Waste metal conversion process and products

In a process for producing a finely divided filler material from an aqueous waste solution containing at least one metal capable of reaction to form insoluble hydroxide and sulfide compounds, and selected from the group consisting of copper, iron, nickel and chrome, the steps comprising:

• (a) effecting reaction in said solution to produce an aqueous sludge comprised of an insoluble hydroxide and sulfide precipitate of said metal;
• (b) settling said precipitate and decanting and filtering said sludge to remove water therefrom so as to produce a concentrate containing less than about 60 weight percent of water;
• (c) admixing with said concentrate about 10 to 40 percent, based upon the weight thereof, of a basic fixative comprised of calcium oxide, said fixative being capable of exothermic hydration and combination with said precipitate, ultimate autogenic temperatures of at least about 60.degree. Centigrade being attained during said hydration reaction, with the amount of free water being reduced by evaporation as well as through hydration of said fixative to thereby produce less than about 25 weight percent in said concentrate;
• and
• (d) drying said concentrate to produce a homogeneous, particulate filler material, said drying step including a substantial period of dormancy prior to said fixative admixing step (c), and including final phases effected by introducing thermal energy from an external source into said admixture, thereby heating said admixture to a temperature of about 120.degree. to 200.degree. Centigrade and reducing said free water content in said filler material to less than about three weight percent.

In a process for producing a finely divided filler material from an aqueous waste solution containing at least one metal capable of reaction to form insoluble hydroxide and sulfide compounds, the steps comprising:

• (a) introducing sodium hydroxide and sodium sulfide into said solution to produce an aqueous sludge comprised of a precipitate of said metal;
• (b) removing water from said sludge to produce a concentrate containing less than about 60 weight percent water;
• (c) admixing with said concentrate about 10 to 40 percent, based upon the weight thereof, of a basic fixative comprised at least 50 percent by weight of calcium oxide, capable of exothermic hydration and combination with said metal percipitate and effecting hydration reaction there between;
• and
• (d) drying said concentrate to produce a homogeneous, particulate filler material containing less than about 25 weight percent of water.

In a method for producing an asphalt paving mix, the steps comprising:

• (1) producing a finely divided filler material from an aqueous waste solution containing at least one metal capable of reaction to form an insoluble hydroxide and sulfide precipitate, by a process including the substeps of:
• (a) effecting reaction in said solution to produce an aqueous sludge comprised of an insoluble hydroxide and sulfide precipitate of said metal,
• (b) removing water from said sludge to produce a concentrate containing less than about 60 weight percent of water,
• (c) admixing with said concentrate about 10 to 40 percent, based upon the weight thereof, of a basic fixative comprised at least 50 percent by weight of calcium oxide, capable of exothermic hydration and combination with said metal precipitate and effecting hydration reaction therebetween;
• and
• (d) drying said concentrate to produce a homogeneous, particulate filler material containing less than about 25 weight percent of water;
• (2) combining said filler material with asphalt aggregate material to provide an aggregate mixture containing about 5 to 25 weight percent of said filler material;
• and
• (3) admixing hot asphalt binder with said aggregate mixture to provide said paving mix.