Abstract: A hydrometallurgical process is provided for leaching nickeliferous laterite ores at temperatures below the boiling point of the pulp and at atmospheric pressure. The high iron fraction of the laterite, referred to as limonite, is first contacted with concentrated sulfuric acid to partially or completely dissolve the iron and nickel into solution. A reducing agent is used to keep the redox potential in solution below 1000 mV to enhance cobalt dissolution and more advantageously between 1000 and 900 mV to avoid reduction of ferric iron. Further mixing of the leach slurry in the presence of sodium, potassium, or ammonium allows formation of iron jarosite at ambient pressure. The resulting acid from iron hydrolysis is neutralized with the low iron fraction of the laterite ore (saprolite), thereby dissolving nickel into solution. The resulting final leach slurry can then be treated with conventional methods to recover nickel and cobalt from solution.

Abstract: A process for leaching an ore that contains nickel and magnesium includes mixing a microorganism that is capable of producing an organic acid, a nutrient, and an ore that contains nickel and magnesium for a period of time to dissolve the nickel and form a solution containing a nickel salt and a magnesium salt, separating the nickel from the magnesium in the salt solution.

Abstract: A bio-leaching method is provided for recovering metal from a metal containing ore. The ore is subjected to contact with a microorganism selective to the oxidation of sulfur. A sulfur containing compound is mixed with the microorganism before, during or after contact with the ore to systemically form sulfuric acid to leach the metal from the ore. The ore is in the form of a slurry, a heap, a charge in a vat and is bioleached for a time sufficient to dissolve the metal in the ore and form a metal-rich leachate and an ore residue. The metal can then be extracted from the metal-rich leachate. The metal containing ore may contain base metals, precious metals, or platinum group metals. Upon formation of the metal-rich leachate, the ore residue may be further processed to recover any precious metals or platinum group metals that may be present.

Abstract: A process is provided for the leaching of both the “limonite” (Fe approx. ≧25% and Mg approx. ≧6%) and “saprolite” (Fe approx. ≦20% and Mg approx. ≧10%) fractions of typical nickel and cobalt bearing laterite ore. The low magnesium fraction of the laterite ore is leached with sulfuric acid at high pressure and temperature to solubilize the metal values while precipitating most of the solubilized iron as hematite or other iron compounds and a portion of the dissolved aluminum as alunite or other aluminum compounds. After reducing the pressure of the leach slurry to approximately atmospheric pressure, the pregnant leach slurry or solution is contacted with the high magnesium fraction of the ore to solubilize most of the nickel contained in the high-magnesium ore fraction while dissolving only a small portion of the iron content of the high magnesium ore fraction.

Abstract: A process is provided for the direct recovery of nickel and cobalt from a nickeliferous oxide ore leach slurry by ion exchange. A nickeliferous ore is leached with mineral acid to solubilize the metals. The resulting leach slurry is contacted with ion exchange resin, which selectively loads the nickel and cobalt from the pulp. The resin is separated from the leach slurry by screening and then stripped with an acidic solution. After stripping, the resin is returned to the loading cycle. Nickel and/or cobalt can be recovered in substantially pure form from the eluate by known processes. The metal-depleted slurry proceeds to waste treatment and disposal. This process eliminates the difficult solid/liquid separation, which would otherwise be required to recover metals values from the pregnant leach slurry.

Abstract: Raw lead to be refined is leached in a leach apparatus with a leach solution containing fluoro compounds. During the leaching step, lead is dissolved, with ferric fluro compounds being reduced to ferrous fluro compounds. The leaching solution resulting from the leaching step is sent to the cathodic compartment of a diaphragm cell in which lead is deposited on a cathode, in compact, highly pure form. The solution that is depleted of lead is sent to the anodic compartment in which a suitable anode oxidizes the ferrous fluro compound to ferric fluro compounds that can be recycled to the leaching step.

Abstract: A process is provided for heap leaching ore to recover nickel. The process is particularly effective for ores that have a tangible clay component (i.e., greater than about 10% by weight). The process includes sizing the ore (where necessary), forming pellets by contacting ore with a lixiviant and agglomerating. The pellets are formed into a heap and leached with sulfuric acid to extract the metal values, including nickel. The leachate may be subjected to a nickel recovery operation without the need for intermediate neutralization.

