An improved method for recovering metals from spent catalysts, particularly from spent slurry catalysts, is disclosed. The method and associated processes comprising the method are useful to recover catalyst metals used in the petroleum and chemical processing industries. The method generally involves a pyrometallurgical method and a hydrometallurgical method and includes forming a soda ash calcine of a caustic leach residue of the spent catalyst containing an insoluble Group VIII/Group VIB/Group VB metal compound combined with soda ash, and extracting and recovering soluble Group VIB metal and soluble Group VB metal compounds from the soda ash calcine.

The disclosure relates to pre-treatment of precious metal-bearing oxide ores, prior to precious metal leaching by thiosulfate. The process comprises mixing oxide ore in oxygenated water in the presence of a carbon-based material (e.g., activated carbon or other type of carbon). The carbon-based material can be separated from the ore slurry, and, the gold is thereafter leached by a thiosulfate lixiviant.

The disclosure relates to pre-treatment of precious metal-bearing oxide ores, prior to precious metal leaching by thiosulfate. The process comprises mixing oxide ore in oxygenated water in the presence of a carbon-based material (e.g., activated carbon or other type of carbon). The carbon-based material can be separated from the ore slurry, and, the gold is thereafter leached by a thiosulfate lixiviant.

The present invention discloses a method for decomposing medium-/low-grade scheelite, specifically comprising steps of: grinding medium-/low-grade scheelite, decomposing in an autoclave by using sodium phosphate and activated magnesium fluoride as leaching agents, and treating by solid-liquid separation to obtain crude sodium tungstate solution and residue. In this way, the medium-/low-grade scheelite is decomposed. Magnesium chloride is added in a sodium fluoride solution to prepare activated magnesium fluoride as a leaching agent. The present invention has the advantage that the high-efficiency decomposition of medium-/low-grade scheelite can be realized with low consumption of leaching agents, and the leaching cost can be greatly reduced in comparison to the existing decomposition processes using sodium hydroxide and sodium carbonate. This process is short in route, simple in operation, readily available and reliable in production equipment, and easy for industrialization.

The present invention discloses a method for decomposing medium-/low-grade scheelite, specifically comprising steps of: grinding medium-/low-grade scheelite, decomposing in an autoclave by using sodium phosphate and activated magnesium fluoride as leaching agents, and treating by solid-liquid separation to obtain crude sodium tungstate solution and residue. In this way, the medium-/low-grade scheelite is decomposed. Magnesium chloride is added in a sodium fluoride solution to prepare activated magnesium fluoride as a leaching agent. The present invention has the advantage that the high-efficiency decomposition of medium-/low-grade scheelite can be realized with low consumption of leaching agents, and the leaching cost can be greatly reduced in comparison to the existing decomposition processes using sodium hydroxide and sodium carbonate. This process is short in route, simple in operation, readily available and reliable in production equipment, and easy for industrialization.

A process to recover nickel, cobalt and copper by co-processing copper-containing sulphide concentrate feed containing one or more of arsenic, antimony, and bismuth, and laterite ore feed containing nickel and cobalt by pressure oxidative leaching. The sulphide concentrate and oxygen are controlled to produce sulphuric acid to leach nickel, cobalt, copper and acid soluble impurities into a liquid phase of an acidic leach slurry, to precipitate iron compounds and a majority of the arsenic, antimony and bismuth as solids, and to produce heat to heat the incoming feeds to a temperature above 230° C. Reacted slurry is withdrawn, solids are separated, and the PLS solution contains the nickel, cobalt, copper and acid soluble impurities. A first solution purification stage on the PLS neutralizes free acid, precipitates one or more of iron, aluminum, chromium and silicon, and, separates as solids, the precipitated impurities and other solids from a first purified solution. Copper is separated from the first purified solution with a solvent extraction step to produce a raffinate solution reduced in copper and a copper loaded organic phase. The organic phase is stripped and copper is recovered with electrowinning. A second solution purification stage is conducted on the raffinate by one or both of neutralizing free acid and precipitating one or more of iron, aluminum, chromium and silicon, followed by separating as solids, the precipitated impurities and other solids from a second purified solution. Nickel and cobalt are recovered as mixed hydroxides or mixed sulphides from the second purified solution.

An adsorption process for acquiring lithium from brine, in which the desorption occurs with an eluent, whereby the eluent is a mixture of water and acetic acid and/or water and sodium peroxydisulfate and/or water and ammonium peroxydisulfate.

A method for cleanly extracting metallic silver includes: mixing an acidic solution containing Ce.sup.4+ and NO.sub.3.sup.− with a silver-containing material for leaching; after the leaching is completed, carrying out a solid-liquid separation to obtain a leaching solution containing Ce.sup.3+ and Ag.sup.+; and electrolyzing the leaching solution, wherein an oxidation reaction of Ce′ occurs at an anode to realize a regeneration of Ce.sup.4+ and an electrolytic reduction occurs at a cathode to reduce Ag.sup.+ to obtain the metallic silver. Ce.sup.4+ is used as a leaching agent and an intermediate oxidant to implement a cyclic operation of solution leaching and electrolytic regeneration on the silver-containing material. Almost no NO.sub.x and waste liquid are caused by the extraction process, and the invention is clean and environmentally friendly.

This disclosure describes systems, methods, and apparatus for counter-current solids leaching. A multi-stage countercurrent leaching chamber can include a top and bottom end, a barren liquor input, two or more regions for countercurrent mixing, and a barren solids output. The input can be configured to receive barren liquor. The two or more regions for countercurrent mixing and separation can be configured to mix and separate liquid and solid phases. The barren solids output can be configured to collect and discharge barren solids from the bottom end of the multi-stage countercurrent leaching chamber. A fluidized bed chamber and clarifier chamber can also be included, where the fluidized bed receives a fluidizable slurry of pregnant solids and the clarifier chamber aids in separating liquids from solids passing from a top of the fluidized bed chamber to the top end of the multi-stage countercurrent leaching chamber.

This disclosure describes systems, methods, and apparatus for counter-current solids leaching. A multi-stage countercurrent leaching chamber can include a top and bottom end, a barren liquor input, two or more regions for countercurrent mixing, and a barren solids output. The input can be configured to receive barren liquor. The two or more regions for countercurrent mixing and separation can be configured to mix and separate liquid and solid phases. The barren solids output can be configured to collect and discharge barren solids from the bottom end of the multi-stage countercurrent leaching chamber. A fluidized bed chamber and clarifier chamber can also be included, where the fluidized bed receives a fluidizable slurry of pregnant solids and the clarifier chamber aids in separating liquids from solids passing from a top of the fluidized bed chamber to the top end of the multi-stage countercurrent leaching chamber.