MAKING PIG IRON AND STEEL.

Taranaki Daily News, 21 January 1922, Page 11

MAKING PIG IRON AND STEEL.

. FROM PACIFIC COAST BLACK SANDS. (By James L. Avis jr. in the Iron Trade Review.) During the past 20 years much interest has been centered upon the problem of utilising the black iron oxide sands which line the Pacific coast from Alaska to southern California. The investigations of the United States geological survey have indicated that this sand is present in great quantities and that it contains more than 50 per cent, iron. Metallurgists have made numerous attempts to smelt the ote, but thus far their efforts have not been carried successfully beyond the experimental stage. One of the most promising series of investigations on the reduction of the black sand ore is that recently completed at Sedro Woolley, Wash., by the New Era Iron and Steel Corp. Tests conducted in a miniature blast furnace have been so successful that the company has perfected a manufacturing organisation and has announced that it will start to make iron and steel on a commercial basis in the near future. ORE IS BRIQUETTED. The process of smelting the iron bearing sands, which was developed by William Tyrrell, consists of briquetting the ore with the aid of a natural binder and melting the briquettes in an ordinary blast fu’.nace, the chaige being approximately 47 per cent, fuel, 47 per cent, briquettes, and 5 par cent. flux. In preparing the briquettes the biack sand first is put over a jig, almost no effort being made to concentrate it. After passing from the jig, the sand is mixed with definite proportions of lye, diatomaceous earth, sodium sulphate and other materials. In experimental practice th£ mixing was accomplished by men with hoes and shovels, much the same as mortar is v mixed. The binder mentioned above is not only a powerful cohesive agent, but acts also as a purifier or scavenger. After the various ingredients becqme thoroughly intermingled, the mixture is molded in long troughs about 6 inches wide and 3 inches deep, marked off in squares, transferrad to a dryer, and later charged in the blast furnace. The strength increases as the temperature rises and does not start to decrease until closely approaching the fusion point. Standard practice is followed in operating the blast furnace, the briquetted ore, coke and limestone being charged in proportions of 47, 47 and. 5 per cent., respectively. Thus far no trouble has been experienced in building up the hearth, as was the case in earlier attempts to smelt titaniferous ores. This is explained by the fact that the titanium and chromium ore are eliminated by the binder. MAKE ELECTRIC FURNACE STEEL. In investigating the properties of the black sand pig iron, a number of heats were made in the electric furnace, using varying percentages of the iron. Steel castings were produced from a mixture of about 39 per cent, open-hearth scrap, 44 per cent, foundry scrap and 16 per cent, black sand pig iron. The castings were clean, homogeneous, ana machined satisfactorily when annealed. The carbon content was 0.2 S per cent, and the tensile strength averaged 69,000 pounds pel* square inch. Another melt was made containing 50 per cent, black sand pig iron. The steel was poured into a small ingot about 4 inches in diameter and 30 inches long, and forged to 1} inches square. The metal was fairly resilient at high forging temperatures. The bar later was formed into a sharper tool and after hardening ,and tempering, gave satisfactory service. (The tensile strength was 120,000 pounds ’per square inch and the carbon content 0.69 per cent.