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AssigneePolution Sciences Laboratory Incorporated
InventorsTaiichiro Sasae, Tomio Nishida, Kazuya Katayama, Masanori Oshima
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The present invention provides an immobilizing agent for making harmless the detrimental metals contained in fly ash formed from an urban dust incinerating plant and a method for immobilizing the fly ash. The treating agent according to the present invention contains .alpha. starch and/or dextrin (component A), sodium silicate and/or a hydrogen phosphate compound (component B) and an allophane having a molecular ratio of SiO.sub.2 /Al.sub.2 O.sub.3 of not lower than 2 (component C). It may also further contain cement, bentonite, calcined gypsum and fly ash formed from a coal thermoelectric power plant. The mixing ratio of the components A, B and C is preferably 100 parts by weight: 20 to 160 parts by weight: 40 to 180 parts by weight respectively. The treating agent is mixed with the above-mentioned fly ash and water is added to it and the mixture is milled and then used. The treating agent of the present invention can enclose detrimental metals stably with no second elution and thus is effective for immobilizing treatment.
A treating agent for immobilizing fly ash of an urban dust incinerator, the fly ash contains at least one noxious metal selected from the group consisting of cadmium, lead, zinc and copper, the treating agent comprises a mixture of components A, B and C, where component A is selected from the group consisting of .alpha. starch and dextrin, component B is selected from the group consisting of sodium silicate and a hydrogen phosphate compound, and component C is an allophane having a molecular ratio of SiO.sub.2 /Al.sub.2 O.sub.3 of not less than 2, wherein the mixing ratio of said component A:
A method for the treatment for immobilizing fly ash of an urban dust incinerator, wherein the fly ash contains at least one noxious metal selected from the group consisting of cadmium, lead, zinc and copper, and, the treating agent comprises a mixture of components A, B and C, where component A is selected from the group consisting of .alpha. starch and dextrin, component B is selected from the group consisting of sodium silicate and a hydrogen phosphate compound, and component C is an allophane having a molecular ratio of SiO.sub.2 /Al.sub.2 O.sub.3 of not less than 2, wherein the mixing ratio of said component A:
Dependencies are inferred from the claim text.