Abstract: A cementitious mixture includes hydraulic cement, fly ash, and an effective amount of unfired nature finely divided material, such as a clay, containing at least about 35% alumina, to accelerate the early strength of a mix. A method of accelerating early strength in a cementitious mix comprises the adding of alumina in the form of an unfired raw material, such as clay, in an effective amount in such mix.

Abstract: A method of treating fly ash which has a moisture content and which also has a high carbon particle content includes the steps of heating the fly ash to a temperature sufficient to break the bond between the fly ash and the carbon particles caused by the moisture content, applying the heated fly ash in a relatively thin layer to the surface of a belt-type conveyor and subjecting the layer of heated fly ash to the effects of an electrostatic charging zone while repeatedly mechanically rearranging the orientation of the fly ash particles in the zone for causing the carbon particles to take a charge and become attracted to an electrode so that the same may be separated from the layer. Apparatus for separating carbon particles from fly ash includes a generally horizontal conveyor, and a hopper which applies fly ash to be treated in a layer on the surface of a conductive belt.

Abstract: A cementitious mixture includes hydraulic cement, fly ash, and an effective amount of unfired nature finely divided material, such as a clay, containing at least about 35% alumina, to accelerate the early strength of a mix. A method of accelerating early strength in a cementitious mix comprises the adding of alumina in the form of an unfired raw material, such as clay, in an effective amount in such mix.

Abstract: Methods and apparatus for reducing the carbon content of fly ash are disclosed. The fly ash is subjected to an inclined surface having first and second vibratory sources for respectively moving the fly ash from the elevated end of the incline to the lower end and to disaggregate and stratify a high carbon fraction from an enhanced fly ash fraction. The second vibratory source, in combination with the inclined surface, separates the lighter, high carbon fraction while the heavier enhanced fly ash fraction travels toward the lower end of the incline. An air jet and associated vacuum draft pull the high carbon fraction from the incline, leaving the enhanced fly ash portion for use, after removal from the surface, as an example, as acceptable mineral admixture for use in Portland Cement concrete.

Abstract: Municipal solid waste ash is utilized in the manufacture of an aggregate and is processed to form a cold bonded pellet which, when tested by means of TCLP leaching extraction tests using TCLP No. 2 extraction fluid, does not exceed the 1990 limits for the RCRA priority heavy metals. The pellets may be surface coated with defined agents to seal the pellet or to provide properties which enhance the use of the pellet in either asphaltic or cement concrete mixes.

Abstract: A landfill cell for the containment of MSW ash is defined in part by a depression in the ground bounded by a leachate impervious liner which forms the bottom and side walls of the cell, for continuous long-term protection of underyling and contiguous aquifers from contamination by heavy metals. The cell has a base layer of a natural cationic material in the form of amended and compacted lignite, which may be enhanced by the addition of about 6 to 12% lime by weight, extending in overlying relation to the liner along the bottom and along the side walls. An overburden of the waste ash material rests on the base layer, and at least one additional layer of amended lignite is positioned immediately above the first overburden, and at least one additional layer of the waste material overburden rests on the additional layer of cationic material. The lignite is ground to a small particle size of about 0.1 mm to 2.0 mm in size and has a CEC value of about 120 meq/100 g when enhanced by the addition of lime.

Abstract: A process is disclosed for forming lightweight aggregate pellets having a density of less than about 60 lbs./ft..sup.2. The first step of the process is to form an admixture which includes fly ash, cement and filler. By weight percent of the admixture formed, the admixture includes greater than 60% fly ash, 1-25% cement and 1-10% filler. Water and a chemical accelerator are added to the admixture in a pelletizing device. By weight percent of the aggregate formed, about 1 to 18% water is added and between about 0 and 3% chemical accelerator is added by weight of the cement used in the admixture. The aggregate pellets are then removed from the pelletizing device and cured with an oxygen containing gas, such as air, at a temperature of less than about 300.degree. F.

Abstract: A light-weight aggregate, for use in production of light-weight structural products, composed of a self-hardening fly ash, a surfactant foam, and optionally an accelerator and additives. The self-hardening fly ash is preferably class C fly ash formed by the combustion of sub-bituminous coal from the Power River Basin. The surfactant foam is preferably an anionic sulfate surfactant foam. The accelerator is preferably an extract of silica fume dust. The additives may include magnesium and boron compounds, other fly ashes, light-weight fillers, polymers, cement and magnesium silicate and like materials.

Abstract: Solid, leach-resistant bodies are formed from aqueous heavy metal sludge and fly ash formed in the combustion of subbituminous coal from the Power River Basin by slurrying the sludge with an amount of fly ash equivalent to between about 20 wt. % and about 70 wt. % based on the weight of the slurry, wherein the initial liquid content of the slurry is such that the slurry will harden into a body having a 7-day compressive strength of at least about 250 psi, and allowing the slurry to harden.

Abstract: A wet process is disclosed for the beneficiation of electrostatic fly ash to provide therefrom a series of products which have higher commercial value than the raw fly ash, including a carbon concentrate, cenospheres, an iron concentrate, an enhanced pozzolan, and an inert mineral filler.

Abstract: A method of dewatering mineral slimes by adding fly ash and then a polyelectrolyte and blending slowly and thoroughly. The clear water supernatant may be drawn off from the sedimented coagulated solids. The coagulated solids may be further dewatered or treated in ecologically beneficial ways.