Aerosols mineral processing

Many of the applications of colloid and interface science to the mining and mineral processing industry can be found in the hydrotransport, flotation and tailings processes. Although suspensions feature prominently in each of these, a range of emulsions, foams, suspensions and aerosols can be found in this industry. Some examples are given in Table 10.1. 

Table 10.1 Some emulsions, foams, suspensions and aerosols in mineral processing...

Particle size distributions of smaller particles have been made using electrical mobility analyzers and diffusion batteries, (9-11) instruments which are not suited to chemical characterization of the aerosol. Nonetheless, these data have made major contributions to our understanding of particle formation mechanisms (1, 1 ). At least two distinct mechanisms make major contributions to the aerosols produced by pulverized coal combustors. The vast majority of the aerosol mass consists of the ash residue which is left after the coal is burned. At the high temperatures in these furnaces, the ash melts and coalesces to form large spherical particles. Their mean diameter is typically in the range 10-20 pm. The smallest particles produced by this process are expected to be the size of the mineral inclusions in the parent coal. Thus, we expect few residual ash particles smaller than a few tenths of a micrometer in diameter (12). 

Atmospheric transport processes provide an effective mechanism by which mineral aerosol is transported over the entire globe. 

These are produced, for example, during incomplete combustion processes, and mineral extraction and processing. They can be organic or inorganic, and can form aerosols in which hydrocarbons may be present (these hydrocarbons may have toxic effects). Examples include coal dust and asbestos. 

Is an oil-soluble emulsifier for mineral oils, fatty oils, softeners. It is used as a cutting oil emulsifier, a solvent emulsifier in metal cleaners and degreasers, a W/O emulsifier for consumer pesticide aerosols, and as a lubricant component in textile processing. It also softens and lubricates leather during tanning. 

Hand,. L., Mahowald, N. M., Chen, Y., Siefert, R. L., Luo, C., Subramaniam, A., and Fung, I. (2004). Estimates of atmospheric-processed soluble iron from observations and a global mineral aerosol model Biogeochemical implications. J. Geophys. Res. Atmos. 109, D17205. 

Song C. H. and Carmichael G. R. (1999) The aging process of naturally emitted aerosol (sea-salt and mineral aerosol) during long range transport. Atmos. Environ. 33, 2203-2218. 

Particulate emissions are by-products of fuel combustion, industrial processes, and motor vehicles and are believed to have a significant potential for causing adverse health effects. Carbonaceous material present in atmospheric aerosols is a combination of elemental carbon and organic and inorganic compounds. Particulate matter may also consist of fly ash, minerals, or road dust and contain traces of a number of heavy metals. Population-based studies have consistently found that the association between adverse respiratory effects and particulate concentrations occurs in a number of regions throughout the United States. This association is strongest for PM]o and PM2.5 indices (particulate matter less than 10 and 2.5 pm in diameter, respectively). The observed adverse effects include increases in total mortality, mortality due to respiratory and cardiovascular causes, chronic bronchitis, and hospital visits and admissions for asthma. Elderly or unhealthy individuals and infants appear to comprise subpopulations that are most sensitive to the adverse health effects of PM. 

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