OCR Text |
Show EXPERTS OF UTAH FACE NEW PROBLEM The fame of Utah as an ore smelting smelt-ing center is acknowledged the world over .mil there is in use within this state aa modern a smelting pracHce as (here Is anywhere. The smelting experts of Utah have been called upon up-on to sohe some intricate Bmelting problems in the past, and there now exists another difficulty which must l-c surmounted arising out of the new sintering practice in ogue In several plants. The following editorial in Metallurgical and Chemical Engineering Engineer-ing Journal of New York explains ibis difficulty: The occurrence of two disasters by the explosion and fire at Utah lead smelting plants has directed attention atten-tion to a contingency which apparently appar-ently did not exist prior to the use of the latest method of sintering fine ore. At the Tooele Bmelter of the International Smelting A Refining company an explosion 01 flue duel caused serious damage to the roaster roast-er flue, and at the Mid vale plant of the Uuited States Smeltlnc company 8 spon'aneuiis fire destroyed a large I number of baga. Both disasters involved material loss and were quite extraordinary. 4n the case of the flue-dust explosion the usual provision of c-xplosion-door? was insufficient t prevent wrecking the flue, while the destruction In the bag-house fire was of much greater magnitude than that caimed by In-1 clplent fires which sometimes occur in such plants. In each case the trouble is ascribed as-cribed to the presence of finely divided di-vided elemental sulphur in rhe gases from the sinter-roasterp This male-rial, male-rial, settling In the flue-dust and bng accretions, apparently gives use to dust explosions when the conditions of temperature) and oxidation are favorable, fa-vorable, .similar to the progressive explosions ex-plosions of other finely divided combustibles com-bustibles such as coal dust. That similar explosions have not occurred before probably is due to the fact that In earlier forms 01 roasters the sulphur was eliminated as some form I of oxide instead of a sublimed ele-ment, ele-ment, the latter apparently resulting 1 from the present method of roasting Roth the plants mentioned mplov the Dwight & Llovd method of sinter-roasting a characteristic feature .r which is that a comparatively tbiu laver of ore Is quickly agglomerated; Into a porous mass, highly suitable for smelting This mixture Is exposed expos-ed to heat for only a short tlm. and I the quantltv of air available lor oxidation oxi-dation Is limited,1" tn.Bt which can be drawn through the charge during Its passage over the wIihI-i.o,, Under such conditions It is ike)v that more sulphur would he sublimed and les oxidized, than in the oW forms of hearth roasting furnace, or! In other forms of asnlomeratlnK fur-J herleln pot system of sinter-roasting, I the charge is deeper, the sir supply more copious, and the progress Ive sintering slower than in the Dw ight M- Lloyd method. There is a greater! probability of sulphur being elimin ated as oxide It appears, however, that even with the Dwight ft Lloyd svstem the tendency ten-dency to distill sulphur into the flue j gases varies with the physical con-! dition of the roaster charge. audi the likelihood of resulting explosions also is modified by these conditions. It has been observed thai a very wet charge results in the distillation of more sulphur than comes from a rr-a Bonably dry mixture Some moisture Is desirable in the mixture, in order to handle it properly, nn,j indeed it is customary to add some water nt itlmes; but such excessive moisture as occurs In frozen ore apparent!; is detrimental. The problem If being investigated, and probably will be well in hand be fore other disasters can occur. The suggestion has been made that the tendency to distill sulphur might be turned to advantage by creating conditions con-ditions most favorable for this action, ac-tion, and recovering the sulphur thus f-.rmed. This would have a distinct bearing on the smelter fume question At present, means are being adopted to cool the ases in the flues and fur ther to regulate automatically the temperature of the ases cnterinc ib bag bouse by admitting a variable quantity of air with them. |