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: The invention provides processes and materials for phytoremediating materials which has been contaminated with arsenic, phosphorous, or other metals. In a preferred embodiment, the subject invention provides fern plants, which accumulate arsenic from contaminated materials. The fern plants efficiently remove arsenic from the materials. The fern plants can be harvested and readily disposed of, or can be treated to recover arsenic.

Abstract: The subject invention provides materials and methods for remediating soil and/or water which has been contaminated with arsenic, phosphorous, or other metals. In a preferred embodiment, the subject invention provides fern plants which accumulate arsenic from contaminated soils. The fern plants efficiently remove arsenic from the soil. The fern plants can be harvested and readily disposed of, or can be treated to recover arsenic.

Abstract: The process of the present invention “jump starts” heap biooxidation of sulfides by incorporating a previously biooxidized material into the heap. The process can be used to recover precious and/or base metals from sulfidic ores and concentrate.

Abstract: A process for removal of metal ions from soil and methods for effecting such removal are described. The process is based on manipulating the growth of crop and crop-related members of the plant family Brassicaceae in metal-containing soils so that the metal in the soils is made more available to the plants. These particular plants will absorb metals into their roots making the metals non-leachable from the soils or will absorb the metal into their roots and transfer them to the shoots and/or roots which can be easily harvested.

Abstract: A method of biotreating a solid material to remove an undesired compound using a nonstirred surface bioreactor is provided. According to the method the surface of a plurality of coarse substrates is coated with a solid material to be biotreated to form a plurality of coated coarse substrates. The coarse substrates have a particle size greater than about 0.3 cm and the solid material to be biotreated has a particle size less than about 250 .mu.m. A nonstirred surface reactor is then formed by stacking the plurality of coated coarse substrates into a heap or placing the plurality of coated coarse substrates into a tank so that the void volume of the reactor is greater than or equal to about 25%. The reactor is inoculated with a microorganism capable of degrading the undesired compound in the solid material, and the solid material is then biotreated in the surface bioreactor until the undesired compound in the solid material is degraded to a desired concentration.

Abstract: A method and apparatus for solar heating a leach solution prior to its distribution over an ore heap. The apparatus includes a distribution mat having a series of individual emitter tubes joined by heat absorbing panels. The heat absorbing panels collect and transfer the absorbed solar energy to the leach solution passing through the emitter tubes. The temperature of the leach solution passing through the emitter tubes is elevated above ambient prior to the leach solution percolating down through the ore heap. The distribution mat formed by the plurality of emitter tubes and heat absorbing panels is formed from a flexible material, thereby allowing the distribution mat to be rolled and unrolled during application to the ore heap.

Abstract: A method of recovering precious metal values from refractory sulfide ores is provided. The method includes the steps of separating clays and fines from a crushed refractory sulfide ore, forming a heap from the refractory sulfide ore, producing a concentrate of refractory sulfide minerals from the separated fines and adding the concentrate to the heap, bioleaching the heap to thereby oxidize iron sulfides contained therein, and hydrometallurgically treating the bioleached ore to recover precious metal values contained therein.

Abstract: The present invention relates to a method of remediating soil, water, and other porous media contaminated with organic and/or inorganic contaminants using plants in conjunction with an electric field applied through the medium to control movement of the contaminants and enhance removal of the contaminants from the medium. Applying an electric field in soil induces electromigration (movement of ions in the pore fluid), as well as electroosmosis (movement of pore water) and electrophoresis (movement of charged particles in soil such as colloids). In the present invention these phenomena are beneficially utilized to control the transport of charged and/or non-charged contaminants in soil within the plant root zone (rhizosphere) and to bring contaminants into the root zone, perhaps from a contaminated zone located deeper in the soil than the root zone. The effectiveness of the phytoremediation is also enhanced by preventing the soil from becoming so strongly acidic or basic as to kill the plants.

