Mistura de carvões para coque metalúrgico

Abstract

This study was developed by the Project Department of the BNDE at the request of the Civil 'Cabinet of the Presidency of the Republic, as an information which would provide the Executive with a background for appreciating a Project under discussion at the Chamber of Deputies, establishing compulsory 40% minimum consumption of domestic coal by brazilian smelting plants and coke ovens. The study starts by examining the process of using coal and preparing coke in iron and steel works, and goes on with an analysis of the coking coals mined in Santa Catarina, the only ones used at present by brazilian plants for coke production, mixed with foreign coals. On account of their high ash and sulfur content, Santa Catarina coals have to be processed to obtain commercial grades — an operation that is performed at the central washing plant of the Cia. Sideritrgica Nacional at Capivari, in that state, and yields the following average results: 35% metallurgical coal with an average content of 18% ash and 1.8% sulfur; 31% coarse and fine steam coal, with 30% ash and 2.6% sulfur; and 30% pyrites rejects, with 21% sulfur. The disposal of steam coal and rejects is a problem of major importance as regards increasing the output of metallurgical coal, owing to the gradual reduction in the use of the former by railroads and shipping, and the absence of any chemical plants working with pyrites residues. Furthermore, the consumption of steam coal in thermo-electric power plants is still small in Brazil. A study is then made of the process by which national and foreign metallurgical coals are mixed in brazilian plants to produce suitable coke, and various difficulties of a technical and economic nature are shown to stand in the way of increasing the percentage of domestic coal in this mixture, as proposed in the bill before the National Congress. Finally, a number of steps are suggested that might be taken with a view to developing the brazilian coalmining industry.