A.L. Ottrey's scientific contributions

This chapter highlights different inorganic constituents present in Victorian brown coals. The ash forming constituents in Victorian brown coal can be divided into two groups: (1) minerals, which occur as discrete particles, principally quartz, kaolinite, and pyrite/marcasite and (2) non-mineral inorganics present as exchangeable cations on carboxyl groups and water soluble salts. The chapter presents the nature and mode of occurrence of the inorganic constituents, their distribution in the coal seams, and the chemical transformations they undergo during coal utilization. The nature of the inorganic ash-forming constituents in these coals, however, is such that they exert an important influence on the behavior of these coals during utilization. The transformation of the mineral and nonmineral inorganic species present in Victorian brown coal during its utilization in various processes depends on the relative concentrations of the individual species and the process conditions (including thermal history). The combustion of Victorian brown coal in pulverized fuel fired boilers results in the formation of fly ash and fireside ash deposits, mainly as a result of transformations sustained by the nonmineral inorganic species. A key role in the process of ash formation is that of sodium through the condensations of its vapor state species on either fly ash particles or heat transfer surfaces. The current and future areas of research related to inorganic constituents of Victorian brown coal include (1) the development of on-line methods of analysis, to provide detail of coal quality variations for process control, and (2) the influence of additives on the behavior of the coal in processes.