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.

A process for producing DRI from iron ores, utilizing a gas produced from fossil fuels, containing sulfur compounds and BTX, heating said gas in a heater, preferably a regenerator, wherein heat is transferred from a previously-heated solid material to the gas. Flowing the hot gas through a bed of DRI particles, iron oxides or other equivalent material, outside of the reduction reactor, where said material adsorbs sulfur compounds and destroys BTX. The resulting gas, free from sulfur compounds and BTX, is combined with a reducing gas stream from the reduction reactor after H.sub.2O and CO.sub.2 is at least partially removed for regenerating its reducing potential, with or without undergoing previous cleaning, is used for producing DRI. One inventive embodiment comprises producing DRI at high temperature giving advantageously higher productivity and energy savings when using hot DRI in an electric arc furnace lowering the capital and operational costs of steelmaking.

A process for producing DRI from iron ores, utilizing a gas produced from fossil fuels, containing sulfur compounds and BTX, heating said gas in a heater, preferably a regenerator, wherein heat is transferred from a previously-heated solid material to the gas. Flowing the hot gas through a bed of DRI particles, iron oxides or other equivalent material, outside of the reduction reactor, where said material adsorbs sulfur compounds and destroys BTX. The resulting gas, free from sulfur compounds and BTX, is combined with a reducing gas stream from the reduction reactor after H.sub.2O and CO.sub.2 is at least partially removed for regenerating its reducing potential, with or without undergoing previous cleaning, is used for producing DRI. One inventive embodiment comprises producing DRI at high temperature giving advantageously higher productivity and energy savings when using hot DRI in an electric arc furnace lowering the capital and operational costs of steelmaking.

A method removes phosphorus from a phosphorus-containing substance. In the method, the phosphorus-containing substance that is used as a raw material for metal smelting or refining is reacted with a nitrogen-containing gas so that phosphorus in the phosphorus-containing substance is removed through nitriding. Prior to a treatment of a nitriding removal of phosphorus from the phosphorus-containing substance, a treatment is performed in which the phosphorus-containing substance is heated to an unmolten state temperature range so as to react with a reducing agent, thereby reducing at least a part of metal oxide in the phosphorus-containing substance.

A method removes phosphorus from a phosphorus-containing substance. In the method, the phosphorus-containing substance that is used as a raw material for metal smelting or refining is reacted with a nitrogen-containing gas so that phosphorus in the phosphorus-containing substance is removed through nitriding. Prior to a treatment of a nitriding removal of phosphorus from the phosphorus-containing substance, a treatment is performed in which the phosphorus-containing substance is heated to an unmolten state temperature range so as to react with a reducing agent, thereby reducing at least a part of metal oxide in the phosphorus-containing substance.

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.