A method of valuation of raw fines materials, comprising selectively screening, biotreatment or composting of raw fines materials or selection as fillers in composites. The method comprises screening the raw fines materials to Grade 1 comprising fines materials of a size of at most about 5 mm and Grade 2 comprising fines materials of a size larger than about 5 mm; and at least one of: A) bio-oxydating organic contaminants of the Grade 1; by adding and mixing organic amendment under controlled temperature, nutrients content and water content conditions and monitoring a content of organic contaminants until the content of organic contaminants stops decreasing; and B) composting the Grade 1; by adding and mixing organic amendment under controlled temperature, nutrients content and water content conditions, and monitoring pathogens content and respiration rate; and stopping the addition of organic amendment upon detection of absence of pathogens at a predetermined respiration rate.

A method of valuation of raw fines materials, comprising selectively screening, biotreatment or composting of raw fines materials or selection as fillers in composites. The method comprises screening the raw fines materials to Grade 1 comprising fines materials of a size of at most about 5 mm and Grade 2 comprising fines materials of a size larger than about 5 mm; and at least one of: A) bio-oxydating organic contaminants of the Grade 1; by adding and mixing organic amendment under controlled temperature, nutrients content and water content conditions and monitoring a content of organic contaminants until the content of organic contaminants stops decreasing; and B) composting the Grade 1; by adding and mixing organic amendment under controlled temperature, nutrients content and water content conditions, and monitoring pathogens content and respiration rate; and stopping the addition of organic amendment upon detection of absence of pathogens at a predetermined respiration rate.

A method of valuation of raw fines materials, comprising selectively screening, biotreatment or composting of raw fines materials or selection as fillers in composites. The method comprises screening the raw fines materials to Grade 1 comprising fines materials of a size of at most about 5 mm and Grade 2 comprising fines materials of a size larger than about 5 mm; and at least one of: A) bio-oxydating organic contaminants of the Grade 1; by adding and mixing organic amendment under controlled temperature, nutrients content and water content conditions and monitoring a content of organic contaminants until the content of organic contaminants stops decreasing; and B) composting the Grade 1; by adding and mixing organic amendment under controlled temperature, nutrients content and water content conditions, and monitoring pathogens content and respiration rate; and stopping the addition of organic amendment upon detection of absence of pathogens at a predetermined respiration rate.

A method of valuation of raw fines materials, comprising selectively screening, biotreatment or composting of raw fines materials or selection as fillers in composites. The method comprises screening the raw fines materials to Grade 1 comprising fines materials of a size of at most about 5 mm and Grade 2 comprising fines materials of a size larger than about 5 mm; and at least one of: A) bio-oxydating organic contaminants of the Grade 1; by adding and mixing organic amendment under controlled temperature, nutrients content and water content conditions and monitoring a content of organic contaminants until the content of organic contaminants stops decreasing; and B) composting the Grade 1; by adding and mixing organic amendment under controlled temperature, nutrients content and water content conditions, and monitoring pathogens content and respiration rate; and stopping the addition of organic amendment upon detection of absence of pathogens at a predetermined respiration rate.

Provided is an insolubilizing material for a specific toxic substance useful for insolubilizing 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. The insolubilizing material, for a specific toxic substance, is used in a manner 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 comprises an amorphous aluminum compound or a derivative thereof as a main component. The insolubilizing material functions as a solidifying material. The insolubilizing material also comprises gypsum obtained by adding and mixing, to the gypsum, the amorphous aluminum compound or the derivative thereof in a range from 0.5 to 60 mass parts relative to 100 mass parts of the gypsum. A method for improving soil using the insolubilizing material is also disclosed.

Provided is an insolubilizing material for a specific toxic substance useful for insolubilizing 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. The insolubilizing material, for a specific toxic substance, is used in a manner 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 comprises an amorphous aluminum compound or a derivative thereof as a main component. The insolubilizing material functions as a solidifying material. The insolubilizing material also comprises gypsum obtained by adding and mixing, to the gypsum, the amorphous aluminum compound or the derivative thereof in a range from 0.5 to 60 mass parts relative to 100 mass parts of the gypsum. A method for improving soil using the insolubilizing material is also disclosed.

The present invention discloses a method for synergistic stabilization/solidification of red mud and phosphogypsum. The method includes: grinding and mixing red mud and phosphogypsum, adding deionized water, uniformly stirring the mixture to prepare slurry, adjusting a pH value of the slurry to 7.5-8.5, adding a conditioner and conducting stirring, adding a stabilizer and an anti-permeability agent, uniformly stirring the mixture to obtain a gel product, and conducting solidification for 12-24 h to solidify the red mud and phosphogypsum, to obtain a red mud-phosphogypsum solidified material. In the present invention, the neutralization reaction between acidic ions in phosphogypsum and basic ions in red mud is adopted to reduce a pH value of the red mud and a transfer capability of pollutants in waste residues; synergistic solidification processing is conducted on two types of solid wastes: red mud produced in the aluminum smelting industry and phosphogypsum produced in the phosphorus chemical industry.

The present invention discloses a method for synergistic stabilization/solidification of red mud and phosphogypsum. The method includes: grinding and mixing red mud and phosphogypsum, adding deionized water, uniformly stirring the mixture to prepare slurry, adjusting a pH value of the slurry to 7.5-8.5, adding a conditioner and conducting stirring, adding a stabilizer and an anti-permeability agent, uniformly stirring the mixture to obtain a gel product, and conducting solidification for 12-24 h to solidify the red mud and phosphogypsum, to obtain a red mud-phosphogypsum solidified material. In the present invention, the neutralization reaction between acidic ions in phosphogypsum and basic ions in red mud is adopted to reduce a pH value of the red mud and a transfer capability of pollutants in waste residues; synergistic solidification processing is conducted on two types of solid wastes: red mud produced in the aluminum smelting industry and phosphogypsum produced in the phosphorus chemical industry.

A design and construction method for using modified phosphogypsum in a roadbed and slope, where the method includes preparing a phosphogypsum-containing roadbed mixture, setting moisture content of the roadbed mixture, preparing a phosphogypsum-containing slope mixture, and construction of a roadbed and slope. The preparation of the phosphogypsum-containing roadbed mixture includes 90 parts by weight of phosphogypsum and 10 parts by weight of cement, and uniformly mixed and stirred to obtain a base material mixture; and 2-4 parts by weight of sodium silicate is dissolved in water, and the obtained solution is added to the base material mixture to obtain the phosphogypsum-containing roadbed mixture. The design and construction method are simple, can satisfy roadbed strength and rebound modulus requirements, and can be widely applied to filling-deficient areas with a high yield of phosphogypsum solid wastes.

A design and construction method for using modified phosphogypsum in a roadbed and slope, where the method includes preparing a phosphogypsum-containing roadbed mixture, setting moisture content of the roadbed mixture, preparing a phosphogypsum-containing slope mixture, and construction of a roadbed and slope. The preparation of the phosphogypsum-containing roadbed mixture includes 90 parts by weight of phosphogypsum and 10 parts by weight of cement, and uniformly mixed and stirred to obtain a base material mixture; and 2-4 parts by weight of sodium silicate is dissolved in water, and the obtained solution is added to the base material mixture to obtain the phosphogypsum-containing roadbed mixture. The design and construction method are simple, can satisfy roadbed strength and rebound modulus requirements, and can be widely applied to filling-deficient areas with a high yield of phosphogypsum solid wastes.