Pulverised fuel ash

Brown, J., Ray, N. J. Ball, M. 1976. The disposal of pulverised fuel ash in water supply catchment areas. Water Resources, 10, 1115-1121. 

Lee, S. Spears, D. A. 1997. Natural weathering of pulverised fuel ash and porewater evolution. Applied Geochemistry, 12, 367-376. 

Lee, S. Spears, D. A. 1998. Potential contamination of groundwater by pulverised fuel ash. In Mather, J., Banks, D., Dumpleton, S. Fermor, M. (eds) Groundwater contaminants and their Migration. Geological Society of London, Special Publications, 128, 51-61,... 

Two typical sets of pressure measurement data for the vertically down and vertically up sections of pipeline are presented in Fig. 2. This shows the location of the pressure tappings and their proximity to the various bends in the pipeline. The data relate to the pneumatic conveying of a fine grade of pulverised fuel ash. Five different bulk particulate materials were investigated in the research programme, the other four being barytes, bentonite, cement and fluorspar. All five materials were capable of being conveyed in dense phase and hence at low velocity. 

Fig. 2. Pressure gradient results for a fine grade of pulverised fuel ash.

Fig. 6. Conveying characteristics for pulverised fuel ash in 81mm bore pipeline.

Fig. 10. Pressure gradient for pulverised fuel ash in 81 mm bore vertically down pipeline.

C-S-H = poorly crystalline or amorphous calcium silicate hydrate of unspecified composition. Ggbfs = ground granulated blast furnace slag. Hep = hardened cement paste. Pfa = pulverised fuel ash (fly ash). 

Artificial hydraulic limes consist mainly of calcium hydroxide, calcium silicates and calcium aluminates. They are produced by blending suitable powdered materials, such as natural hydraulic limes, fully hydrated air limes and dolom-itic limes, pulverised fuel ash, volcanic ash, trass, ordinary Portland cement and blast furnace slag. 

Pozzolanic is used to describe materials, which, like pozzolana, contain reactive silica, and which, when mixed with quicklime and water, set to a hard mass. They include pulverised fuel ash, trass and burnt shale. 

Fly ash. Fly ash (also called pulverised fuel ash, PFA) is a by-product of the combustion of coal powder in thermoelectric power plants. It consists of very fine and spherical particles (dimensions from 1 to 100 pm and specific surface area of 300 to 600 m /kg) that are collected from exhaust gases with electrostatic or mechanical filters. Its composition depends on the type of coal it derives from the most common PFA is mainly siliceous. Because of the high temperature at which it is formed, it subsequently undergoes rapid cooling so that its structure is mainly amorphous (glassy) and thus reactive. 

Raask, E. P. J. Street, 1978. Appearance and pozzolanic activity of pulverised fuel ash. Unpublished proceedings of a Conference on Ash Technology and Marketing. London 22-27, October 1978. 

Soil stabilisation is the process of improving the engineering properties of the soil to increase its bearing capacity and hence its strength. The process involves the use of hydraulic binders such as cement, lime, lime/cement mix and pulverised fuel ash often with lime or blast furnace slag by itself or mixed with cement. This is known as additive stabilisation or chemical stabilisation. In all cases, the hydraulic additives intermingle with the soil material at the project site. Additive stabilisation rarely takes place away from the project site. 

The choice between the types of additive to use for stabilisation depends almost exclusively on the plasticity of soil material. For a soil material with low to medium plasticity, a cement additive may be used, while lime additive is used for medium- to high-plasticity soils. Pulverised fuel ash, normally with lime, is used in soils with little or low plastic fines. 

The cement used for the production of concrete is the common cement (Portland) or cement with fly ash. The cement should be in compliance with national specifications. For Europe and the United States, the relevant specifications for cement are the following CEN EN 197-1 (2011) and CEN EN 450-1 (2012) if with pulverised fuel ash, and CEN EN 197-2... 

Pulverised fuel ash, sawdust, spent lime and many other waste products can and have been used in some apphcations usually where a rou separation is required. Other eciahy prepared solid powder materials such as hydrated magneaum silicate, hydrated calcium silicate, bentonite, fuller s earth, or activated carbon are used in some applications piinc ally because of their adsorptive properties but they may also act as a filter aid in the separation of the particulate solids fi om the liquid. 

The typical chemical composition of pozzolanic materials such as pulverised fuel ash (PFA) and ground granulated blast furnace slag (GGBS) is well understood and their use as cement replacements is well-established in construction and concrete technology. Figure 15 compares the chemical composition of the waste materials used in this project and commonly used cementitious materials (OPC, GGBS and PFA). 

In iiny urban environment, the sources of trace-element contamination are manifold. As we have seen in the previous chapter, fallout from atmospheric pollution and wind-blown dusts are important sources whose effects are concentrated in urban and industrial areas. There is also incidental contamination resulting from the corrosion of metal objects and from the accidental dispersion of refuse and litter, and there is contamination resulting from the deliberate addition of waste products to the soil, such as soot, cinders, pulverised fuel ash, sewage sludge, municipal compost, or even untreated domestic rubbish. 

E.W.F. Gillham, Land Restoration with Pulverised Fuel Ash - The Besthorpe... 

This paper concerns the development of a model to predict the flow of bulk materials capable of the moving-bed type of dejise phase steady-state flow. This is a mode of flow that can be achieved by a number of industrially important materials including cement, pulverised fuel ash (pfa), barytes, polyethylene powder and flour. Figure 1 illustrates the modes of flow that can be achieved by such materials at various conveying gas velocities. It should be noted that the mode of flow, presented at the bottoms of Fig. 1, has time dependent behaviour. 

The utilisation of P.F.A. (pulverised fuel ash) as a filler in rigid polyurethane insulation foams... 

The use of Pulverised Fuel Ash (PFA) as a filler for low density polyurethane insulation foams has been evaluated. The chemical and physical interaction of PFA and polyurethane were investigated. The mixing characteristics of PFA lyurethane was examined. PFA/polyurethane foams were tested to see if their properties were within the... 

Pulverised Fuel Ash (PFA)—For the propose of the study a PFA sample known as "Finite PG" was used. This was supplied by Fillite (Rimcom) Limited, Cheshire, England. The properties of this sample are given in Table 1. 

HODD K.A., DAVIES L.C.B. and SOTHERN G.R.— Dept. of Materials Technology, Branei University, U.K.—Pulverised Fuel Ash its use as a filler for polyolefins. 

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