receiving crystallizer purge liquor(s) and/or other process waste effluent(s). The pond solid may contain sodium carbonate, any hydrate thereof, sodium bicarbonate, and/or sodium sesquicarbonate.

Abstract: Kainite mixed salt is treated with water to obtain solid schoenite and a schoenite end liquor. The latter is desulphated using recycled CaCl2 and thereafter evaporated to obtain camallite crystals, from which KCl is recovered, and a liquor rich in MgCl2. Gypsum produced during desulphatation is reacted with aqueous ammonia and CO2 to produce ammonium sulphate and calcium carbonate. The calcium carbonate is calcined to obtained CaO and CO2. The CaO is slaked and reacted with the MgCl2-rich liquor generated above to produce slurry of Mg(OH)2 in aqueous CaCl2. To this surface modifying agent is added while hot and, after cooling, the slurry yields surface modified Mg(OH)2. The filtrate rich in CaCl2 is recycled for desulphatation process above. The solid surface modified Mg(OH)2 may he calcined to produced MgO. The schoenite and KCl are reacted to produce solid sulphate of potash.

Abstract: A method for feeding lime mud into a lime kiln including a rotary kiln shell having an interior between a first end wall and a second end wall, the method including: feeding the lime mud into a flue gas flow in the interior of the rotary kiln shell or in close proximity to the shell to pretreat the lime mud; separating the pretreated lime mud from the flue gas flow; conveying the separated lime mud into the lime kiln, and calcining the separated lime mud in the lime kiln.

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: A process designed to obtain potassium sulfate from vinasse where such vinasse is mainly obtained as a by-product of ethyl alcohol and the like production distilleries. Such process consists in concentrating vinasse dry solids for their subsequent combustion in a recovery boiler and to obtain electric power by activating a vapor turbine and at the same time recover the melted minerals from the boiler floor to obtain a chemical conversion reaction from carbonates to sulfates. Such reactions produce mainly Potassium sulfate in economic and technically sustainable production rates. Moreover, this process neutralizes the harmful effects of the vinasse polluting residue.

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: 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: The invention relates to a method of improving a material comprising a pozzolanic component. According to the invention the material is treated with an aqueous liquid resulting in treated, calcium-depleted material and a calcium-enriched aqueous solution, which are subsequently separated. This provides a material having an increased pozzolanity and/or increased specific surface area.

Abstract: A heat transfer fluid with hetero-nanocapsules. The heat transfer fluid comprises a fluid and a plurality of hetero-nanocapsules, uniformly dispersed in the fluid, in an amount of 0.01 to 10 parts by weight, based on 100 parts by weight of the heat transfer fluid. Since the hetero-nanocapsules are apt to disperse in fluid and have superior thermal conductivity, the heat conduction capability of the heat transfer fluid therewith is enhanced.

Abstract: A protective coating on a metal surface comprises a particulate material produced by a method including heating an animal skeletal material to a temperature of at least 1000° C. for a time sufficient to convert at least part of the calcium carbonate in the skeletal material to calcium oxide and produce a calcined product; and then contacting at least part of the calcined product with water to produce the particulate material containing calcium hydrate.

Abstract: A method of facilitating the crystallisation of a macromolecule comprising the step of adding a mesoporous glass to a crystallisation sample wherein the mesoporous glass comprises pores having diameters between 4 nm and 100 nm and has a surface area of at least 50 m2/g. A method of facilitating the crystallisation of a macromolecule comprising the step of adding to a crystallisation sample a mesoporous glass of the composition Si02; CaO—P205-SiO2 or Na20-CaO—P205-SiO2, wherein each of the Ca, P, Si or Na atoms within the compositions may be substituted with a suitable atom chosen from B, Al, Ti, Mg, or K, and, optionally, the composition may also include heavy elements to enhance X-ray diffraction contrast such as Ag, Au, Cr, Co, Sr, Ba, Pt, Ta or other atom with an atomic number over 20.