Abstract: According to the process, a heap preferably having dimensions of at least 2.5 m high and 5 m wide is constructed with chalcopyrite bearing ore. The constructed heap includes exposed sulfide mineral particles at least 25 weight % of which are chalcopyrite. The concentration of the exposed sulfide mineral particles in the heap is such that the heap includes at least 10 Kg of exposed sulfide sulfur per tonne of solids in the heap. Furthermore, at least 50% of the total copper in the heap is in the form of chalcopyrite. A substantial portion of the heap is then heated to a temperature of at least 50.degree. C. The heap is inoculated, with a culture including at least one strain of thermophilic microorganisms capable of bioleaching sulfide minerals at a temperature above 50.degree. C. A process leach solution that includes sulfuric acid and ferric iron is applied to the heap.

Abstract: A method of biooxidizing sulfide minerals in a nonstirred bioreactor is provided. According to the disclosed method, a concentrate of sulfide minerals is coated onto a plurality of substrates, such as coarse ore particles, lava rock, gravel or rock containing a small amount of mineral carbonate as a source of CO.sub.2 for the biooxidizing bacteria. After the sulfide minerals are coated or spread onto the plurality of substrates, a heap is formed with the coated substrates or the coated substrates are placed within a tank. The sulfide minerals on the surface of the plurality of coated substrates are then biooxidized to liberate the metal value of interest. Depending on the particular ore deposit being mined, the sulfide mineral concentrates used in the process may comprise sulfide concentrates from precious metal bearing refractory sulfide ores or they may comprise sulfide concentrates from metal sulfide type ores, such as chalcopyrite, pyrite or sphalorite.

Abstract: A metal-containing refractory ore, such as refractory sulfide ore, is split into a first portion and a second portion. The first portion is partially biodigested by a sulfide-digesting microorganism in a biooxidation reactor where the microorganism is acclimated to the sulfide "diet" provided by the ore. The partially digested ore is then combined with the second portion. The resulting material is then dewatered, agglomerated, biooxidized and subjected to a lixiviation process.

Abstract: A method for improving the heap biooxidation rate of refractory sulfide ore particles that are at least partially biooxidized using a recycled bioleachate off solution is provided.

Abstract: A method of biooxidizing sulfide minerals in a nonstirred bioreactor is provided. According to the disclosed method, a concentrate of sulfide minerals is coated onto a substrate, such as coarse ore particles, lava rock, gravel or rock containing mineral carbonate as a source of CO.sub.2 for the biooxidizing bacteria. After the sulfide minerals are coated onto the substrate, a heap is formed with the coated substrates or the coated substrates are placed within a tank. The sulfide minerals are then biooxidized to liberate the metal value of interest. Depending on the particular ore deposit being mined, the sulfide mineral concentrates used in the process may comprise sulfide concentrates from precious metal bearing refractory sulfide ores or they may comprise sulfide concentrates from metal sulfide type ores, such as chalcopyrite, millerite or sphalorite.

Abstract: An apparatus for applying a leaching solution to a mass of ore includes a plurality of first tubes which are connected to a supply of leaching solution. Each of the first tubes is fitted with emitters which are positioned at spaced intervals along the length of each first tube. The first tubes are connected with a manifold on their distal ends. A second tube is connected to the manifold. The second tube is fitted with a sprinkler which is positioned to distribute leaching solution over the surface area of the ore mass which is positioned intermediate adjacent emitters.

Abstract: The present invention is directed to a method for separating the group III element component of a group III-V material from an aqueous waste containing a group III-V material to allow for their recovery and beneficial use. The method includes adjusting the pH of an aqueous waste containing a group III-V material to a pH from about 9.5 to about 12.5 by adding an alkali metal hydroxide base to the aqueous waste; precipitating a group V element oxyanion by adding a soluble alkaline metal salt to the aqueous waste; separating the group V element oxyanion from the aqueous waste; adjusting the pH of the aqueous waste to form a group III element hydroxide precipitate by adding a mineral acid to the aqueous waste; separating the group III element hydroxide precipitate from the aqueous waste; and recovering the group III element from the group III element hydroxide precipitate.

