Background Art The coal for use in a corex process is required larger than 8 mm in size. But large amounts of imported coal (maximum 60%) for use in the corex process comprises particles smaller than 8 mm in size. So imported coal can not be employed in the corex process but utilized just in the PCI or cokes process.

The characteristics of coal for use in the corex process are too limited to use the other processes. Therefore the ratio of coarse-particle coal should be increased and fine- particle coal should be treated appropriately to improve the efficiency of the corex process.

The method for aggregating fine-particle and feeding into corex is said to be the most useful among many methods for treating the fine-particle coal. For instances, sulfurous waste solution, starch or asphalt has been used as a binder in the aggregation process of fine-particle coal.

But the methods set forth above have been known that large amounts of a binder (10-20 weight %) should be utilized, which correspondingly leads to high cost for production. Other problems exist in the said methods. For example, a binder requires to be heated above the melting point and to be fused prior to the aggregation, and wetted fine-particle coal needs to be dried prior to the aggregation. The methods mentioned above cause the complicated aggregation process

Disclosure of Invention The present invention is based upon the discovery that the styrene-butadiene latex can be used as a binder in the aggregation process of fine-particle coal. In addition, the styrene-butadiene latex, which is water-based emulsion, can be used to bind inorganic materials, such as calcium chloride, clay, silicate.

This invention provides a method for decreasing the amounts of a binder used.

The invention also provides a method for lowering aggregation temperature to room temperature, and for aggregating wetted coal without any further dry process in the aggregation process of fine-particle coal.

In accordance with the present invention, the styrene-butadiene latex is utilized as a binder, more specifically, used in an amount of from about 0. 5% to about 5% by weight in the aggregation process of fine-particle coal.

The invention is described in more detail as set forth hereunder.

Since the styrene-butadiene latex is water-based emulsion, the styrene- butadiene latex is easily mixed with coal. In addition the styrene-butadiene latex can be employed to bind inorganic materials, such as calcium chloride, clay, silicate due to the double bond of butadiene in polymer which gives an adhesive force.

If the styrene-butadiene latex is used more than about 5 weight %, the compression strength will decrease owing to too much elasticity. If the styrene- butadiene latex is utilized under about 0. 5 weight %, aggregation will not occur.

Accordingly the styrene-butadiene latex requires to be used in an amount from about 0. 5% to about 5% by weight when mixed with fine-particle coal.

Since the styrene-butadiene latex is water-based emulsion, the wetted fine- particle coal can be aggregated without any further dry process.

A fine-particle coal and a binder should be mixed homogeneously and aggregated at a certain temperature. That is, the temperature of asphalt should be raised at about 110~130°C, but the styrene-butadiene latex can be used at about 0-5 0°C.

If desired, the curing accelerators, such as calcium chloride, aluminum sulfate, magnesium sulfate and hydrosilicofluoric acid can be utilized at a level of from about 0. 1% to about 2. 0% by weight during the aggregation to improve dry rate and initial strength and to facilitate curing.

The natural thickeners, such as methyl cellulose, carboxymethyl cellulose, starch, molasses, casein, and the synthetic thickeners, such as polyacrylic acid, polyvinyl alcohol, alkaline swelling emulsion, can be also added about 0. 1-2. 0% by weight to improve initial strength. The inorganic thickeners, such as bentonite, colloidal silica can be likewise added.

If desired, said curing agents and thickener can be employed in the aggregation process of fine-particle coal at the same time.

Best Mode for Carrying out the Invention The following examples illustrate the specific embodiments of the present invention.

EXAMPLE 1 The compression strength was evaluated when the styrene-butadiene latex was used as a binder in the aggregation process of fine-particle coal smaller than 2 mm in size.

The aggregated coal tested for the compression strength was prepared in accordance with the following procedure ; To fine-particle coal smaller than 2 mm in size, the solution of 100 weight parts of the styrene-butadiene latex with the weight % according to table 1, 400 weight parts of the de-ionized water was added and mixed homogeneously and then fed into the crucible. And it was followed by the aggregation step for 10 seconds in mould

maintained at approximately 25 C. Thereafter the aggregated coal was taken out of the mould and was stored.

Each aggregated coal with the different amount of weight % of the styrene- butadiene latex was tested for compression strength with the following time. The results were as follows.

Table 1 Compression strength (kg/cm') Sample latex 1 min 10 min 10 hours 100 hours I weight % 2. 5 2. 7 10. 3 270. 5 2 weight % 2. 9 3. 5 15. 2 303. 5 3 weight % 3. 2 3. 4 20. 1 310. 7 10 weight % 3. 0 3. 1 5. 6 32. 5 EXAMPLE 2 To fine-particle coal smaller than 2 mm in size, the solution of 100 weight parts of the styrene-butadiene latex with the weight % according to table 2, 1. 2 weight parts of methyl cellulose and 400 weight parts of the de-ionized water was added. The following steps were performed in the same way as the example 1. The results were as follows : Table 2 Compression strength (kg/cm) Sample latex 1 min 10 min 10 hours 100 hours 1 weight % 4. 5 9. 8 35. 2 294. 5 2 weight % 5. 9 12. 5 45. 3 327. 8 3 weight % 6. 8 15. 7 59. 7 332. 5 10 weight % 5. 6 6. 5 15. 3 29. 8 These results demonstrate that an increase in compression strength was obtained by the incorporation of methyl cellulose,

EXAMPLE 3 To fine-particle coal smaller than 2 mm in size, the solution of 100 weight parts of the styrene-butadiene latex with the weight % according to table 3, 0. 1 weight parts of calcium chloride and 400 weight parts of the de-ionized water was added. The following steps were performed in the same way as the example 1. The results were as follows : Table 3 Compression strength(kg/cm2) Sample latex 1 min 10 min 10 hours 100 hours 1 weight % 11. 3 17. 8 37. 6 305. 5 2 weight % 13. 2 19. 7 49. 7 332. 2 3 weight % 15. 4 23. 5 59. 5 345. 8 10 weight % 1 10. 9 17. 3 23. 5 27. 5 These results indicate that an increase in compression strength was obtained by the incorporation of calcium chloride, Industrial Applicability As described above, this invention has several advantages in that the amounts of a binder used can be decreased, aggregation temperature can be lowered to room temperature, and wetted coal can be aggregated without any further dry process in the aggregation process of fine-particle coal. Accordingly this invention can offer opportunities for reduced binder consumption in the aggregation process and for simplifying the complicated aggregation process and thus improved process economics.