Synthetic aggregate and landfill method
AssigneeConversion Systems, Inc.
InventorsCharles L. Smith, John J. Juzwiak
Life of this patent
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Abstract
An abrasion resistant synthetic aggregate made from an intimately intermixed combination of lime, fly ash and sulfate/sulfite sludge (e.g. FGD sludge), mixed to the point where the mixture is nearly optimum density and compressible or non-compressible and plastic. This mixture is placed in a landfill. After a relatively brief cure period, the landfill is ripped and the material is crushed and graded. The aggregate, which in some instances may qualify as a light weight aggregate, has a Los Angeles Abrasion Resistance of less than 60%, and may in some cases be less than 50% (medium particles passing) according to that test.
Claims14
A method of making an abrasion-resistant cementitiously hardened synthetic aggregate by
- a) forming an intimate, initially non-compressible reactant mixture by intense mixing of a material combination comprised of 2.5-6% lime, at least 33% fly ash and at least 20% alkaline earth metal sulfate/sulfite sludge solids (all on a dry weight basis), with water in an amount no less than 5% below that necessary to form an optimum density mixture with the solids in the mixture,
- b) placing said intimate, initially non-compressible reactant mixture in a landfill in a layer of sufficient thickness to be 8 to 24 inches thick after the first compression pass of step d), below,
- c) waiting a sufficient time to permit a water-consuming reaction to occur in said mixture and to render said intimate, initially non-compressible reactant mixture compressible,
- d) applying pressure to said mixture rendered compressible by step c) by traversing the surface thereof with a means for applying compactive pressure thereto, in a sequence of passes to cause a significant increase in density from pass to pass to form a densified mixture,
- e) permitting said densified mixture to harden as a monolithic mass over a cure period at least equivalent to 28 days at 73.degree. F.,
- f) ripping said cured monolithic material into subdivisions thereof, and
- g) collecting, crushing and screening said subdivisions into gradations suitable for use as aggregate.
A method of making an abrasion-resistant cementitiously hardened synthetic aggregate by
- a) forming a reactant mixture by intense mixing of a material combination comprised of 2.5-6% lime, at least 33% fly ash and at least 20% alkaline earth metal sulfate/sulfite sludge solids (all on a dry weight basis), with water in an amount no less than 5% below that necessary to form an optimum density mixture with the solids in the mixture,
- b) placing said reactant mixture in a landfill in a layer of sufficient thickness to be 8 to 24 inches thick after application of pressure according to step c), below,
- c) applying compactive pressure to said mixture by traversing the surface thereof with a means for applying compactive pressure thereto,
- d) waiting a sufficient time to permit a water-consuming reaction to occur,
- e) and then applying further compactive pressure to said mixture by traversing the surface thereof with a means for applying compactive pressure thereto, in a sequence of passes to cause an increase in density from pass to pass to form a densified mixture,
- f) permitting said densified mixture to harden as a monolithic mass over a cure period at least equivalent to 28 days at 73.degree. F.,
- g) ripping said cured monolithic material into subdivisions thereof, and
- h) collecting, crushing and screening said subdivisions into gradations suitable for use as aggregate.
Dependencies are inferred from the claim text.