Impact of weathering and aging on a LIMB ash stockpile material

摘要

A 1,500 ton temporary storage pile of water conditioned LIMB (Lime Injected Multistage Burner) ash by-product from the Ohio Edison Edgewater plant Lorain, OH was constructed in July, 1991 at a coal company near New Philadelphia, Ohio. This stockpile was created for dry FGD by-product material to be held in reserve for a land application uses field demonstration. High volume, beneficial uses of dry FGD by-products, such as for mine reclamation and embankment stabilization, will require temporary stockpiling of the by-product. Purpose for constructing this pile was to study changes with time in the LIMB by-product material when exposed to weathering. This by-product material was studied over a 2 1/2 year period. The water to control fugitive dust was added in the ash conditioner at the power plant while being loaded into dump trucks. Amount of water normally added in the conditioning process is close to the optimum moisture content of 40--50 % (dry weight basis), to construct a compacted road embankment or road base. Four environmental operating permits required for construction of the storage pile were obtained, three from Ohio EPA (air, water and solid waste), and one from the Ohio Division of Reclamation (revised reclamation area permit). There was no significant environmental impacts from storm runoff or leachate water from the LIMB ash stockpile during the initial 18 month period through December, 1992. After 2 1/2 years of storage, the potential value of the LIMB material for use as a road embankment material or soil conditioner has declined significantly. Ettringite formation occurs. Aging allows the expansive reaction to take place before its potential use as compacted structural fill or embankment.