Abstract: A method of recovering a metal from a low-grade ore which is subjected to cyanide leaching to produce a PLS which contains a metal cyanide which is removed from the PLS by ultrafiltration and nano-filtration, and then acidified and sulphidised to produce a metal sulphide from which the metal is extracted, and hydrogen cyanide which is recycled to the cyanide leaching step.

Abstract: The present invention relates to a process for reducing in a gas stream the concentration of carbon dioxide and for reducing in an aqueous stream the concentration of sodium chloride, which process comprises contacting a feed gas comprising greater than or equal to 0.1% by volume carbon dioxide with an aqueous feed comprising: (a) sodium chloride; and (b) calcium oxide and/or calcium hydroxide at a total concentration of greater than or equal to 0.5% by weight, wherein the pH of the aqueous feed is greater than or equal to 10.0. A product aqueous stream obtained from the process of the invention is also described.

Abstract: The subject of the invention is a method for reduction of the CO2 content of flue and atmospheric gases and equipment for application of the method. The characteristic of the solution according to the invention is, that “hydroxide” ionized water containing (OH?) ions of alkaline characteristics is used as reaction medium for binding carbon dioxide (CO2) gas, and carbon dioxide (CO2) gas gets into reaction with alkaline ionized water, and during the reaction from the carbon dioxide (CO2) gas and water, carbonate ion (CO32?) and hydrogencarbonate/bicarbonate (2HCO3?) are formed, and they leave for the outside atmosphere and/or outside water with the bound CO2 content in stable gas or liquid form.

Abstract: CO2-sequestering formed building materials are provided. The building materials of the invention include a composition comprising a carbonate/bicarbonate component. Additional aspects of the invention include methods of making and using the CO2-sequestering formed building material.

Abstract: A low-voltage, low-energy electrochemical system and method of removing protons and/or producing a base solution comprising hydroxide and carbonate/bicarbonate ions, utilizing carbon dioxide in a cathode compartment that is partitioned into a first cathode electrolyte compartment and a second cathode electrolyte compartment such that liquid flow between the cathode electrolyte compartments is possible, but wherein gaseous communication between the cathode electrolyte compartments is restricted. Carbon dioxide gas in one cathode electrolyte compartment is utilized with the cathode electrolyte in both compartments to produce the base solution with less that 3V applied across the electrodes.

Abstract: A method and system of separating an acid from an acid-salt solution produced in an electrochemical system using an ion exchange resin bed, by processing the acid-salt solution through the ion exchange resin bed such that the acid is retarded at the bottom of the bed and a de-acidified salt solution is recovered from the top of the bed. After removing the salt solution from the bed, the acid is recovered by back-flushing the resin bed with water.

Abstract: A low-energy electrochemical method and system of forming bicarbonate ion solutions in an electrochemical cell utilizing carbon dioxide in contact with an electrolyte contained between two ion exchange membranes in an electrochemical cell. On applying a low voltage across an anode and cathode in electrical contact with the ion exchange membranes, bicarbonate ions form in the electrolyte without forming a gas, e.g., chlorine or oxygen at the electrodes.

Abstract: Methods of sequestering carbon dioxide (CO2) are provided. Aspects of the methods include precipitating a storage stable carbon dioxide sequestering product from an alkaline-earth-metal-containing water and then disposing of the product, e.g., by placing the product in a disposal location or using the product as a component of a manufactured composition. Also provided are systems for practicing methods of the invention.

Abstract: A low-energy method and system of forming hydroxide ions in an electrochemical cell. On applying a low voltage across the anode and cathode, hydroxide ions form in the electrolyte containing the cathode, protons form at the anode but a gas e.g. chlorine or oxygen does not form at the anode.

Abstract: The present invention relates to a process for the preparation of stable iodate-exchanged hydrotalcite with zero effluent discharge. The iodate-exchanged hydrotalcite produced is useful as iodizing agent. The invention further relates to utilization of alkaline effluent generated in the process of ion exchange of iodate into SHT so as to fully recycle the residual iodate anion and also utilize the alkali generated in the process for production of additional quantities of iodate through reaction with iodine crystals followed by electrochemical oxidation to obtain pure aqueous solution of iodate salt which can be reused for preparation of the stable iodizing agent. The process gives zero effluent discharge hence economical.

Abstract: The present invention provides a process for producing fine particles of a salt, hydroxide or oxide, wherein when producing the salt, hydroxide or oxide by electrodialysis using anion exchange membranes and cation exchange membranes, a conductive liquid acting as a poor solvent for the salt, hydroxide or oxide which is produced in a concentration chamber is used as a concentration chamber solution, as well as the fine particles of the salt, hydroxide or oxide which are produced by the above process.

Abstract: A recovery method of a compact disc includes the steps of: crushing a compact disc; b) placing the crushed compact disc into a stripping solution, so that the metallic layer is separated from the plastic base plates of the crushed compact disc; c) filtering the plastic base plates from the stripping solution; d) recovering the metal; and e) recovering the plastic base plates. Thus, the waste compact disc may be recovered and reused, thereby preventing incurring an environmental pollution.

Abstract: An electrochemical process is provided for treatment of molten kraft smelt produced from black liquor in a kraft recovery boiler. Treated smelt can be contacted with water to produce white liquor which can be re-used or recycled in the kraft process.

Abstract: The present invention provides an electrochemical process for reducing metal contaminants in calcium carbonate by solubilizing the metal contaminate in an aqueous solution of calcium carbonate and then removing the solubilized metal contaminant by passing an electrical current through the aqueous calcium carbonate solution containing the solubilized metal contaminant. Calcium carbonate produced according to the process of this invention is particularly suitable for use as food or pharmaceutical additives. The calcium carbonate is also suitable for use in papermaking process as fillers, or coatings, or as additives in the production of plastics, paints and adhesive products. Other uses of high purity calcium carbonate include catalysts and catalyst supports, electrical/semiconductor applications, florescent lighting, and optical/laser applications.

Abstract: The present invention relates to processes for the production of cobalt(II) carbonates corresponding to the general formula Co[(OH)2]a[CO3]1−a, cobalt(II) carbonates and cobalt(II) oxalate carbonates obtainable by the process and the use thereof.