Institut National De La Recherche Scientifique

Institut National De La Recherche

Centre De Recherche Industrielle Du Quebec

Tremblay, Richard

Jean-Francois Blais

Guy Mercier

Sandra Elizabeth Kentish

Emmanuelle Cecchi

Louis-Cesar Pasquier

Sanoopkumar Puthiya Veetil

Rajeshwar D Tyagi

Sandra Kentish

Gerardo Buelna

Myriam Chartier

Patrick Drogui

Julia Mouton

Brahima Seyhi

Nathalie Meunier

Jean-Louis Sasseville

Fatima Hammy

Jean C Auclair

Amelie Janin

Marc-Andre Bureau

Techniques are described for chemical sequestration of carbon dioxide and production of precipitated magnesium carbonate. The process can include contacting carbon dioxide from industrial emissions with water and magnesium-containing particulate material, such as serpentinite, which is thermally pre-treated and has a particle size of at most 75 microns. The process can also include separation of the loaded aqueous stream from the solids, followed by precipitation of magnesium carbonate material that includes carbon and oxygen from industrial emissions and magnesium from serpentinite or chrysotile mining residue, for example.

Carbon dioxide chemical sequestration from industrial emissions by carbonation

Processes, methods, system and uses in relation to chemical sequestration of carbon dioxide from a carbon dioxide containing gas by carbonation of an alkaline earth metal containing material. The carbon dioxide containing gas is contacted with an aqueous slurry in a carbonation unit for carbonation of at least a portion of the alkaline earth metal to produce a carbon dioxide depleted gas and a carbonate loaded slurry which is substantially exempt of precipitated alkaline earth. metal carbonates. The carbonate loaded slurry is then separated into an aqueous phase and a solid phase; and the aqueous phase is supplied to a precipitation unit for precipitating alkaline earth metal carbonates. The carbonation stage may be performed at a carbonation temperature between about 10&#xb0; C. and about 40&#xb0; C. and a carbonation pressure between about 1 bar and about 20 bars. The solid phase may be recycled to the carbonation stage.

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.

Process, decontaminant and chemical kit for the decontaminating media polluted with metals and hydrophobic organic compounds

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.

Hybrid chemical and biological process for decontaminating sludge from municipal sewage

The present invention relates to a semi-continuous process for removing heavy metals, substantially reducing volatile suspended solids and substantially destroying indicator bacteria from municipal sludges, which comprises: a) adding 1 to 3 g of sulphur per liter to a volume of municipal sludge and allowing the sulphur oxidizing thiobacilli initially present in said sludge to proliferate under aerobic conditions in said sludge being agitated until the pH of said sludge is lowered to about 1.5 to 2.5 which causes heavy metals present in said sludge to be substantially solubilized, the concentration of volatile suspended solids is substantially reduced and the concentration of indicator bacteria to be lowered to a non-toxic level; b) removing about 90% of said low pH sludge and recovering the solubilized heavy metals therefrom; c) adding about 90% of municipal sludge to the remaining low pH sludge of step b), thereby resulting in a sludge mixture having a pH of about 7 to 8; and d) repeating steps a) to c); whereby the thiobacilli are adapted when the time required for lowering the pH of the sludge to 1.5 to 2.5 is about the same in two successive operations.

Semi-continuous bacterial leaching process

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Jean-Francois Blais