A method for vitrification of arsenic and antimony, comprising substituting oxygen to sulfur on thiosalts, incorporating resulting sodium arsenate and sodium antimonate into a sodium silicate glass-forming mixture and vitrifying the sodium silicate glass-forming mixture into a resulting glass sequestering the arsenic and antimony.

An oxidation step for sulfide and transition ores prior to CN leaching to recover 60 to 90 percent of metals from those ores. Use of tona, soda ash or carbonate source in treating sulfide and transition ores for CN leaching recovery of metals, including gold and silver. The oxidation of sulfide and transition ores in the presence of carbonate. Low moisture content in the heap, to enhance available oxygen, during the oxidation of sulfide and transition ores in the presence of carbonate.

An oxidation step for sulfide and transition ores prior to CN leaching to recover 60 to 90 percent of metals from those ores. Use of tona, soda ash or carbonate source in treating sulfide and transition ores for CN leaching recovery of metals, including gold and silver. The oxidation of sulfide and transition ores in the presence of carbonate. Low moisture content in the heap, to enhance available oxygen, during the oxidation of sulfide and transition ores in the presence of carbonate.

Methods of extracting rare earth elements (REEs) from low-grade REE sources composed of clayey materials. In one aspect, the REE sources are the waste materials generated in the coal and kaolin clay industries during the courses of upgrading mined coal and kaolinite. The methods described herein include the steps of pre-concentrating REE-bearing minerals using physical separation methods to prepare high-grade feedstocks for the chemical extraction of high-value REEs and critical materials while minimizing both the capital and operating costs.

Methods of extracting rare earth elements (REEs) from low-grade REE sources composed of clayey materials. In one aspect, the REE sources are the waste materials generated in the coal and kaolin clay industries during the courses of upgrading mined coal and kaolinite. The methods described herein include the steps of pre-concentrating REE-bearing minerals using physical separation methods to prepare high-grade feedstocks for the chemical extraction of high-value REEs and critical materials while minimizing both the capital and operating costs.

The invention relates to a method for producing a ferroalloy containing nickel. From a fine-grained raw material containing iron and chromium and a fine-grained raw material containing nickel, a mixture is formed with binding agent, the mixture is agglomerated so that first formed objects of desired size are obtained. The objects formed are heat treated in order to strengthen the objects so that the heat treated objects withstand conveyance and loading into a smelter furnace. Further, the objects are smelted under reducing circumstances in order to achieve ferrochromenickel, a ferroalloy of a desired composition containing at least iron, chromium and nickel.

The invention relates to a method for producing a ferroalloy containing nickel. From a fine-grained raw material containing iron and chromium and a fine-grained raw material containing nickel, a mixture is formed with binding agent, the mixture is agglomerated so that first formed objects of desired size are obtained. The objects formed are heat treated in order to strengthen the objects so that the heat treated objects withstand conveyance and loading into a smelter furnace. Further, the objects are smelted under reducing circumstances in order to achieve ferrochromenickel, a ferroalloy of a desired composition containing at least iron, chromium and nickel.

Present invention describes a biotechnological procedure to remove magnetic sulfur impurities from iron concentrate, CHARACTERIZED because it includes: to bioleach iron concentrate ores agglomerated in heaps under temperature condition between 5 and 35 C., inoculating the iron concentrate ores with Acidithiobacillus thiooxidans cultures, with an inoculum concentration 10.sup.4 and 10.sup.6 cel/g and addition of water supplemented with nitrogen and phosphorous source (0.01 to 0.5 g (NH.sub.4).sub.2HPO.sub.4/L), without potassium addition, adjusting pH between 1.0 and 9.0, and a feeding rate between 5 and 15 L/h/m.sup.2; this procedure allows a removal efficiency above 80% in 21 days, with a maximum iron loss of 3%.

Present invention describes a biotechnological procedure to remove magnetic sulfur impurities from iron concentrate, CHARACTERIZED because it includes: to bioleach iron concentrate ores agglomerated in heaps under temperature condition between 5 and 35 C., inoculating the iron concentrate ores with Acidithiobacillus thiooxidans cultures, with an inoculum concentration 10.sup.4 and 10.sup.6 cel/g and addition of water supplemented with nitrogen and phosphorous source (0.01 to 0.5 g (NH.sub.4).sub.2HPO.sub.4/L), without potassium addition, adjusting pH between 1.0 and 9.0, and a feeding rate between 5 and 15 L/h/m.sup.2; this procedure allows a removal efficiency above 80% in 21 days, with a maximum iron loss of 3%.

Various embodiments utilize selective sulfidation and/or desulfidation for such things as ore and concentrate cracking, metal separation, compound production, and recycling. Selective sulfidation can be used to selectively convert an oxide or other material in a feedstock to a sulfide or other sulfur-containing material, and selective desulfidation can be used to selectively convert a sulfide or other sulfur-containing material in a feedstock to an oxide or other material. In some cases, the material produced by such selective sulfidation/desulfidation of the feedstock can itself be novel and/or commercially valuable, while in other cases, such selective sulfidation/desulfidation can be followed by one or more processes to extract, isolate, or concentrate the converted material.