Abstract: This invention relates to a method and apparatus for the processing of shellfish waste meal. More particularly, to increasing the crude protein while decreasing calcium and phosphorus levels of shellfish waste meal. The method significantly reduces the percent calcium and phosphorus in shellfish waste meal by introducing a strong acid while lowering the ratio of calcium to phosphorus and raising or maintaining protein levels of the shellfish waste meal at a neutral pH level.

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: 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 method for lowering the iron content of calcium carbonate is disclosed. The method involves addition of an iron chelating agent to an aqueous calcium carbonate slurry, reducing the pH of the aqueous calcium carbonate by employing carbon dioxide containing gas, while maintaining the aqueous calcium carbonate slurry at an elevated temperature. The slurry is stirred, filtered, washed and dried. The calcium carbonate product resulting from the process of the present invention has a reduced iron content.Calcium carbonate produced according to the method of this invention is particularly suitable for use as food or pharmaceutical additives and may also be useful as a filler in papermaking processes or as additives in plastic products.

Abstract: An extremely compact, energy efficient air purifier for incinerating volatile organic chemical contaminants, and airborne organic particulates comprises a cylindrical ceramic heat transfer/storage element having many substantially identical axially parallel flow passages with very large surface area per mass, and a rotating guide for guiding the inlet air flow to a preset radial segment of the ceramic element. The air flow exiting from the preset radial segment is directed to the remaining segment in the opposite direction. The air flow exiting from the remaining segment is exhausted from the air purifier. Included is a pre-heater for heating the ceramic element at start up, and maintaining the air flow at a stable incineration temperature.

Abstract: An improved process for the production of road deicer products preferably containing calcium magnesium acetate or calcium magnesium acetate/calcium magnesium propionate is provided. The process involves first providing a residual water plant sludge starting material containing calcium and magnesium compounds, and reacting this sludge with stoichiometric quantities of at least acetic acid and more preferably both acetic and propionic acids. The resultant reaction product can then be dried, ground and granulated to provide a dry, free flowing road deicer product.

Abstract: Magnesium hydroxide of the formula Mg(OH).sub.2 having a crystallite size in the direction <004> greater than 150 .ANG. and smaller than 500 .ANG., an aspect ratio in the range from 2 to 5, a strain in the direction <004> not greater than 4.2.times.10.sup.-3 and a strain in the direction <110> not greater than 3.0.times.10.sup.-3. 50% of secondary particles with diameters smaller than 1.4 .mu.m and 100% of secondary particles with diameters not greater than 4.0 .mu.m, and a specific surface, determined by the BET method, smaller than 25 m.sup.2 /g. It is prepared by a two-step procedure; in the first step, magnesium nitrate is treated by an alkaline substance, preferably by ammonia, in an aqueous medium, with 1.5 to 6.0-multiple excess of ammonia, at a temperature of not more than 85.degree. C., at the atmospheric pressure, causing that basic magnesium nitrate is formed which, in the second step, decomposes at a temperature of 110.degree. to 150.degree. C.

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 method of improving surface morphology of a laser irradiated surface includes a first step of irradiating a pulse laser beam one or a plurality of times on a region of a conductor layer which is formed on an under layer so as to melt the entire conductor layer, and a second step of irradiating a pulse laser beam on the irradiated region of the conductor layer at least once after the first step with an energy density such that only a surface portion of the conductor layer melts in substantially the entire irradiated region.

Abstract: The invention concerns a method of bleaching particles containing calcium carbonate by keeping them in contact with an aqueous solution containing hydrogen peroxide and having a pH-value below 8.