Abstract: A process is provided for leaching nickeliferous laterite ores by hydrometallurgical methods at temperatures below the boiling point of the pulp and at atmospheric pressure from which high overall nickel and cobalt extractions are obtained. The high iron fraction of the laterite, referred to as limonite, is first contacted with a concentrated mineral acid to partially or completely dissolve the iron and nickel in solution. During this process, a reducing agent is used to keep the redox potential in solution below 1000 mV to enhance cobalt dissolution and more advantageously between 1000 and 900 mV to avoid reduction of ferric iron. Further mixing of the leach slurry in the presence of sodium, potassium, or ammonium will allow the formation of iron jarosite at ambient pressure. The resulting acid from iron hydrolysis is neutralized with the low iron fraction of the laterite ore (saprolite) dissolving nickel into solution.

Abstract: A system for managing large quantities of business related documents stored electronically requires little or no reliance on the corresponding hardcopy versions. The management system data includes a processing approach that allows for the creation of documents electronically, i.e., by virtual documents the system users in concert with their everyday business activities--thus overcoming the previous difficulty in implementing paperless office environments. In particular, essentially all documents are stored as system available image files on a central image server. Organization of these image based virtual documents are created during initial document review by the users having review responsibilities in the first instance. During the review process, the system provides a highly intelligent user interface which permits the creation of indexing values corresponding to the document in a highly simplified and intuitive manner.

Abstract: A process for the biological treatment of bitumen froth tailings produced from a tar sands treatment and bitumen froth extraction process is disclosed. In this process bitumen froth tailings, containing native hydrocarbon metabolizing microorganisms, are mixed with a growth media to form an inoculum which is then incubated under isothermal conditions for an amount of time to produce a mixed bacterial culture containing bioliquor and a water product containing a reduced amount of asphaltenes as well as solids such as clays and sands. The bioliquor produced in this process is then utilized in the initial tar sands conditioning process from which bitumen froth is produced as well as in the initial tar sands mining process via bioliquor injection directly into the tar sands formation. Because the mixed bacterial culture is made up of a number of hydrocarbon metabolizing microorganisms, the bioliquor is also used in the degradation of the asphaltenes.

Abstract: A process for the extraction of bitumen from bitumen froth generated from tar sands is presented. In this process bitumen froth, extracted from tar sands using a water process not requiring the use of caustic soda, is treated in a counter-current decantation circuit with a paraffinic solvent to remove precipitated asphaltenes, water, and solids from the bitumen froth. The instant invention produces a dilute bitumen product having final water and solids content of about 0.01 to about 1.00% by weight rendering the dilute bitumen product amenable to direct hydrocracking. This process provides an alternative route to the conventional process utilizing centrifuges to separate bitumen from precipitated asphaltenes, water, and solids thereby avoiding the high capital and operating costs associated with the conventional bitumen froth treatment by centrifugation.

Abstract: A process for the extraction of bitumen from bitumen froth generated from tar sands is disclosed. In this process, bitumen froth is extracted from tar sands using a water process without requiring the use of caustic soda. The froth is treated in a counter-current decantation circuit with a paraffinic solvent to remove precipitated asphaltenes, water, and solids from the bitumen froth. A dilute bitumen product is produced having final water and solids contents of about 0.01 to about 1% by weight. This renders the dilute bitumen product amenable to direct hydrocracking. The process provides an alternative route to the conventional process of utilizing centrifuges to separate bitumen from precipitated asphaltenes, water, and solids and thus avoids the high capital and operating costs associated with the conventional bitumen froth treatment by centrifugation. The invention utilizes bitumen froth produced from a water process in which the use of caustic soda is not required.

Abstract: A bioleaching method is provided for recovering nickel from an ore selected from the group consisting nickel-containing lateritic ores and nickel-containing sulfidic ores or concentrates thereof. Where the ore selected is a nickel-containing lateritic ore, at least one micro-organism selective to the leaching of the lateritic ore is provided as an aqueous solution thereof maintained at a pH ranging from about 1 to 3 including a nutrient for the micro-organism. The ore may be in the form of a heap, or a charge in a vat, or as a slurry. Where the ore selected is a nickel-containing sulfidic ore or concentrate thereof, at least one micro-organism comprising a biooxidizing bacterium selective to the leaching of sulfidic ore is added as an aqueous solution to the sulfidic ore or concentrate maintained at a pH of about 1 to 3, including a nutrient for the bacterium.

