Insolubilizing agent for specific toxic substances, method for insolubilizing specific toxic substances using same, and soil improving method

Abstract

Provided is a practically valuable and economically excellent insolubilizing material for a specific toxic substance: that is useful for insolubilizing treatment for a heavy metal or the like conducted by applying the insolubilizing material for a specific toxic substance to soil or on the surface of the soil; that is capable of effectively insolubilizing and immobilizing the heavy metal or the like; that is capable of making treated matter neutral so as to be reusable and environment-friendly; and moreover that is capable of imparting strength to the treated matter as necessary; and with which the heavy metal or the like is not re-eluted even when the treated matter is exposed to an environment under a neutral condition or an acidic condition. An insolubilizing material for a specific toxic substance to be used so that soil does not reach a strongly alkaline region of a pH of 11 or more, wherein the insolubilizing material for a specific toxic substance comprises an amorphous aluminum compound or a derivative thereof as a main component, or an insolubilizing material for a specific toxic substance to be used so that soil containing a heavy metal or the like does not reach a strongly alkaline region of a pH of 11 or more, the insolubilizing material for a specific toxic substance functioning also as a solidifying material, wherein the insolubilizing material for a specific toxic substance comprises gypsum obtained by adding and mixing, to the gypsum, the amorphous aluminum compound and the derivative thereof in a range of 0.5 to 60 mass parts relative to 100 mass parts of the gypsum, and a method for improving soil using the insolubilizing material for a specific toxic substance.

1 . An insolubilizing material for a specific toxic substance to be used so that soil does not reach a strongly alkaline region of a pH of 11 or more, the insolubilizing material for a specific toxic substance comprising an amorphous aluminum compound or a derivative thereof as a main component,
 wherein the amorphous aluminum compound or the derivative thereof is amorphous aluminum hydroxide or a derivative thereof.   
     
     
         2 . An insolubilizing material for a specific toxic substance to be used so that soil does not reach a strongly alkaline region of a pH of 11 or more, the insolubilizing material for a specific toxic substance comprising an amorphous aluminum compound or a derivative thereof as a main component,
 wherein the insolubilizing material for a specific toxic substance further comprises a calcium component exhibiting acidity, neutrality, or weak alkalinity of a pH of less than 11 when the calcium component makes contact with moisture contained in the soil.   
     
     
         3 . An insolubilizing material for a specific toxic substance to be used so that soil containing a specific toxic substance does not reach a strongly alkaline region of a pH of 11 or more, the insolubilizing material for a specific toxic substance comprising an amorphous aluminum compound or a derivative thereof as a main component,
 wherein the insolubilizing material for a specific toxic substance further comprises calcined gypsum, and   the insolubilizing material for a specific toxic substance comprising the calcined gypsum is obtained by adding and mixing, to the calcined gypsum, the amorphous aluminum compound or the derivative thereof in a range of 0.5 to 60 mass parts relative to 100 mass parts of the calcined gypsum.   
     
     
         4 . The insolubilizing material for a specific toxic substance according to  claim 2 , wherein the amorphous aluminum compound is amorphous aluminum hydroxide. 
     
     
         5 . The insolubilizing material for a specific toxic substance according to  claim 1 , wherein the amorphous aluminum compound or the derivative thereof, or the amorphous aluminum hydroxide or the derivative thereof is derived from aluminum sludge and is to be used as it is; or obtained by dehydrating and drying, without changing the properties, an amorphous aluminum compound or a derivative thereof, or amorphous aluminum hydroxide or a derivative thereof derived from aluminum sludge. 
     
     
         6 . The insolubilizing material for a specific toxic substance according to  claim 1 , wherein the specific toxic substance is at least any one selected from the group consisting of cadmium and compounds thereof, hexavalent chromium compounds, cyanides, mercury and compounds thereof (including alkyl mercury compounds), selenium and compounds thereof, lead and compounds thereof, arsenic and compounds thereof, fluorine and compounds thereof, and boron and compounds thereof. 
     
     
         7 . The insolubilizing material for a specific toxic substance according to  claim 2 , wherein the calcium component is at least any one selected from the group consisting of gypsum dihydrate, calcium carbonate, calcium peroxide, calcium fluoride, calcium iodide, calcium phosphate, calcium chloride, calcium nitrate, calcium acetate, calcium citrate, calcium gluconate, calcium malate, and calcium lactate. 
     
     
         8 . The insolubilizing material for a specific toxic substance according to  claim 3 , wherein the insolubilizing material for a specific toxic substance is obtained by adding and mixing, to the calcined gypsum, the amorphous aluminum compound and the derivative thereof in a range of 15 to 50 mass parts relative to 100 mass parts of the calcined gypsum. 
     
     
         9 . A method for insolubilizing a specific toxic substance, the method comprising conducting treatment to soil so that the soil does not reach a strongly alkaline region of a pH of 11 or more by adding and mixing, or spraying to the soil the insolubilizing material for a specific toxic substance according to  claim 1  to insolubilize the specific toxic substance. 
     
     
         10 . The method for insolubilizing a specific toxic substance according to  claim 9 , the method comprising adding and mixing, or spraying to the soil the amorphous aluminum compound or the derivative thereof, or the amorphous aluminum hydroxide or the derivative thereof being a main component of the insolubilizing material for a specific toxic substance within a range of 0.5 to 50 g per 1 kg on a dry mass basis of the soil. 
     
     
         11 . The method for insolubilizing a specific toxic substance according to  claim 9 , the method comprising adding and mixing, or spraying to the soil the amorphous aluminum compound and the derivative thereof, or the amorphous aluminum hydroxide or the derivative thereof being a main component of the insolubilizing material for a specific toxic substance within a range of 10 to 40 g per 1 kg on a dry mass basis of the soil. 
     
     
         12 . The method for insolubilizing a specific toxic substance according to  claim 9 , wherein the specific toxic substance to be insolubilized is attributable to the soil or a constituent of the insolubilizing material. 
     
     
         13 . The method for insolubilizing a specific toxic substance according to  claim 12 , wherein the constituent of the insolubilizing material is a calcium component. 
     
     
         14 . A method for improving soil, comprising conducting treatment to the soil containing a specific toxic substance so that the soil does not reach a strongly alkaline region of a pH of 11 or more by adding and mixing to the soil the insolubilizing material for a specific toxic substance functioning also as a solidifying material according to  claim 3 . 
     
     
         15 . The method for improving soil according to  claim 14 , comprising adding and mixing to the soil the insolubilizing material for a specific toxic substance within a range of 30 to 200 kg per 1 m 3  of the soil containing a specific toxic substance.