Arsenic-containing waste stabilisation and solidification

• Main Authors: GARNIER ANDRE, LOIGNON ROBERT ADOLPHE, LAGOUTTE ANNIE
• Format: Patent
• Language: English; French
• Published: 14.08.1998
• Edition: 6
• Subjects: ARTIFICIAL STONE; CEMENTS; CERAMICS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS; CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING ORPROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMISTRY; CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATERTREATMENT OR WASTE MANAGEMENT; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDINGMATERIALS; CONCRETE; FIRE-FIGHTING; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; HUMAN NECESSITIES; LIFE-SAVING; LIME, MAGNESIA; METALLURGY; REFRACTORIES; SLAG; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINSTCLIMATE CHANGE; TREATMENT OF NATURAL STONE; TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE

A process is claimed for treating special industrial wastes, mining wastes, excavated earth, soils, slags, sludges and liquids contaminated with (per kg dry material) \} 57000 mg arsenic in the form of arsenic derivatives of various oxidation states, together with \} 23000 mg polluting and toxic substances such as Bi, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Sb, Sn and Zn. The process involves (a) stabilising the arsenic constituents in the presence of a trivalent metal by oxidation to the pentavalent state to reduce their solubility and increase their retention within a confinement matrix; and (b) reacting the products of step (a) with a confinement phase consisting of a very high performance cement and fine aggregate to form a solid which satisfies the No. 1 technical landfill centre (CET 1) admission criteria: pH 4-13 exclusive, dryness 35%, soluble fraction less than 10% and less than 10 mg As/kg according to the standard X 31-210. Also claimed is an industrial unit for carrying out the above process, the unit having a discontinuous or continuous stabilisation system, with a three phase (gas/liquid/solid) reactor, and a discontinuous blender-mixer for the solidification step. L'invention concerne un procédé nouveau, ainsi que le dispositif de sa mise en oeuvreindustrielle pour le traitement des substances solides et liquides contaminées par l'arsenic etles dérivés arsenicaux. Un tel procédé présente deux phases distinctes : - La première phase consiste en la transformation, la complexation et la préstabilisation des agents polluants de degrés d'oxydation variés, par l'action des agents d'oxydation. - La seconde phase qui exige une concentration subséquente consiste en l'absorption, la cristallisation, la solidification, et la stabilisation, des substances traitées, par combinaison en milieu homogène avec une matrice abrasée de granulométrie et surface d'adsorption spécifiques. Le solidifiat ainsi obtenu satisfait aux procédures d'évaluation des procédés de stabilisation/ solidification et aux critères d'admission propres aux déchets stabilisés, dans les centres d'enfouissement technique 1.