Abstract: Fermentors, reactors and processes for preparing magnesium enriched calcium magnesium acetate (CMA) (Mg:Ca mole ratios of 1:1 to 20:1) by reacting a dolomitic lime product with a Mg:Ca mole ratio less than one with dilute acetic acid, such as in fermentation broths. A process to prepare a mildly aklaline mineral product by calcining the dolomite under conditions to convert only the MgCO.sub.3 to MgO and treating the selectively calcined dolomite with acidic solutions to dissolve largely the MgO, leaving the original CaCO.sub.3 matrix intact. The mildly alkaline mineral product includes a highly porous structure derived from dolomite, consisting of a matrix of CaCO.sub.3 with smaller amounts of MgO and interspersed with a regular array of voids on a molecular scale.

Abstract: There is disclosed a process for purifying a calcium carbonate-containing mineral which process comprises the following steps:a) mixing the calcium carbonate-containing mineral with water and a dispersing agent to form a suspension containing from 60% to 80% by weight of the dry mineral;b) comminuting the suspension of calcium carbonate-containing mineral prepared in step a) to give a product containing not more than 5% by weight of particles which are retained on a sieve having a nominal aperture of 53 microns and not more than 50% by weight of particles which are smaller than 2 microns e.s.d.

Abstract: A process for improving a purity and/or whiteness degree of a talc powder is disclosed. A talc powder with a particle size of about 0.8 mm or less containing impurities such as asbestos, etc. is treated with a phosphoric acid agent under heating at from 70.degree. to 250.degree. C. to remove impurities such as asbestos, etc. by utilizing the difference in the rate of dissolution as between the talc and the impurities. The phosphoric acid agent is one selected from the group consisting of phosphoric acid, pyrophosphoric acid, sodium phosphate, ammonium phosphate, calcium phosphate, sodium tripolyphosphate, sodium pyrophosphate, sodium hexametaphosphate and mixtures thereof. Thus, asbestos, which is considered to be carcinogenic, can be effectively removed from talc.

Abstract: Processes for the selective leaching of magnesium-containing solids, which contain calcium and/or heavy metals, and the selective precipitation and crystallization of the leached magnesium are provided. The leaching is conducted with aqueous sulphur dioxide at elevated temperatures with feed pulp densities which are sufficiently high to produce a leach liquor which is substantially saturated with magnesium. The selective crystallization and precipitation processes which preferably follow the selective leaching process, utilize controlled cooling, heating and pH conditions to yield a high purity magnesium sulphite product.

Abstract: A method of making a mortar binder including the steps of heating marine shell material to a predetermined high range of temperature, allowing the material to cool, mixing with the material a predetermined proportion of water, which may be sea water, allowing the mixture to react at a spontaneously generated temperature and allowing the mixture to cool until it converts into the binder of a homogeneous, substantially white fluffy powdery substance similar to fine ground talcum powder.

Abstract: A method for improving the brightness of limestone utilizing a chelating agent and a bleaching agent in a limestone slurry in which the pH of the slurry is normally between 9.0 and 9.6.

Abstract: A porous hydroxyl apatite material is disclosed which is made from calcium-rich basic skeletons of lime-encrusting algae converted into hydroxyl apatite and which serves for use as artificial bone, artificial tooth root, augmentation material, stabilization material, artificial hollow bodies or defect filling material.

Abstract: Finely divided lime, at any degree of slaking, is introduced in a steady stream into an agitated reactor designed to produce pellets or aggregates. Concentrated acetic acid is simultaneously introduced in a steady stream at a rate equal to the chemical combining rate required to produce calcium magnesium acetate. Water content of the reaction stream is critical; the mol ratio of water, including water of neutralization, to the calcium magnesium acetate product must fall in the range 3.3-7.0 in order to form the desired pellets and to avoid sticking, caking, and dust emanation from the reactor. Product pellets are drawn off in a stream from the reactor and dried for use as a non-polluting roadway and walkway deicer. Traction agent is optionally incorporated into the deicer pellets by introducing a steady stream of traction agent to the reactor simultaneous with raw materials introduction. Magnesium-to-calcium ratios greater than one are achieved by blending dolime with magnesium-rich ore.

