CHAPTER XLV. 

 SLAG BRICKS AND SLAG BLOCKS.* 



UNDER the names of "slag brick ", "slag tile ", "slag block ", "scoria 

 brick ", etc., two very different products have been included by various 

 writers. Both products are made from blast-furnace slag, but the two 

 classes differ so greatly in their methods of manufacture and properties 

 that it seems necessary to describe them separately. This has accord- 

 ingly been done, the names "slag bricks " and "slag blocks " being 

 supplied to the respective classes. As here used, the term "slag brick " 

 will be confined to those bricks, tiles, etc., which are made by mixing 

 slaked lime with ground slag, molding the mixture by hand or in a 

 brick-machine, and drying or steaming the product. The term "slag 

 blocks ", on the other hand, will be applied to the products made by 

 pouring molten slag into brick-shaped molds. 



Slag Bricks. 



The structural products included in this chapter under the head 

 of "slag bricks " include those which are made by mixing granulated 

 slag with slaked lime or with slag cement, molding the mixture in a 

 brick-press or by hand, and drying it in the air, with or without the 

 use of steam. It will be noted that all the raw materials used in this 

 industry are the same as those utilized in the manufacture of slag cement; 

 and indeed the manufacture of slag bricks may be considered as being 

 merely a specialized phase of the slag-cement industry. 



Though the slag-cement industry of the United States is in a fairly 

 satisfactory condition no serious attempt seems to have been made to 

 prepare slag bricks, tile, pipes, etc., on a commercial scale. Small amounts 

 of slag bricks have been made for use about the mills and furnaces 



* Over half of the material contained in this chapter is reprinted, by courtesy 

 of Engineering News, from an article by the present writer published in its issue 



of April 30, 1903. 



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