초록 ▼

Strong dense shaped articles such as pellets suitable for use as gravel substitutes are produced by the described method from solid fly ash-containing water materials obtained by a lime based dry scrubbing flue gas desulfurization operation. In this method the dry ash-containing waste powder, which

Strong dense shaped articles such as pellets suitable for use as gravel substitutes are produced by the described method from solid fly ash-containing water materials obtained by a lime based dry scrubbing flue gas desulfurization operation. In this method the dry ash-containing waste powder, which also contains calcium sulfite or sulfate reaction products and unreacted lime, is first uniformly contacted with a critical amount of water and then immediately compacted at a critical compaction ratio to provide a handleable green body in which the fly ash particles are positioned with respect to one another so that the interstitial spaces are sufficient to accommodate the volumetric changes in wthe cementitious materials without any deleterious expansion of the article as the article is cured.

대표청구항 ▼

A process for preparing a dense shaped article, said article comprising fly ash particles bonded together by cementitious reaction products, said process comprising the steps of: (a) providing a substantially dry fly ash-containing powder obtained from the dry scrubbing of fly ash-containing flue ga

A process for preparing a dense shaped article, said article comprising fly ash particles bonded together by cementitious reaction products, said process comprising the steps of: (a) providing a substantially dry fly ash-containing powder obtained from the dry scrubbing of fly ash-containing flue gas with lime in a spray drying system, said fly ash-containing powder comprising fly ash in intimate admixture with microparticulate crystallites of scrubber reaction materials selected from the group consisting of calcium sulfite, calcium sulfate, hydrates of calcium sulfite and calcium sulfate, calcium oxide, calcium hydroxide and mixtures thereof; (b) uniformly contacting said fly ash-containing powder with a predetermined amount of water to produce a powder/water mixture; (c) forming said powder/water mixture into a shaped article by confined compaction at a predetermined compactive effort sufficient to provide a handleable green body; said predetermined amount of water being selected as at least that amount sufficient to satisfy the short term hydration demands of said powder and further selected in combination with a selected predetermined compactive effort to produce a green body having an uncured dry density in the range of from about 95 to about 140 pounds per cubic foot and wherein the interspatial voids between the fly ash particles in said green body are sufficient to accommodate the subsequently formed cementitious reaction products without deleterious expansion of the article; and (d) curing said green body product in a moist atmosphere to form a shaped article bonded by said cementitious reaction products.