C—ls

10

Total length of run .. .. .. .. .. .. 8 hr. 7 mm. Effective length of run . . . . . . . . . 6 hr. 12 mm. Mean volts .. .. . . .. .. .. .. 147 Mean amps .. .. .. .. .. .. .. 2,235 Mean watts . . .. . . . . .. . . . . 331 Watts (= volts Xam [is) .. .. .. . . .. .. '328 X.V.A. (= watts x time) .. .. .. .. .. .. 2,050 Total units (K.W.H.) consumed x 1-25 .. .. .. ~2,245 Pig iron produced . . . . . . . . . . .. (lb.) 984 Units (K.W.H.) per ton of pig .. .. .. .. -.. 5.111 Slag made .. .. .. .. .. (lb.) 1.666 Ratio =S = 1-693. Iron 984 Metallic iron charged as sands .. .. .. . . (lb.) 996 Metallic iron charged as ferro-silicon .. . . .. . . (lb.) 79 Lime charged of iron produced .. . . ... . . (lb.) 150 Coke and breeze, charged .. .. . . . . . . (lb.) 382 Lime per ton .. .. .. .. .. .. lib.) 341 Coke per ton of iron produced .. .. .. .. (lb.) 825 Yield of pig iron per cent, of iron charged .. . . .. . . 91-53 The analyses of the products obtained were as follows : — Pig Iron (before addition of Ferro-silicon.) Per Cent. Carbon by combustion .. .. .. 3-538 Silicon .. .. . . .. .. 0-068 Sulphur .. .. .. .. .. 0-012 Pig Iron (as Cast). Graphitic carbon .. .. .. .. 2-490 L ,-, , „„, „ Combined carbon 0 . 529 j Total carbon 3-019. Silicon .. .. .. .. .. 2-055 Sulphur . . .. .. . . . . 0-006 Phosphorus . . . . . . . . 0-329 Manganese .. . . .. . . . . 0-237 Titanium .. .. .. .. . . 0-051 Slag. Silica .. .. .. .. . , 18-64 Titanic oxide .. .. . . .. 9-95 Alumina .. .. .. .. .. 7-24 Ferrous oxide .. .. .. . . 5-50 Oxide of manganese .. . . . . 1-18 Lime .. .. .. .. .. 31-74 Magnesia .. .. .. .. .. 24-85 Phosphoric anhydride .. .. ..0-11 The average yield, taking all three pig-iron heats together, was 91-64 per cent., and the consumption of lime 347 lb., coke 812 lb., and ferro-silicon 237 lb. per ton of iron produced. The average current-consumption was 1,949 K.W.H. per ton of iron produced. Heat 12. After heat No. 11 was completed the lining of the furnace was examined and it was found that the slag had worked through between the magnesia brickwork and the basic material forming the hearth, and also a large portion of the hearth had been eroded away. However, the bad places were patched, and it was decided to run one more heat and to make steel direct. The same charge as before was put in, as follows : Ironsands, 600 lb. ; coke-dust, 70 lb. ; coke-breeze, 40 lb. ; lime, 501b. The second portion was charged into the furnace after 1| hours' run, and. the reduction was complete after 4 hours 39 minutes ; the first slag was then poured. 56 lb. haematite ore and 501b. lime were then added, and later 91b. fluorspar, 281b. haematite ore, and the second slag poured an hour after the first. There were then further additions of 23 lb. lime, 98 lb. haematite ore, and the final slag poured off an hour later. The metal was then carburized with coke-dust and 14 lb. ferro-silicon, 3 lb. ferro-manganese, and a souU piece of aluminium added, and the steel poured into ingots after a total run of 8 hours 32 minutes.