Abstract: Nickel/cobalt, as well as platinum and palladium metal family members are recovered from soil by growing Brassicaceae plants, specifically Alyssum in soil containing nickel/cobalt as well as other metals. The soil is conditioned by maintaining a low pH, low calcium concentration, and the addition of ammonium fertilizer and chelating agents thereto. Nickel accumulation on the order of 2.5 percent or better in above-ground tissues is achieved, which permits recovery of the metal by harvesting the above-ground plant materials, drying, and then combusting the same, to oxidize or vaporize organic materials and recover the metals sequestered therein at 10-20 fold higher concentrations than in the soil, in a form which can be used in conventional Ni refinery or smelting operations.

Abstract: The present invention provides a method for remediating soil contaminated with Cr(VI) by reducing the Cr(VI) to Cr(III) in the soil. The method involves contacting the contaminated soil with a plant that accomplishes the reduction. Removal of the plant from the environment is not required; in fact, preferred embodiments of the invention involve plowing the plant back into the soil environment and replanting the soil.

Abstract: A method of processing a copper mineral, the method comprising activating the copper mineral by milling the copper mineral to P80 of between 2 and 20 micron, and subsequently subjecting the activated copper mineral to an oxidative hydrometallurgical treatment in the presence of chloride ions in an amount of from 2 to 10 g/L.

Abstract: The present invention provides methods by which hyperaccumulation of metals in plant shoots is induced by exposure to inducing agents. Hyperaccumulation occurs as part of a two-step process in which metals are first accumulated into plant roots; subsequent transport to plant shoots is induced by exposure to the agent. In preferred embodiments, manipulations that increase availability of metals to the plant are employed prior to application of the inducing agent. Effective inducing agents include conditions of low pH, chelators, herbicides, and high levels of heavy metals. Other phytotoxic agents are also useful. Application of multiple inducing agents results in synergistic effects.

Abstract: A method and apparatus for anaerobic oxidation of metal sulfides in ores and concentrates. Base-metal and precious-metal ores and concentrates often contain metal sulfides, such iron sulfides (e.g., pyrite, pyrhotite, arsenopyrite, etc.), copper sulfides (e.g., chalcopyrite, chalcocite, etc.), zinc sulfides (e.g., sphalerite, etc.) and/or lead sulfides (e.g., galena, etc.) and/or other metal sulfides), that must be oxidized in order to recover metal values (e.g., gold, silver, or platinum group elements) from the ores. In the present invention, these metal sulfides are oxidized in one reactor under anaerobic or anoxic conditions using oxidized metal ions, such as ferrous ions (Fe.sup.+3), as the oxidizing agent. Anaerobic oxidation of elemental sulfur that is produced by metal sulfide oxidation is biocatalyzed by sulfur-oxidizing bacteria, such as Thiobacillus ferrooxidans, Thiobacillus thiooxidans, or or Sulfolobus sp.

Abstract: A metal-containing refractory sulfide ore is split into a first portion and a second portion. The first portion is partially biodigested by a sulfide-digesting microorganism in a biooxidation reactor where the microorganism is acclimated to the sulfide "diet" provided by the ore. The partially digested ore is then combined with the second portion. The resulting material is then dewatered, biooxidized and subjected to a lixiviation process.

Abstract: A hydrometallurgical process for treating copper feed materials containing gold and/or silver by simultaneously leaching copper, gold and/or silver into an aqueous cyanide solution, extracting copper, gold and cyanide with anion exchange resin is provided.

