http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Review of fly ash as a soil amendment
Jeffrey Skousen,양재의,Jin-Soo Lee,Paul Ziemkiewicz 한국자원공학회 2013 Geosystem engineering Vol.16 No.3
Worldwide, about 500 million tonnes of coal combustion by-products (CCPs) are produced annually. Fly ash constitutes 70% of the by-products generated, and these ashes vary in their composition and properties based on the boiler type and the gas emission control system. Fly ashes are used as fill material, alkaline amendments, cement, and grout material. Because of high-soluble salt content and leachable macro and micronutrients, they can be used as a soil amendment to replace fertilizer and lime. Alkaline fly ashes can be added in large quantities to neutralize acidity and raise pH associated with acid soils. Care should be taken to ensure that sufficient quantities of alkalinity are added so that fly ash does not become acid stripped, thereby releasing high levels of elements that can become toxic. Fly ashes can also improve soils with poor physical properties. Coarse-textured or rocky soils can be amended with fly ash to increase the silt- and sand-sized fractions, which help in aggregation, infiltration, and water-holding capacity. Research has demonstrated positive benefits of fly ash addition for improving soil properties and in increasing crop yields. Results also documented no detrimental effects with application of fly ashes to acid, neutral, or saline-sodic soils.
Use of Coal Combustion By-Products in Mine Reclamation: Review of Case Studies in the USA
Jeffrey Skousen,Paul Ziemkiewicz,양재의 한국자원공학회 2012 Geosystem engineering Vol.15 No.1
With the continued use of coal to generate electricity for the world’s power needs, coal combustion by-products (CCPs) will be produced in greater quantities during the ensuing decades. About 130 million tons of CCPs are produced annually from the 600 coal-fired power plants currently operating in the USA, with estimates of 500 million tons produced worldwide. Five major types of CCPs exist: bottom ash, boiler slag, fly ash, fluidized bed ash, and flue gas desulfurization ash. Bottom ash does not generally constitute a disposal problem because it is extensively used as aggregate fill material for construction projects, filler in construction materials (wall board and dry wall), and deicing solids for roads. Boiler slag is used for similar purposes as bottom ash, but it can be used as a glassy grit material for sand blasting. Fly ashes constitute 70% of the by-products generated and these ashes are produced in several ways in a power plant depending on the boiler type and the emission control system employed at the power plant. These fine-textured ash materials may be dry fly ash from conventional coal-fired boilers, dry ashes collected in flue-gas desulfurization (FGD) or other collection devices (bag houses or scrubber filters), or they may be collected in wet scrubber systems producing a fly ash slurry. Coal combustion by-products (CCBs) can be beneficially used as: 1) an alkaline seal or fill material to contain acid producing materials and to prevent the formation of acid mine drainage; 2) an agricultural amendment to create artificial soil on abandoned mine lands where native soils are not available; 3) an alkaline amendment added to spoils to neutralize acid producing materials in the spoil; 4) a flowable fill that seals and stabilizes abandoned underground mines to prevent subsidence and the production of acid mine drainage; and 5) a non-toxic fill material for final pits within the spoil area to reduce reclamation costs. Case studies in this paper demonstrate that CCPs can be used to improve reclamation, revegetation and water quality on reclaimed areas. Results to date have shown the effective neutralizing capacity of these ashes and stabilization of reclamation sites.