Abstract: For bleaching natural chalk, an aqueous suspension consisting of 50 to 80% by weight fine-grained natural chalk and 50 to 20% by weight water and containing 0.1 to 1.5% by weight, based on the dry weight of the chalk, of a dispersant and optionally containing a hydrogen peroxide stabilizer or activator or a salt of hydrogen peroxide with a divalent metal is prepared, the suspension is wet ground to reduce the particle size until about 9/10 of the particles have a grain size of <4, the suspension is mixed with hydrogen peroxide or a salt of hydrogen peroxide with a divalent metal at temperatures between 50.degree. and 99.degree. C. and at a specific pH-value or at an alkaline pH, respectively, and stirred intensively until it is mixed and foaming commences, the suspension is allowed to stand until foam formation is complete and then the foam formed is separated with the dark particles contained therein.

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: A process for the manufacture of calcium acetate pellets suitable for surface deicing, which comprises slow addition of water to dried calcium acetate or to calcium acetate freshly prepared from reaction of hydrated or unslaked lime with concentrated acetic acid, in an agitated vessel designed to produce pellets. Pellets are dried to a critical residual water level to avoid their embrittlement. The relative amount of water used in the pelletizing process is highly critical, and depends upon the source of calcium acetate as well as the amount of magnesium ion in the pellet formulation.

Abstract: Process of purification of magnesic raw material. Sulphur dioxide is allowed to react with an aqueous suspension of calcinated magnesite, crude or contaminated magnesium oxide, magnesium hydroxide, hydrated magnesium carbonates, or crude crystals of magnesium sulphite, and, after reaching a pH of 3 to 7.5 the reaction mixture is separated into a solid phase at least one fraction of which is rich in MgSO.sub.3.xH.sub.2 O, wherein x stands for 3 or 6, and at least one fraction containing concentrated impurities. The whole process is carried out at least once. A reaction mixture having a pH below 5 can be preferably transferred to pH 5.2 by the addition of an alkali, e.g. magnesium oxide or magnesium hydroxide, whereupon separation of at least two fractions of the solid phase is accomplished. The fractions obtained can be further purified by mixing in a hydrophilic liquid, and by a following separation. The fraction of crude magnesium sulphite crystals can be heated to a temperature over 60 degress C.

Abstract: A process of making a calcium acetate-containing solution having a pH value at room temperature between about 7 and about 8 is provided comprising reacting acetic acid with a carbonate compound, adding calcined limestone, and optionally finishing off the acid-base reaction with an amount of an alkali metal hydroxide comprising from about 2% to about 5% of the total stoichiometric complement to the amount of acetic acid. Further process options which may be used in the preparation of deicing agents include adding coarse limestone to the above-prepared calcium acetate-containing solution in amounts up to 10% by weight and converting the solution into solid flakes. The calcium acetate salt product can be mixed with an inert solid material having good anti-slip properties.

Abstract: A process of reacting aqueous acetic acid and crushed raw limestone in such a way as to produce a mixture of calcium acetate, calcium acid-acetate, and unreacted raw limestone devoid of undesirable fine limestone. Such a product is useful in winter highway treatment, where the environmentally safe soluble acetates function to depress the freezing point of water, and the limestone acts as a roadway traction agent. When as much as 3 mols of acetic acid per mol of active calcium carbonate in limestone are used, all the limestone is consumed, with virtually 100% yield of calcium acid-acetate.

Abstract: A process of making a calcium acetate-containing solution having a pH value at room temperature between about 7 and about 8 is provided comprising reacting acetic acid with a carbonate compound, adding calcined limestone, and optionally finishing off the acid-base reaction with an amount of an alkali metal hydroxide comprising from about 2% to about 5% of the total stoichiometric complement to the amount of acetic acid. Further process options which may be used in the preparation of deicing agents include adding coarse limestone to the above-prepared calcium acetate-containing solution in amounts up to 10% by weight and converting the solution into solid flakes.

