摘要:
The present invention relates to the phytoextraction of heavy metals from the soil, and more particularly nickel in the form of a crystallized salt. The present invention includes, in particular, a process of producing a crystallized nickel salt from the ashes of a hyperaccumulator plant that accumulates metal elements nickel-containing, a use of the hyperaccumulator plant for the production of the crystallized nickel salt, and a purified composition of the crystallized nickel salt which is derived from the ashes of the hyperaccumulator plant.
摘要:
Hydrometallurgical techniques for the selective recovery of Zn, Mn and Pb in that order from sludges or various metallurgical residues can include leaching steps to extract the zinc and manganese; the steps of removing iron, aluminum and silica from the leaching solutions; and recovering manganese and zinc by precipitation. Mn can be precipitated from an initial leaching solution as well as a secondary leaching solution obtained by leaching the slurry of the initial leaching step. Various other waste streams can also be treated.
摘要:
A process for decontaminating a medium polluted with metals and hydrophobic organic compounds (HOC) includes providing an acidic slurry of water, acid, chloride salt, surfactant, and the polluted medium. Flotation is preformed on the acidic slurry to form a HOC-rich froth and an HOC-depleted slurry and the froth is recovered. The slurry is separated to obtain a treated solid and a liquid effluent rich in metallic ions. Preferably, the process also includes recuperating the metals by chemical precipitation and/or electrodeposition to produce a treated solution. Also provided are a decontaminant having an acid, a chloride salt, and a surfactant as well as a chemical kit for decontaminating the polluted medium including the decontaminant in which the acid, chloride salt and surfactant can be mixed with polluted medium in the presence of water before removing at least a portion of the metals and HOC from the polluted medium.
摘要:
A process for producing magnesia can include contacting CO 2 -containing emissions with a magnesium-containing material to produce magnesium carbonate; subjecting the magnesium carbonate to calcination to produce a CO 2 by-product and magnesia; and recycling at least a portion of the CO 2 by-product for contacting the magnesium-containing material to produce the magnesium carbonate. The magnesium-containing material can include mining residues, such as phyllosilicate or chrysotile mining residue, and the magnesium carbonate produced can include precipitated nesquehonite that is subjected to calcination to produce the magnesia.
摘要:
The invention relates to a hybrid biological and chemical method for decontaminating sludge containing heavy metals and pathogenic microorganisms, consisting of the following steps: the sludge is mixed with an acidic leaching solution in order to acidify the sludge with a pH which is low enough to solubilize the majority of the heavy metals and to destroy most of the pathogenic microorganisms but which is also high enough to minimize the solubilization of fertilizing elements; oxidation-reduction of more than +400 mv is maintained, liquid-solid separation occurs in order to obtain a solid fraction comprising decontaminated acidic sludge and a liquid fraction comprising heavy metals which are dissolved in a leaching solution; the sludge is neutralized: and neturalized decontaminated sludge is recovered, whereby the fertilizing elements contained therein, i.e. carbon, nitrogen and phosphorus, remain substantially unchanged in relation to the initially contaminated sludge.
摘要:
A process for producing magnesia can include contacting CO 2 -containing emissions with a magnesium-containing material to produce magnesium carbonate; subjecting the magnesium carbonate to calcination to produce a CO 2 by-product and magnesia; and recycling at least a portion of the CO 2 by-product for contacting the magnesium-containing material to produce the magnesium carbonate. The magnesium-containing material can include mining residues, such as phyllosilicate or chrysotile mining residue, and the magnesium carbonate produced can include precipitated nesquehonite that is subjected to calcination to produce the magnesia.