Abstract: A method of manufacturing colored chalk. The method for manufacturing colored chalk includes preparing a colorant, combining the colorant with a volume of water, adding magnesium carbonate to the combination of water and colorant until a paste is formed, mixing the paste until the paste is homogenous, heating the paste in a kiln until the water is removed, and grinding a mass of colored magnesium carbonate into a powder having a desired fineness. In some embodiments, the colorant includes iron oxide, charcoal, or Camellia sinensis leaves.

Abstract: The present invention provides a process for producing high purity hydromagnesite from a source of magnesium chloride. The process involves preparation of a magnesium chloride brine of a specific concentration, which is ammoniated at a specific temperature range, followed by carbonation, while maintaining the reaction at a specific temperature range to form a hydromagnesite precipitate. The product can be calcined to generate high purity magnesium oxide compounds.

Abstract: The present invention relates to a process for the preparation of a surface-reacted precipitated calcium carbonate (PCC) pigment having an insoluble, at least partially crystalline calcium salt on its surface. In the process of the present invention, a PCC containing pigment is contacted with H3O+ ions and a solubilized anion in an aqueous medium in the presence of excess solubilized calcium ions to form the surface-reacted PCC having an insoluble, at least partially crystalline calcium salt of the anion formed on its surface.

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: The present invention provides an integrated process for the recovery of sulphate of potash (SOP), ammonium sulphate and surface modified magnesium hydroxide and/or magnesium oxide utilizing kainite mixed salt and ammonia as the only consumable raw materials. The process involves treating kainite mixed salt with water to obtain solid schoenite and a schoenite end liquor. The latter is desulphated using CaCl2 generated in the process itself and thereafter evaporated to obtain carnallite crystals from which KCl is recovered while the liquor rich in MgCl2 serves as a source of MgCL. The gypsum produced during desulphatation is reacted with aqueous ammonia and CO2 to produce ammonium sulphate and calcium carbonate. The calcium carbonate so obtained is then calcined to obtained CaO and CO2. The CaO is then slaked in decarbonated water and reacted with the MgCl2-rich liquor generated above to produce slurry of Mg(OH)2 in aqueous CaCl2.

Abstract: Disclosed is a process for removing metals from waste, particularly electronic waste (or “e-waste”). The process generally includes the steps of dissolving at least some of the metals from the waste with nitric acid reagent and then causing at least some of the metals to precipitate as metal oxides and/or metal nitrates. NOx gases produced as by-product by the nitric acid dissolution of metallic components in the electronic waste are reused, in particular for generating permanganate when one of the metallic components comprises manganese.

Abstract: An improved method for processing of nickel-bearing ores, laterite ores, saprolite and limonite ores, oxidic and sulfide ores, metallurgical wastes, and other metal-bearing materials, to recover the valuable minerals contained therein, comprising comminuting ore to a desired size; leaching the ore at about 70 C to 130 C for about 30 minutes to 4 hours with nitric acid, raising the temperature of the solution to form a liquid/solid residue in which nickel, cobalt and magnesium values are in solution, and iron, manganese, and aluminum are solid residues in oxide form; conducting a liquid-solid separation and removing the solids; and recovering the nickel, cobalt, and manganese from the liquid-metal concentrate. The leachate is recovered and the nitric acid from the leachate is recycled.

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 provides an improved process for the preparation of MgO of high purity >99% from salt bitterns via intermediate formation of Mg(OH)2 obtained from the reaction of MgCl2 and lime, albeit indirectly, i.e., MgCl2 is first reacted with NH3 in aqueous medium and the slurry is then filtered with ease. The resultant NH4Cl-containing filtrate is then treated with any lime, to regenerate NH3 while the lime itself gets transformed into CaCl2 that is used for desulphatation of bittern so as to recover carnallite and thereafter MgCl2 of desired quality required in the present invention. The crude Mg(OH)2 is dried and calcined directly to produce pure MgO, taking advantage of the fact that adhering impurities in the Mg(OH)2 either volatilize away or get transformed into the desired product, i.e., MgO.

Abstract: The present invention provides an improved process for the preparation of MgO of high purity >99% from salt bitterns via intermediate formation of Mg(OH)2 obtained from the reaction of MgCl2 and lime, albeit indirectly, i.e., MgCl2 is first reacted with NH3 in aqueous medium and the slurry is then filtered with ease. The resultant NH4Cl-containing filtrate is then treated with any lime, to regenerate NH3 while the lime itself gets transformed into CaCl2 that is used for desulphatation of bittern so as to recover carnallite and thereafter MgCl2 of desired quality required in the present invention. The crude Mg(OH)2 is dried and calcined directly to produce pure MgO, taking advantage of the fact that adhering impurities in the Mg(OH)2 either volatilize away or get transformed into the desired product, i.e., MgO.