Abstract: A process of making different grades of calcium magnesium acetate deicing agents, having substantially uniform but different calcium-to-magnesium mole ratios, from limestone having varying proportions of calcium carbonate and magnesium carbonate, is provided wherein limestone containing calcium and magnesium carbonates is finely divided, mixed with water to form an aqueous suspension of limestone, vigorously agitated and reacted with excess acetic acid. The reaction is completed by adding to the reaction batch about 30% of the molar equivalent of calcined finely divided limestone base to produce a calcium magnesium acetate salt solution having a calcium-to-magnesium mole ratio much greater than one. The insolubles from this first reaction are removed, calcined and reacted with acetic acid in a second reaction to produce a calcium magnesium acetate salt solution having a calcium-to-magnesium mole ratio substantially equal to one.

Abstract: A process of making a calcium acetate-containing solution having a pH value at room temperature between about 7 and about 8 is provided comprising reacting acetic acid with a carbonate compound, adding calcined limestone, and optionally finishing off the acid-base reaction with an amount of an alkali metal hydroxide comprising from about 2% to about 5% of the total stoichiometric complement to the amount of acetic acid. Further process options which may be used in the preparation of deicing agents include adding coarse limestone to the above-prepared calcium acetate-containing solution in amounts up to 10% by weight and converting the solution into solid flakes.

Abstract: Method for improving the brightness of limestone utilizing a flocculating agent and a bleaching agent where the pH of the slurry is between about 7 and 9.

Abstract: A method of selectively extracting calcite and dolomite away from apatite in phosphate rock or phosphatic limestone wherein the phosphate rock or phosphatic limestone is treated with a mixture of sulfur dioxide, water, and a carbonyl compound. Solids are separated from the liquid phase. The solids consist principally of apatite admixed with clay, quartz, and other accessory minerals originally in the rock. The solids are heated to drive off adhering sulfur dioxide, water, and carbonyl. The liquid phase consists of carbonyl, water, sulfur dioxide, and magnesium and calcium ions. Heating this liquid preferentially precipitates CaSO.sub.3.1/2H.sub.2 O. This solid is filtered off and the filtrate further heated to precipitate MgSO.sub.3.3H.sub.2 O largely free of CaSO.sub.3.1/2H.sub.2 O. All off gas and filtrate is returned to the process.

Abstract: This invention is concerned with the recovery of relatively pure magnesia from magnesite which is normally contaminated with too much silica and silicates to permit the magnesite simply to be calcined for the recovery of refractory grade magnesia. The magnesite in its raw uncalcined state is treated with SO.sub.2 at elevated temperatures preferably between 50.degree. and 60.degree. C. thereby rapidly dissolving a high proportion of magnesium as bisulphite without the cost of initial calcination and without dissolving above about 1% of SiO.sub.2 present in the magnesite. The solution of magnesium bisulphite can thus be purified by filtration and magnesia may be recovered in known manner from the purified solution.

Abstract: This disclosure is concerned with the demineralization of crustacea shells and the like, before or after protein removal therefrom, with sulfurous acid, thus to convert the calcium carbonate of the shell to calcium bisulfite solution which may be separated from the solid residual shell, and regenerating sulfurous acid from the said solution for reuse in the process.

Abstract: Finely divided lime, at any degree of slaking, is introduced in a steady stream into an agitated reactor designed to produce pellets or aggregates. Concentrated acetic acid is simultaneously introduced in a steady stream at a rate equal to the chemical combining rate required to produce calcium magesium acetate. Water content of the reaction stream is critical; the mol ratio of water, including water of neutralization, to the calcium magnesium acetate product must fall in the range 3.3-7.0 in order to form the desired pellets and to avoid sticking, caking, and dust emanation from the reactor. Product pellets are drawn off in a stream from the reactor and dried for use as a non-polluting roadway and walkway deicer. Traction agent is optionally incorporated into the deicer pellets by introducing a steady stream of traction agent to the reactor simultaneous with raw materials introduction. Magnesium-to-calcium ratios greater than one are achieved by blending dolime with magnesium-rich ore.