44 THE IRON ORE DISTRICT OF EAST TEXAS. 



SUGAR REFINING. 



Lately lignites have been very advantageously used in the purification of 

 sap in sugar factories, supplanting the costly bone black. It is claimed that 

 in many instances it is sufficient to filter the sap over the coal. In others, 

 however, it is necessary to prepare the lignites for use. The coal is thor- 

 oughly dried, converted into a fine powder, well mixed with the sap, and 

 the purified liquid pressed or filtered from the mass. The lignite, after hav- 

 ing served for this purpose, can be used as fuel. 



FERTILIZERS. 



The use of brown coal refuse in the manufacture of artificial manure has 

 been mentioned before. 



FUEL. 



Far superior in importance, however, to any utilization of brown coal yet 

 treated of, especially with reference to Texas lignite, is its use as burning 

 material in form of coke or briquettes. The fortunate association of lignites 

 with the iron ores of the eastern part of the State makes them one of the most 

 valuable mineral products the State possesses, and the time is not far distant 

 when their high economic value in Texas iron smelters will be fully realized. 

 On this account the following pages will treat more fully of the subjects enu- 

 merated, though, like the foregoing, they are intended only to be preliminary 

 to a more exhaustive discussion, with special reference to modern improve- 

 ments in the manufacture of coke and briquettes and their utilization in iron 

 smelters, to be made in a future report. 



COKE. 



The history of coke dates back for a number of years, and the principle 

 features of its rational manufacture have been long known. It was obtained 

 by the dry distillation of coal when the production of illuminating gas was 

 the object of the process. It has also been obtained in various other branches 

 of the coal industry, and large establishments have been erected to obtain it. 



It may not be altogether uninteresting briefly to review the early history 

 of coking lignites, which dates back more than fifty years. As a matter of 

 course, the first experiments were crude and the results not very satisfactory. 

 The coking of the material was effected in those early times in coal kilns, that 

 is, the brown coal was heaped up in piles, containing sometimes not less than 

 sixty tons of coal, covered with earth. The coke obtained by this method 

 was generally of the same quantity and quality, about forty per cent of small 

 pieces of considerable hardness. These experiments were followed about 

 1 860 by others conducting the coking in closed iron chambers or brick ovens, 

 and the process further improved by cementing the lignites with tar before 