Abstract: A method is provided for recovering nickel from high magnesium-containing lateritic ores which also contain iron. The ores which are referred to as saprolitic ores are subjected to leaching with a mineral acid from the group consisting of HCl, H.sub.2 SO.sub.4 and HNO.sub.3, HCl being preferred.Following leaching with HCl, for example, the pregnant solution obtained is separated from undissolved solids and the nickel preferably recovered by contacting the solution with a resin selective to nickel absorption. The raffinate remaining which contains iron and magnesium chlorides may be subjected to pyro-hydrolysis to produce their respective oxides and free HCl for recycle into the leaching system. The nickel is extracted from the resin using a stripping solution of said acid, and the nickel thereafter extracted from the nickel-loaded stripping solution.

Abstract: A hydrometallurgical process for producing zinc oxide from an aqueous solution containing zinc ions is provided. The process comprises the steps of contacting a zinc solution with an insoluble organic solvent selective to the extraction of zinc and thereby produce a zinc-loaded organic solvent. The zinc is then stripped from the zinc-loaded organic solvent with a solution of nitric acid to form a solution of zinc nitrate. The zinc nitrate solution is subjected to thermal hydrolysis at an elevated temperature in the presence of pressurized water vapor, the temperature being at least sufficient to decompose the zinc nitrate to zinc oxide which is thereafter recovered.

Abstract: A process is provided for separating minerals from a mixture of minerals having different densities. The minerals are provided in the comminuted state to liberate the minerals one from the other, following which the minerals are slurried in an aqueous solution of lithium metatungstate selected to provide a density between the densities of the minerals to be separated, whereby the minerals having a density greater than that of the solution will sink and the minerals having a density less than that of the solution will float.

Abstract: A method is provided for the dissolution of at least one precious metal selected from the group consisting of platinum group metals, gold and silver. The method comprises subjecting a material containing at least one of the precious metals to dissolution with a sulfuric acid solution maintained at a pH at least sufficient to complex the precious metal with bromide ions in the presence of an oxidizing agent, the amount of bromide ions in the solution being at least sufficient to form a soluble complex of the precious metal. The amount of oxidizing agent is at least sufficient to maintain a redox potential at least high enough to convert the precious metal to an ionic form conducive to forming a soluble bromide complex thereof.

Abstract: A method is provided for recovering at least one platinum group metal from an ore containing the same. The method comprises reducing the particle size of the ore to provide the platinum group metal in a leachable condition following which the ore is subjected to leaching with a sulfuric acid solution maintained at a pH of less than 1 during leaching. The solution contains an amount of a soluble bromide compound at least sufficient to complex the platinum group metal while maintaining an amount of an oxidizing agent dissolved in the solutions at least sufficient to maintain the platinum group metal in an ionic form conducive to forming a soluble bromide complex, thereby dissolving substantial amounts of the platinum group metal.

Abstract: Geothermal brines are passed through a bed of an anionic resin selective to the removal of boron while maintaining a pH value between about 4 to 5.5 to load the boron on the resin from which the boron is thereafter recovered. If the brine contains large quantities of constituents have Lewis acidities greater than boric acid, these constituents are preferably removed before the boron is recovered. The invention is particularly applicable to geothermal brines of temperature above ambient, e.g., 90.degree. C. and above, such as 95.degree. C. and above.

Abstract: A process is provided for the recovery of substantially pure zinc from geothermal brine also containing recoverable amounts of lead and silver. The process comprises selectively extracting lead and silver from the brine and then contacting the brine impoverished in lead and silver with a substantially insoluble organic extractant (e.g., an ion exchange resin [IX] or an organic solvent [SX]) selective to the extraction of zinc to produce a spent brine, and a zinc-loaded organic extractant. The zinc-loaded organic extractant is separated from the spent brine and the zinc-loaded extractant is contacted with an aqueous solution to remove the zinc as an aqueous zinc chloride solution. The pH of the zinc solution is adjusted, if necessary, to a level to condition the solution to promote the extraction thereof by a cationic organic solvent.