C—ls

8

S %- Per Cent. Silica .. .. .. ... .. 20-24 Titanic oxide .. .. .. .. 13-20 Alumina .. .. .. .. .. 8-63 Ferrous oxide . . . . .. .. 7-72 Oxide of manganese. . . . . . . . 0-97 Lime .. .. .. .. .. 32-40 Magnesia . . . . . . . . . . 16-42 Phosphoric anhydride .. .. .. 0-11 Heat 10. After the metal from heat 9 had been teemed the furnace was immediately charged again with a similar charge to that used in heat 9, except that the coke used was ground to pass an -J—in.-mesh sieve. The composition of the two charges was as follows: Ironsand, 6001b. ; coke-dust to pass £ in. mesh, 70 lb. ; coke-breeze, 40 lb. ; lime, 50 lb. The materials were again intimately mixed as in the previous heat. A second charge was put in after an hour's run. The reduction was completed and the slag tapped after 3 hours 36 minutes. For carburization 40 lb. of coke-dust was used, and. later 10 lb. carburite was added, and was complete in 1 hour 33 minutes, at which point 88 lb. of ferro-silicon was added, and the metal teemed after a total run of 5 hours 51 minutes.

Electrical Measurements. — Heat 10. Date: 26th August, 1921.

Total length of run .. .. .. .. . . . . 5 hr. 40 mm. Effective length of run .. .. .. .. .. 4 hr. 12 mm. Mean volts.. .. .. .. ... .. .. .. 144 Mean amps .. .. .. .. .. .. .. 2,315 Mean watts .. .. .. .. .. .. .. 311 Watts (= volts X amps) .. .. .. .. . . .. 323 X.V.A. (= watts X time) .. .. .. .. .. ..1,388 Total units (K.W.H.) consumed x t-25 .. .. .. .. 1,51.0 Pig iron produced . . . . . . .. .. .. (lb.) 831 Units (K.W.H.) per ton of pig .. .. .. .. ..4,151 Slag made .. .. . . .. . . .. .. (lb.) 836 .., . Slag 836 . ~ RatlO =—?■ = — 1-006. Iron 8!il Metallic iron charged in form of sands . . .. .. (lb.) 743 Metallic iron as ferro-silicon . . .. . . .. .. (lb.) 69 Lime, charged . . .. .. .. .. . . (lb.) 110 Coke and breeze charged .». .. ... . . .. (lb.) 260 Lime per ton of iron produced .. .. .. .. (lb.) 297 Coke-breeze per ton of iron produced .. .. .. .. (lb.) 702 Yield of pig iron per cent, of iron charged . . . . . . .. 10234

Units. Time. Volts. Amps. Watts. Remarks. No. 1. No. 2. I 5-49 5-52 6-00 6-15 6-30 6-45 6-50 7-15 7-30 7-45 8-00 8-15 8-30 150 158 154 175 2.500 2,500 2.350 2.250 360 370 370 372 491,055 504,232 First charge. Full tap. 160 160 170 164 170 175 2,500 2.500 2,500 2,400 2,600 2,250 373 370 375 376 377 367 494,216 504,400 Second charge. Off for 17 minutes. 9-00 9-15 160 104 2,500 2,000 380 210 494,580 501,781 Off for 4 minutes ; slag overflowing. Off for 7 minutes ; slag overflowing. Off 25 minutes for additions and slagging. Off for 15 minutes. Off for 9 minutes. Off for 5 minutes. Off for 6 minutes. 9-50 10-19 10-37 11-00 11-15 11-32 120 109 100 110 109 Off 2.800 1,900 2,250 1,650 1,900 230 190 210 185 180 494,657 504,862 Run terminated.