Abstract: A method of recovering precious metal values from refractory sulfide ores is provided. The method includes the steps of separating clays and fines from a crushed refractory sulfide ore, forming a heap from the refractory sulfide ore, bioleaching the heap to thereby oxidize iron sulfides contained therein, and hydrometullurgically treating the bioleached ore to recover the precious metal values. If sufficient quantity of precious metal values are contained in the separated clays and fines, these materials can be further processed to recover the precious metal values contained therein.

Abstract: A process for removal of metal ions from soil and methods for effecting such removal are described. The process is based on manipulating the growth of crop and crop-related members of the plant family Brassicaceae in metal-containing soils so that the metal in the soils is made more available to the plants. These particular plants will absorb metals into their roots making the metals non-leachable from the soils or will absorb the metal into their roots and transfer them to the shoots and/or roots which can be easily harvested.

Abstract: A method for improving the heap biooxidation rate of refractory sulfide ore particles that are at least partially biooxidized using a recycled bioleachate off solution is provided.

Abstract: A method of biotreating a solid material to remove an undesired compound using a nonstirred surface bioreactor is provided. According to the method the surface of a plurality of coarse substrates is coated with a solid material to be biotreated to form a plurality of coated coarse substrates. The coarse substrates have a particle size greater than about 0.3 cm and the solid material to be biotreated has a particle size less than about 250 .mu.m. A nonstirred surface reactor is then formed by stacking the plurality of coated coarse substrates into a heap or placing the plurality of coated coarse substrates into a tank so that the void volume of the reactor is greater than or equal to about 25%. The reactor is inoculated with a microorganism capable of degrading the undesired compound in the solid material, and the solid material is then biotreated in the surface bioreactor until the undesired compound in the solid material is degraded to a desired concentration.

Abstract: Nickel/cobalt, as well as platinum and palladium metal family members are recovered from soil by growing Brassicaceae plants, specifically Alyssum in soil containing nickel/cobalt as well as other metals. The soil is conditioned by maintaining a low pH, low calcium concentration, and the addition of ammonium fertilizer and chelating agents thereto. Nickel accumulation on the order of 2.5 percent or better in above-ground tissues is achieved, which permits recovery of the metal by harvesting the above-ground plant materials, drying, and then combusting the same, to oxidize or vaporize organic materials and recover the metals sequestered therein at 10-20 fold higher concentrations than in the soil, in a form which can be used in conventional Ni refinery or smelting operations.

Abstract: A method for concurrently transporting and leaching metal values from an ore or concentrate containing said metal values from an originating site such as an elevated site to a delivery site comprising the steps of crushing and/or grinding the ore or concentrate to form a particulate having a size range suitable for transport by gravity or a combination of pumping and gravity as a solid constituent in an aqueous slurry, forming an aqueous slurry of from about 30 to about 70 percent by weight of said particulate in an aqueous medium, and adjusting said aqueous slurry to contain an effective amount of a lixiviant for dissolution of said metal values into the aqueous medium.

Abstract: A method for improving the heap biooxidation rate of refractory sulfide ore particles that are at least partially biooxidized using a recycled bioleachate off solution is provided.

Abstract: Metallic forms of gold and other precious metals can be dissolved and transported (mined) using an aqueous sulfide-bearing leach solution. Maximum sulfur fugacities are achieved in sulfide-bearing solutions under approximately neutral pH and relatively reducing conditions. The optimum chemical conditions are achieved specifically by heating an aqueous sulfide solution such as NaHS, Na.sub.2 S, H.sub.2 S, (NH).sub.4 S, or other suitable forms to temperatures of at least about 100.degree. C. in the presence of excess elemental sulfur. The sulfide dissociates in the solution to form aqueous sulfide species including polysulfide and HS.sup.- which lixivate gold and other precious metals.

Abstract: A method of recovering precious metal values from refractory sulfide ores is provided. The method includes the steps of separating clays and fines from a crushed refractory sulfide ore, forming a heap from the refractory sulfide ore, producing a concentrate of refractory sulfide minerals from the separated fines and adding the concentrate to the heap, bioleaching the heap to thereby oxidize iron sulfides contained therein, and hydrometallurgically treating the bioleached ore to recover precious metal values contained therein.

