Unless you're making steel it will join asbestos and lead paint in the annals of industrial history.
Chuboy coal can safely stay in the ground. It's not needed to make steel.
Properties of Iron Made by the Process of Hydrogen Reduction
- Heihachi Kamura, M.S.b
+ Author Affiliations
- b Professor, Metallurgical Dept., Meiji College of Technology, Fukuoka‐Ken, Japan.
Abstract
It is well known that iron oxides and oxide iron ores are easily reducible by hydrogen at a comparatively low temperature. In the research herewith reported upon, the reduction of a wide variety of iron ores was carried out on laboratory scale starting with ore samples weighing 2 to 5 kg. The chemical and physical properties of the iron produced were carefully studied. The ingot iron obtained by melting the sponge was forged and analyzed. Tensile and impact tests are recorded. The resistivity was determined on test pieces made of forged materials. The products from various iron ores are compared. This research also confirmed previous observations that some of the phosphorus present as oxide in the iron sponge is removed by the slag during melting as shown by analyses of iron and slag. The ease of reducibility by hydrogen varied for different ores. The more compact the ore, the more difficult the reduction. Easily reducible ores such as those of Johole and Taihei were nearly completely converted to the metallic state at 900° to 950° C. in 3 to 4 hr. Magnetite sands were most difficult to reduce, requiring temperatures above 1,100° or 1,150° C. When melting the product in a crucible no difficulty was encountered when more than 95 per cent of the iron in the sponge iron was in the metallic state. No chemical reaction occurs which would bring about evolution of gas as is the case in the melting of ordinary iron and steel containing carbon. The melting progresses very quietly and a sound ingot free from blow holes is obtained. Ores containing phosphorus and sulfur below 0.03 and 0.07 per cent respectively, gave iron which had less than 0.02 per cent of these two elements combined. If we start with an ore low in P, S, Mn, etc., it is not difficult to keep the total amount of impurities in the melted iron under 0.1 per cent. The physical properties of hydrogen reduced melted iron depend upon the impurities present but when these are low the elastic limit and tensile strength are about the same as those for electrolytic iron, Armco iron or highest grade Swedish iron. On the other hand hydrogen reduced iron has a higher per cent elongation. The impact test values are much higher than those for high grade electrolytic iron or Armco iron. Phosphorus in the hydrogen reduced iron increases the elastic limit and the tensile strength and decreases the elongation. On the other hand the impact value is diminished appreciably by an increase in phosphorus content. The impact value varies not only with the amount of residual impurities in the iron after hydrogen reduction but with the kind of ore used. An exact explanation for the latter is lacking. The subject requires further study. The hardness of the iron by hydrogen containing but a small percentage of impurities is about 70 Brinell. The oxides of phosphorus are more difficult to reduce than the oxides of iron. At any constant temperature the percentage reduction of phosphorus is much lower than that of iron as is demonstrated in the case of the reduction of Taihei and Johole ores at temperatures ranging between 600° C. and 1,150° C. At 600° C., the percentage of reduction for iron is between 50 and 60 and for phosphorus is less than 30. At 900° C., the percentage for iron is 90 to 95; and for phosphorus 60 to 70.