Harbison-walker Refractories Company

A Study of the Blast Furnace Harbison-walker Refractories Company

This historic book may have numerous typos, missing text or index. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1911. Not illustrated. Excerpt: ... 1*1 ATE RIALS -ORES CHAPTER II T is difficult to frame a definition which shall be absolutely accurate from all points of view, and furthermore, usage has much to do with the various terms employed, but in general iron ore is a compound of iron combined with certain elements. This compound is more or less intimately mixed with earthy impurities or gangue as it is called. In order to be an ore in the sense here used, the iron must be in sufficient quantities and in combination with such elements as shall permit its smelting on a commercially profitable basis. Although iron is one of the most widely distributed of the elements, it practically never occurs native or in the form of pure metallic iron, so great is its affinity for other elements. In general, the compounds of iron available for the blast furnace are the oxides, which include the three groups, the Hematites, the Brown Ores, and the Magnetites, these comprising more than 99% of the ore produced in this country, and the Carbonates, less than 1%. The above are given in the order of their importance. There is also the general division of all ores into two classes, i.e., Bessemer and nonBessemer or basic, dependent upon the content of phosphorus. This terminology comes from the fact that in the acid Bessemer method of making steel, no phosphorus is removed during the process. Hence, the pig iron from which the steel is made must have no greater quantity of phosphorus than will maintain the Bessemer limit, .1% phosphorus in the steel. Practically all the phosphorus in the ore goes into the pig iron. This usually means that a Bessemer ore must contain no more than .045% to .05% phosphorus, the limit being .001% phosphorusfor each per cent. of iron in the ore. Bessemer and non-Bessemer ores are in turn separat...