Abstract: A method and apparatus for extraction of precious metals from their ores and the product thereof. Oxidized ore comprising a precious metal is exposed to a leaching solution (lixiviant) comprising a relatively high concentration (fugacity) of dissolved hydrogen sulfide gas, a relatively high concentration (activity) of bisulfide ions, and a relatively low concentration (fugacity) of dissolved hydrogen gas. The hydrogen sulfide gas and bisulfide ions are preferably added to the solution by sulfate-reducing bacteria growing in a medium comprising dissolved sulfate ions and dissolved nitrate ions, but abiotic sources may also be used. Examples of such bacteria include mesophilic, fresh-water species such as Desulfobacterium catecholicum DSM 3882 and Desulfovibrio simplex DSM 4141; mesophilic, salt-water species such as Desulfovibrio salexigens DSM 2638; and thermophilic, fresh-water species such as Desulfomaculum kuznetsovii VKM B-1805. The complexed precious metal is recovered from the lixiviant.

Abstract: A process is disclosed for removing impurity elements, such as arsenic, and if necessary antimony, iron or bismuth, from valuable metal containing, such as copper containing, strongly mineral acid solutions by way of solvent extraction with organic solutions of hydroxamic acids, and for selectively stripping the impurity elements therefrom. Antimony, iron or bismuth are stripped with complexing acids, and arsenic is stripped with an aqueous solution containing valuable metal ions at a pH value in the 1.5 to 5 range, a higher pH than the original valuable metal containing aqueous acid solution.

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 of recovering precious metal values from refractory sulfide ores is provided. The method includes the steps of separating clays and fines from a crushed refractory sulfide ore, forming a heap from the refractory sulfide ore, bioleaching the heap to thereby oxidize iron sulfides contained therein, and hydrometullurgically treating the bioleached ore to recover the precious metal values. If sufficient quantity of precious metal values are contained in the separated clays and fines, these materials can be further processed to recover the precious metal values contained therein.

Abstract: A method of recovering precious metal values from refractory sulfide ores is provided. The method includes the steps of separating clays and fines from a crushed refractory sulfide ore, forming a heap from the refractory sulfide ore, producing a concentrate of refractory sulfide minerals from the separated fines and adding the concentrate to the heap, bioleaching the heap to thereby oxidize iron sulfides contained therein, and hydrometallurgically treating the bioleached ore to recover precious metal values contained therein.

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 recovering copper from copper bearing ores or fractions, by a process of first wetting and sulfatizing the ore with controlled amounts of H.sub.2 SO.sub.4 and water, followed by acid curing and repulping to sulfatize a substantial portion of the copper in the ore. Also, the fine and coarse fractions can be classified, followed by pile leaching the coarse fraction, preferably reusing the cycled H.sub.2 SO.sub.4 solution obtained during the copper recovery process. Since the coarse fraction is classified from the fine fraction, the pile leaching process is performed at very high specific flows, which substantially reduces the leaching period as compared with that of conventional pile leaching.

Abstract: A process is described for solubilizing lead contained in ores mineralized with sulphidic minerals by in-situ leaching with an acetic acid and acetate containing solution in presence of an oxidant. The in-situ leaching is conducted by means of drillholes in the ore body. In another embodiment the acetic acid and acetate containing solution is percolated through a bed of crushed untreated rock or unconsolidated mineral particles, mill tailings and/or agglomerated or unagglomerated sulphidic lead containing waste material, forming a pile or a layer in an open vat, in presence of an oxidant. Lead is recovered from the pregnant lead acetate containing solution and the solution may subsequently be recycled to further leaching of lead sulphidic minerals or lead sulphide containing particles.

Abstract: A system and method for recovering metal contaminants from soil, including a leaching subsystem and a metal recovery system.