Abstract: A method of treating solid containing material derived from effluent or sludge from a plant for deinking paper, the material containing calcium in the form of one or more insoluble calcium compounds, the method including the steps of treating the material with an acid to cause dissolution of the calcium thereby forming a calcium ion-containing solution in which insoluble solids are suspended, separating the solution from the insoluble solids and incinerating the separated solids. The solution containing calcium ions may be treated by adding one or more reagents to form a calcium compound precipitate, eg calcium carbonate. The particulate solids produced following the incineration step and following the precipitate formation may be employed as pigments or fillers in paper making or paper coating.

Abstract: A process for producing potassium nitrate and other metal nitrates from the chlorides, sulfates, oxides of these metals. The process uses nitrogen dioxide as a true fluidizing medium in shallow beds of the aforementioned solids at moderately elevated temperatures in a continuous counter current process to convert the metal chlorides, sulfates, and oxides, into metal nitrates and effluent gas and water vapor. The process may be carried out in a series of true fluidized beds arranged in a vertical configuration so that the solids flow downward due to the fluidized process and the nitrogen dioxide gas flows counter currently in an upward direction producing pure metal nitrates at the bottom and nitrosyl chloride gas and/or water vapor at the top.

Abstract: A method of treating solid containing material derived from effluent or sludge from a plant for de-inking paper, the material containing calcium in the form of one or more insoluble calcium compounds, the method including the steps of treating the material with an acid to cause dissolution of the calcium thereby forming a calcium ion-containing solution in which insoluble solids are suspended, separating the solution from the insoluble solids and incinerating the separated solids. The solution containing calcium ions may be treated by adding one or more reagents to form a calcium compound precipitate, eg calcium carbonate. The particulate solids produced following the incineration step and following the precipitate formation may be employed as pigments or fillers in paper making or paper coating.

Abstract: Low-cost, high-purity strontium nitrate that is low in Ba, Na, Ca, Cr, and other impurities and that is suitable for use in airbags or the like is provided. High-purity strontium nitrate having a Ba content of 0.01 wt % or lower, an Na content of 0.005 wt % or lower, a Ca content of 0.01 wt % or lower, a Cr content of less than 0.001 wt %, and a purity of 99.5 wt % or higher is produced by a manufacturing method comprising a first step for performing crystallization by adding nitric acid to an aqueous solution obtained by dissolving a strontium compound as a starting material, a second step for separating the resulting crystals, a third step for crystallizing the resulting separated solution, and a fourth step for separating the resulting crystals.

Abstract: Method of recovering calcium carbonate from waste material or contained natural calcic material. Calcium is recovered by prepariag an aqueous suspension the material containing calcium to be recovered and by lowering the pH of the suspension to pH<6, preferably pH<4, for providing a spension including an acidic liquid phase containing the calcium compounds in soluble form. Thereafter the pH of the liquid is raised to pH>6, preferably pH>7, by mixing a base therein, for precipitating the main portion of aluminium therein. Thereafter the neutral or basic liquid phase is carbonized by introducing Na2CO3 or NaHCO3 therein, for precipitation of the calcium compounds as CaCO3.

Abstract: The present invention provides a process for preparing a flame retardant quality magnesium hydroxide which includes providing a magnesium salt solution; and a source of ammonia; adding a stochiometric excess of ammonia to the solution to form a magnesium hydroxide precipatate; and subjecting the magnesium hydroxide to a hydrothermal recrystallization.

Abstract: In a process for producing anhydrous magnesium chloride, the following combination of steps: drying impure salt containing hydrated magnesium chloride; establishing a solution of the hydrated magnesium chloride; removing insoluble impurities; reacting the solution of hydrated magnesium chloride at substantially ambient temperature and pressure by feeding it into an ammonia saturated very low boiling point alcohol solution and in the presence of ammonium chloride while maintaining the last-mentioned solution saturated in ammonia thereby to form a precipitate of ammoniated magnesium chloride; separating the precipitate and heating it to obtain anhydrous MgCl.sub.2 and ammonia for recycling.

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 electrical resistance heated oven is used to heat a crucible to melt a sample and to simultaneously heat a casting dish into which the molten sample can be poured. The oven is cooled with the crucible and casting dish within the oven in order to prepare a sample bead for analysis. In another embodiment of the invention the sample is again melted in a crucible and after melting the crucible is moved out of the oven and turned to pour the molten sample into an acid solution positioned external to the oven. The crucible and sample can be moved while in the oven to mix the sample. The method of preparing an analytical sample using the electrical resistance heated oven is also disclosed.

Abstract: The present invention relates to a method for purifying calcium nitrate melt or solution separated from the mixture obtained by dissolution of rock phosphate with nitric acid. The melt contains fluorine and phosphorus as main contaminants. The mol-ratio phosphorus/fluorine in the crude calcium nitrate melt/solution is adjusted to 3.5>P/f>0.3, possibly by extra addition of a phosphorus compound, and the mixture is then neutralized by ammonia to pH=5-6. The precipitate thereby formed is removed while the filtrate, which is a purified nitrate of lime melt, is evaporated and further processed. The purification can be carried out in two stages, with a P/F-ratio in the first stage of 0.3-3 and 1-3.5 in the second stage. Phosphoric acid or a phosphoric acid containing solution is used as phosphorus compound.

