Oil agglomeration for fine coal refuse treatment

In summary, therefore, it would seem that the lack of progress with the commercialization of the oil agglomeration principle has been due to factors other than shortage of attempts or concepts. From the literature it would appear that these factors include: (1) The uneconomic use of the process as a competitor to froth flotation; (2) The use of capital intensive and high operating cost process equipment; (3) The low market value of coal fines relative to oil at the time of development; (4) The energy consumption and high wear rates associated with mixing. From the outset it was apparent that the development of a process at Broken Hill Proprietary (BHP) Co. Limited's Central Research Laboratories based on the oil agglomeration principle must satisfy a number of conditions. The most important of these conditions was that if economic viability were to be achieved, the high operating costs associated with the use of oil additions must be offset by other process advantages such as low equipment costs and environmental benefits. The problem then becomes one of striking a realistic balance between these two competing factors to arrive at the optimum financial return from the process. In the case of refuse material, amore » more favorable balance is achieved because in this circumstance the feed material to the process may be considered to be available at nil cost. As a result of this thinking, bench-scale experiments were commenced in 1975. The results of these experiments showed that agglomerates of suitable size and strength for collection by sieve bend screening could be obtained at relatively low energy inputs provided the oil phase was emulsified prior to injection in the coal slurry. After the pilot plant had demonstrated technical feasibility it was decided to proceed with the design and construction of a larger plant. (LTN)« less