Abstract: A process for removing dissolved oils and greases from an aqueous solution which also may contain dissolved heavy metals is provided wherein the aqueous solution is mixed with a source of ferrous ion and dithionite ion in a first step at acidic pH to reduce and permit removal of solid heavy metal, is present and to separate oils and greases from the aqueous solution. Solution from the first step if reacted in a second step with hydroxide slurries obtained from third and fourth steps. A second step solution from the second step is reacted in a third step with an alkali composition and a third solution. Optionally, the third solution is reacted with a chelating agent for iron and an oxidizer in a fourth step. A solution of chelated iron from the fourth step, when practical is disposed of. Oils and greases are recovered from the first step such as by skimming.

Abstract: This invention is directed to a process for making copper metal powder from copper-bearing material, comprising: (A) contacting said copper-bearing material with an effective amount of at least one aqueous leaching solution to dissolve copper ions in said leaching solution and form a copper-rich aqueous leaching solution; (B) contacting said copper-rich aqueous leaching solution with an effective amount of at least one water-insoluble extractant to transfer copper ions from said copper-rich aqueous leaching solution to said extractant to form a copper-rich extractant and a copper-depleted aqueous leaching solution, said extractant comprising (i) at least one oxime characterized by a hydrocarbon linkage with at least one --OH group and at least one .dbd.

Abstract: NORMs are inhibited or prevented from precipitating with scale produced by a hot aqueous solution by adding multiple portions of a crystal structure modifier to the aqueous solution as it cools before and during removal of silicon containing components by precipitation. Preferred crystal structure modifiers include polyacrylate crystal structure modifiers and phosphonomethylated amines.

Abstract: Heavy metal ions react with ferrous dithionite in acidic aqueous solution. They are reduced to metallic particles that are suitable for recycling and reuse when recovered from the acidic water. Chelating agents that are present are deactivated by bonding to the ferrous ions. Ferrous dithionite, (FeS.sub.2 O.sub.4) is either generated in-situ or ferrous ions and dithionite ions can be provided by other methods. An alkali metal hydroxide is utilized to precipitate remaining heavy metal ions including ferrous and ferric ions.

Abstract: A method of removal of valuable minerals of oil sand tailings including continuous operation of mixing said tailings with acid, curing the agglomeration and leaching of the cured agglomeration for removal of valuable minerals.

Abstract: A hydrometallurgical process for recovering copper from copper bearing ores or fractions, by a process of first wetting and sulfatizing the ore with controlled amounts of H.sub.2 SO.sub.4 and water, followed by acid curing and repulping to sulfatize a substantial portion of the copper in the ore. Also, the fine and coarse fractions can be classified, followed by pile leaching the coarse fraction, preferably reusing the cycled H.sub.2 SO.sub.4 solution obtained during the copper recovery process. Since the coarse fraction is classified from the fine fraction, the pile leaching process is performed at very high specific flows, which substantially reduces the leaching period as compared with that of conventional pile leaching.

Abstract: A process for removing dissolved heavy metal from an aqueous solution is provided where the aqueous solution is mixed with a source of ferrous ion and dithionite ion in a first step at acidic pH to reduce and permit removal of the heavy metal. Solution from the first step is reacted in a second step with hydroxide slurrys obtained from third and fourth steps. A second solution from the second step is reacted in a third step with an alkali composition and a third solution. The third solution is reacted with a chelating agent for iron and an oxidizer in a fourth step. A solution of chelated iron from the fourth step is disposed of.

Abstract: Geothermal brine and other platinum-containing solutions are passed through a carbon-containing zone to recover platinum from the aqueous medium.

Abstract: Radioactivity and fluoride ion are inhibited or prevented from precipitating in scale formed from a geothermal brine by adding a scale inhibitor to the cooling brine solution. Preferred scale inhibitors include polyacrylate dispersants and phosphonomethylated amines.