Abstract: Cadmium is removed from an acid, phosphate-containing aqueous medium with the aid of an anion exchanger, in which process, during the removal, iodide or bromide ions are present in a quantity of 100-6000 ppm calculated with respect to the acid phosphate-containing aqueous medium.

Abstract: An improved process for more economically and effectively producing crystalline by-product ammonium sulfate (A/S) by granulating crystalline by-product A/S feedstock and recycle material together with an A/S-sulfuric acid-granulation aid-particle hardener solution and ammonia to bind the crystals together. Underlying the gist of the improvement concept is the identification of a low-cost readily available lignosulfonate by-product of the pulp and paper industry which, when used in predetermined and relatively small proportions, has now been discovered to be very satisfactory as a granulation aid-particle hardener for granulating such by-product ammonium sulfate crystals. Use of lignosulfonate instead of alum, as is currently practiced, reduces the manufacturing cost of granulating by-product ammonium sulfate by about as much as one dollar per short ton of product.

Abstract: A process for granulating crystalline by-product ammonium sulfate, hereinafter referred to, for the sake of convenience, as A/S, to produce a product having excellent physical and chemical properties as they relate to the storage and handling thereof and also as they relate to the bulk blending of same with other fertilizer blend materials. The method involves introducing the crystalline by-product A/S feedstock, together with recycle material, into a conventional drum ammoniator granulator and granulating the mixture using A/S-sulfuric acid-alum solution and gaseous anhydrous ammonia to bind the crystals together by virtue of the fresh A/S produced and precipitated. Drying in a rotary drum dryer by countercurrent flow of hot gases instead of the more conventional cocurrent gas flow is required.

Abstract: A process for recovering metallic values by putting the values into solution and separating undesired mineral matter from the solution using countercurrent flotation is provided. The process involves leaching metallic values from host rock, conditioning the resultant ore pulp with the required reagents to achieve selective flotation of mineral matter in the metallic values solution, introducing the conditioned ore pulp into flotation cells, along with counterflow of solution from an immediately subsequent flotation step, wherein simultaneous washing and flotation is achieved, and the mineral matter is removed leaving a solution of the metallic values. The resultant mineral matter froth product is subjected to subsequent stages of flotation and simultaneous washing with counterflow of solution removed from each subsequent stage of flotation, water and/or barren solution being used for washing in the final flotation stage.

Abstract: Strontium carbonate is prepared by the process of reacting strontium nitrate in an aqueous reaction medium with carbon dioxide to precipitate strontium carbonate product, the nitric acid byproduct that forms being neutralized by the introduction of lime to the reaction medium.

Abstract: Strontium nitrate is prepared by reacting celestite (strontium sulfate) with excess calcium nitrate in limited amounts of water, quickly extracting strontium nitrate from the reaction mixture by vigorous agitation with additional water, and recovering strontium nitrate by evaporation of the extract solution.

Abstract: An apparatus for granulation of precipitation products, comprising a liquid-filled reaction chamber including a granulation chamber which receives aqueous streams of compounds which precipitate to form granules. The granulation chamber has an open upper edge connected to the narrow edge of a conical surface. The upper open edge of the conical surface merges with an apron which is spaced inwardly from the inner periphery of the reaction chamber. Conduit means conduct granules downwardly from the granulation chamber. Liquid and fine granules rise upwardly within the conical surface. Granules descend back into the granulating chamber. Clean liquid passes downwardly through the annular space between the apron and the reaction chamber for removal from the space between the conical surface and the apron.

Abstract: The addition of an excess of asbestos tailings in the course of the extraction of magnesium from asbestos tailings by digestion with an acid greatly facilitates the elimination of silica and other impurities by filtration of the resulting reaction mixture. The improvement reduces the filtration time and the filtration leaves a cake which is much easier to dispose.

Abstract: This invention outlines a process to beneficiate carnallite ores in such a way as to obtain anhydrous MgCl.sub.2 of sufficient purity to be used as feed for an electrolysis cell producing magnesium metal. Commercially acceptable potassium chloride as also recovered. The organic solvents and the anhydrous ammonia used to obtain the beneficiation of these carnallite materials are recovered for recycle in the process.

Abstract: A process for the preparation of magnesium compounds from breunnerite or from mineral concentrates or tailings containing breunnerite in which the mineral is calcined and treated with an acid and the magnesium salt solution so formed is separated from insoluble matter.

Abstract: Radiation-contaminated ammonium nitrate is heated in solution to about 100.degree. C. in the presence of finely powdered calcium oxide or lithium hydroxide. Ammonia and water vapor are given off leaving an alkaline or alkaline earth nitrate which can then be safely decomposed by calcination into a metal oxide and oxides of nitrogen. The metal oxide can be recycled in a continuation of the process. The oxides of nitrogen can be passed through water to produce nitric acid useable in dissolving oxides of fissionable materials and the ammonia may be used in aqueous solution to react with nitrates of nuclear fuel or breeder metals in the very process that produces the by-product ammonium nitrate. Thus, all by-products and reagents can be reconverted and recycled.