Process for producing hardened materials from combustion ash of fluidized bed
AssigneeKawasaki Jukogyo Kabushiki Kaisha
InventorsSusumu Mitsuda, Yasunori Shibata, June Tatebayashi
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Abstract
The present invention relates to processes for producing a material usable as a suitable civil engineering and construction material by treating a combustion ash formed by the combustion of a fluidized bed comprising a coal as the fuel and limestone as a desulfurizing agent. In this process, quick lime contained therein is sufficiently slaked at first by addition of water and heat thus generated is released to prevent disintegration of the product, and then the product is subjected to atmospheric pressure steam treatment to obtain a product of high strength in a short time.
Claims8
A process for producing a hardened material from a fluidized combustion ash which comprises quicklime, which process comprises adding water to a combustion ash formed by combustion of a fluidized bed comprising a coal as fuel and limestone as a desulfurizing agent, the amount of water being added in two stages, wherein in the first stage the water is added in an amount sufficient to slake the quicklime in said ash but insufficient to form said hardened material;
- kneading the resultant mixture;
- in a second stage adding the remainder of the water necessary to form said hardened material;
- kneading the mixture to form granules having a diameter of mainly 0.5 to 50 mm;
- and treating the granules with steam at 40.degree. to 100.degree. C. under atmospheric pressure to obtain the hardened material.
A process for producing hardened materials, which comprises adding water to a combustion ash comprising quicklime formed by combustion of a fluidized bed comprising coal as fuel and limestone as a desulfurizing agent;
- kneading the resultant mixture;
- controlling the slump of the mixture at 0.5 to 10 cm;
- cutting the kneaded mixture into pieces when the penetration resistance thereof becomes in the range of 5 to 20 kg by a hydration reaction;
- curing the pieces at ambient temperature until the penetration resistance is increased to 30 kg or more;
- and treating the pieces with steam at 40.degree. to 100.degree. C. under atmospheric pressure;
- and wherein the water is added in two stages wherein in the first stage water is added in an amount sufficient to slake said quicklime in said ash but insufficient to form said hardened material;
- then in a second stage adding a remainder of the water necessary to form said hardened material, wherein said two stage water addition operates to prevent the formation of cavities and reduction of strength of the hardened material.
Dependencies are inferred from the claim text.