GB190928755A - An Improved Method of and Means for Recovering Gases Rich in Sulphur Dioxide Separately from Gases Poor therein, in Roasting and Oxidising Processes. - Google Patents

Abstract

28,755. Schlippenbach, Baron F. von. May 24, [Convention date]. Roasting-furnaces ; charging. - Relates to mechanical furnaces for roasting ores in which the composition of the sulphur dioxide gases evolved at any particular part of the furnace varies from time to time, and consists in recovering separately the rich and poor gases by leading them to separate collecting-chambers, the rich gases being afterwards conveyed away for use in the manufacture of sulphuric acid, and the poor gases being led to the stack. In the form of apparatus shown in Figs. 1 and 2, the ore is fed from a hopper b on to an annular rotating grate a. The ore is ignited in any suitable manner and air is forced down through the ignited mass. The space beneath the grate is enclosed and divided by partitions d into compartments e, each of which communicates by means of conduits f, g with gascollecting chambers h, i respectively. The upper part of each chamber h, i is in the form of a bell dipping into tanks p, filled with water, sand, glycerine, or the like, the bell being annular and the bell m cylindrical. The bells are also provided with outlets n, o. The bottoms j, k of the chambers h, i are connected to the tanks p, q and supported by the conduits f, g which rotate with the grate a. If desired, the bottoms j, k may be provided with flanges dipping into the tanks p, q, which in this case may be stationary. Within each of the bells is fastened a closing plate r, s adapted to close a certain number of the gas conduits, so that, during the rotation of the grate, the conduits f, leading from the compartments e beneath the freshly-charged portion of the grate, will be open, while the remaining conduits f will be closed. Also the conduits g leading from the parts of the grate containing desulphurized ore will be open, and those leading from the freshly - charged portions of the grate will be closed. In a modification, the grate is fixed, and the hopper band bells l, m with the closing plates r, s rotate. Figs. 5 and 6 show the invention applied to a furnace with a rectilinear grate. Each of the compartments e' beneath the grate a<2> is connected to the collecting-chambers h<2>, i<2>, which may be arranged as shown or concentrically. The rotation of the bell l<2>, m<2> may be effected by providing each of them with a toothed wheel v engaging with a rack w upon a carriage x which supports the feeding-device b<2>. Rotation of the bells also causes the rotation of the closing-devices r<2>, s<2> above the open ends of the conduits f<2> g<2>. In this arrangement, feeding of the ore and rotation of the bells take place only during the movement of the feeding-device in one direction. In place of the closing-plates described above, other devices such as cocks, valves, dampers, or the like adapted to be operated by hand or automatically may be arranged in the pipes conducting the gases to the collecting-chambers. A motor may be made use of for actuating the closing-devices. Also instead of rotary bells being used in the arrangement shown in Figs. 5 and 6, rectilinear reciprocating bells may be used. Fig. 7 shows a box-like slide y adapted to cover a certain number of the conduit orifices and rotating with and attached to the bell. An outlet pipe n<3> allows the escape of gases. A plate r<3> connected with the slide serves to open and close the conduits f<3> leading from the empty part of the grate. Gases flowing through the uncovered orifices of the conduits enter the chamber i' and are draw off separately. If desired, three or more different currents of gas may be drawn off separately by increasing the number of collecting- chambers accordingly.