Patent GB-571240-A (GB)
Title: Process for producing metals
IPC: C21B13/14
Filed: 1942-02-05
Abstract: 571,240. Extracting metals; extracting iron ; treating ores. MINERALS & METALS CORPORATION. Feb. 5, 1942, No. 1540. Convention. date, April 9. 1941. [Classes 72 and 82 (i)] In the production of a metal from its ore, the latter is made into a bed through which an oxidizing gas is passed to roast the ore, an alkali, such as soda ash, is then charged on to the top of the bed of roasted ore and then, while the bed retains the heat of the roasting step, a reducing gas is passed through to reduce the ore. The reduced metal may be compacted while hot and preferably in a reducing atmosphere and the compacted metal may be melted under non-reduoing conditions to slag off the gangue content of the ores. The ore may be bedded in a series of layers, each of a uniform size of particles, the layers of finer particles being placed at the-top and those of coarser particles at the bottom of the bed, and finely-divided carbonaceous fuel may be added to the ore for either or both the roasting and reducing operations. The pan 11 with a perforated, slotted or permeable hearth carried by rollers 12 on a track 13 is moved under one of.the hoppers 56, where it is filled with raw material which may be mixtures of several kinds of ores, the mixtures being combined uniformly or stratified. The material in the pan is then levelled by a bar 63 and the pan moved into position between the hoods 28, 44 which are raised and lowered respectively to make gas-tight contact with the pan. A blower, not shown, is then operated to provide a downdraught through the hood 28 and the blower 51. may also be operated to drive air with or without hot gases down through the hood 44. Combustion gas is introduced through the pipe 45 by opening the valve 46, and the, burners 48 are lit. If fuel such as 3 per cent of carbon is added to the ores, the combustion gases may be turned off as soon as the combustion of the fuel is started and then air alone is used. The ore is thus roasted to get rid of moisture and volatile matters and the pan 11 may be vibrated by the eccentric 14 during this treatment to increase the contact between the solids and the gases. When the roasting has .been completed, the flow of gases is stopped by closing the valve 50 and an alkali, such as soda ash, is added to the ores. Reducing gas is now supplied to the hood 44 through the passage 43 and is drawn through the roasted material by suction blowers and the pan may again be vibrated. As soon as the reduction is complete, the pan 11 is, moved to a position upon the section 18 of the track, the cover 24 removed from a hopper 20 and the hot material is dumped into the hopper where it is compacted while still being heated by hot reducing or neutral gases introduced through a passage 22 by rolls 25, 26. After the pan 11 has been dealt with, the pan 11A is moved under the hopper 57, filled with material and then moved between the hoods 28, 44, the process being carried out as described in connection with the use of the pan 11. After the reduction is complete, the pan 11A is moved to the left and its contents dumped into the hopper 19 where it is compacted by rollers 25, 26. The compacted metal may then be melted under non-reducing conditions to slag off the gangue. The treatment of ores of iron, copper, zinc, lead and tin is referred to.