Abstract: A method of treating, stabilizing, precipitating, or otherwise removing heavy metal ions contained in a contaminated media, which method includes: providing a sodium-iron-sulfide mineral or crystalline phase, either alone or in combination with a pH adjusting substance; contacting said contaminated media containing heavy metal ions with the sodium-iron-sulfide mineral or crystalline phase, either alone or in combination with a pH adjusting substance; and allowing the contaminated media containing the heavy metal ions to react with said sodium-iron-sulfide mineral or crystalline phase, either alone or in combination with a pH adjusting substance, such that the contaminated media containing heavy metal ions form single or mixed metal-sulfide precipitates or co-precipitates.

Abstract: A method of treating, stabilizing, precipitating, or otherwise removing heavy metal ions contained in a contaminated media, which method includes: providing a sodium-iron-sulfide mineral or crystalline phase, either alone or in combination with a pH adjusting substance; contacting said contaminated media containing heavy metal ions with the sodium-iron-sulfide mineral or crystalline phase, either alone or in combination with a pH adjusting substance; and allowing the contaminated media containing the heavy metal ions to react with said sodium-iron-sulfide mineral or crystalline phase, either alone or in combination with a pH adjusting substance, such that the contaminated media containing heavy metal ions form single or mixed metal-sulfide precipitates or co-precipitates.

Abstract: Methods for treatment a heavy metal-contaminated solid, semi-solid, liquid or gaseous matrix with magnesium oxide, magnesium sulfite, magnesium sulfate, magnesium chloride, magnesium hydroxide, and mixtures of any two or more of these. Methods for treatment of a solid or semi-solid waste containing unacceptable levels of leachable aluminum and reactive metallic aluminum-containing waste with magnesium oxide, magnesium sulfite, magnesium sulfate, magnesium hydroxide, magnesium chloride, and mixtures of any two or more of these.

Abstract: A wet gas scrubber liquor and method of using the same to remove mercury from flue gases. The wet gas scrubber liquid is an alkaline liquid suspension of ferrous sulfide particles that can be prepared by combining together a ferrous ion source such as ferrous chloride, a sulfide ion source such as sodium hydrosulfide and an alkalinity source such as sodium hydroxide. When used to scrub flue gases to remove mercury from flue gases the mercury reacts with said alkaline liquid suspension of ferrous sulfide particles and can be removed by at least one of: i) adsorption onto said ferrous sulfide particles; ii) adsorption onto iron (hydr)-oxides that form in said alkaline liquid suspension of ferrous sulfide particles; and iii) absorption by reacting with sulfur formed in alkaline liquid suspension of ferrous sulfide particles and forming mercuric sulfide as a precipitate.

Abstract: A ferrous sulfide suspension that includes at least FeSm and Al(OH)3 and which can be used to reduce mercury emissions in flue gases. Through a combination of complex chemical reactions, precipitation, co-precipitation, and surface adsorption the ferrous sulfide suspension of the present invention effectively removes mercury from gaseous streams while concurrently preventing mercury re-emission.

Abstract: A wet gas scrubber liquor and method of using the same to remove mercury from flue gases. The wet gas scrubber liquid is an alkaline liquid suspension of ferrous sulfide particles that can be prepared by combining together a ferrous ion source such as ferrous chloride, a sulfide ion source such as sodium hydrosulfide and an alkalinity source such as sodium hydroxide. When used to scrub flue gases to remove mercury from flue gases the mercury reacts with said alkaline liquid suspension of ferrous sulfide particles and can be removed by at least one of: i) adsorption onto said ferrous sulfide particles; ii) adsorption onto iron (hydr)-oxides that form in said alkaline liquid suspension of ferrous sulfide particles; and iii) absorption by reacting with sulfur formed in alkaline liquid suspension of ferrous sulfide particles and forming mercuric sulfide as a precipitate.

Abstract: Methods to reduce hexavalent chromium (Cr(VI)) in chromite processing wastes include one or more of the following steps: contacting the chromite processing wastes with an oxygen scavenger or chemical reducer; permitting the chromite processing wastes to react with the oxygen scavenger or chemical reducer; contacting the chromite processing wastes with ferrous ion; contacting the chromite processing wastes with sulfide ion; and, contacting the chromite processing wastes with ferrous sulfide.

Abstract: Methods to reduce hexavalent chromium (Cr(VI)) in chromite processing wastes include one or more of the following steps: contacting the chromite processing wastes with an oxygen scavenger or chemical reducer; permitting the chromite processing wastes to react with the oxygen scavenger or chemical reducer; contacting the chromite processing wastes with ferrous ion; contacting the chromite processing wastes with sulfide ion; and, contacting the chromite processing wastes with ferrous sulfide.

Abstract: Methods to reduce hexavalent chromium (Cr(VI)) in chromite processing wastes include one or more of the following steps: contacting the chromite processing wastes with an oxygen scavenger or chemical reducer; permitting the chromite processing wastes to react with the oxygen scavenger or chemical reducer, contacting the chromite processing wastes with ferrous ion; contacting the chromite processing wastes with sulfide ion; and, contacting the chromite processing wastes with ferrous sulfide.

Abstract: Methods to reduce hexavalent chromium (Cr(VI)) in chromite processing wastes include one or more of the following steps: contacting the chromite processing wastes with an oxygen scavenger or chemical reducer; permitting the chromite processing wastes to react with the oxygen scavenger or chemical reducer; contacting the chromite processing wastes with ferrous ion; contacting the chromite processing wastes with sulfide ion; and, contacting the chromite processing wastes with ferrous sulfide.

Abstract: Methods for treatment a heavy metal-contaminated solid, semi-solid, liquid or gaseous matrix with magnesium oxide, magnesium sulfite, magnesium sulfate, magnesium chloride, magnesium hydroxide, and mixtures of any two or more of these. Methods for treatment of a solid or semi-solid waste containing unacceptable levels of leachable aluminum and reactive metallic aluminum-containing waste with magnesium oxide, magnesium sulfite, magnesium sulfate, magnesium hydroxide, magnesium chloride, and mixtures of any two or more of these.