Patent GB-295338-A (GB)
Title: Improvements in or relating to processes and apparatus for the treatment of metallic ores or other metallic products
IPC: C21B13/08
Filed: 1927-02-10
Abstract: 295,338. Rowlands, T. Feb. 10, 1927. Rotary furnaces; cooling discharged materials. - In the reduction of ores &c. in a rotary furnace, the ores &c. are heated with solid carbon or partly devolatiled coal and reducing gases obtained from the low temperature carbonization of coal &c., the gases resulting therefrom being treated to convert the carbon dioxide or a large proportion thereof into carbon monoxide and the lowtemperature carbonization being effected by the sensible heat of the reduced ore and gases obtained at various stages in the process. The ore &c. is fed by a shoot 9 into a rotary preheating chamber 1, then into the rotary reduction chamber 2 where it is mixed with fuel and reduced with the aid of reducing gases and finally the reduced ore passes into the chamber 3 where it is cooled, the sensible heat being used for the low-temperature carbonization of fuel. The shoot 9, Fig. 2, is fitted into the non- rotating section 10 through which also the exit 12 for gases is built. An expansion joint with seal is formed between the wall 1<1> of the chamber 1 and the section 10 by a ring 13 which is. kept in contact with a ring 14 secured to the wall 1<1> and a ring 15 attached to the section 10, by springs 16 bearing against lugs 19 in the ring 13, and being carried by screws 17 secured to the ring 15. The chamber 2 is heated by the gaseous products from the chamber 3, these gases being led into longitudinal passages 20 formed in the walls of the chamber. These gases are also caused to pass through and over the mass of the charge in the chamber. The low-temperature carbonization chamber comprises a retort 23 which fits in the chamber 3 leaving an annular space into which passes the metal from the chamber 2 and surrounding the retort provides in the cooling of the said metal the necessary heat for the treatment of the fuel in the chamber 23 which is supported by arms, spiders or vanes 72. The cooled product leaves the chamber 3 by a passage 73 which leads to a passage 84 formed in a non-rotating section 83. The coal &c. is fed to the chamber 23 from a hopper 21 through a passage 24, Fig. 8, formed in a non-rotating end section 27 which also carries the gas exit 28. The joint between the rotating chamber 23 and the section 27 is made gas-tight by a ring 29 which engages the end of the retort 23 at 30 and the end face 31 of the section 27 being kept in position by springs 32 carried by screws 34 and contacting with lugs 33 engaging the ring 29 which may be provided with packing 36 adjusted by a covering 37. An alternative means of sealing the joint is also described. An expansion joint between the chamber 3 and the retort 23 comprises a ring 54 secured to the chamber 3 and which contacts with the end 46 of the retort 23. The ring 54 is provided with packing 55 which may be adjusted by a ring 56. A stirrer and scraper as well as a pipe for the introduction of gas such as steam may be fitted to the section 27, and gases as well as devolatiled fuel are withdrawn through openings 70, 71 which lead to openings in a non-rotating ring which are also connected to a conduit 63. The fuel &c. is conducted by this conduit to a conduit 77 and so to a duct 78 formed in a non-rotating section 79 and communicating with a duct or ducts formed in the chamber 2. The chambers 1, 2 and 3 may be formed as a single cylindrical or conical vessel which may be reduced in diameter at one or more parts or may be conical in shape : and the chamber 1 may be placed coaxially within the chamber 2. The gases from the retort 23 are passed through a gas-stripper 118 for recovery of the bye-products and may be passed into the chamber 2 near the end 85 so that they pass in opposite direction to the stream of ore. The gases may then pass into the preheater 1 which may also be heated by gases passing through passages in the lining. The gases withdrawn from the chamber 1 at 88, 89 are passed through a regenerator 90 and then are used in other parts of the apparatus. The chambers 1, 2 and 3 may be heated by burners supplied with gas, oil, coke &c. and oxygen with or without air. A portion of the gases leaving the chamber 1 may be used for preheating any of the raw materials or the air &c. used for heating the recuperator 90. Gas is introduced into the passage 20 of the chamber 2 from mains 91 by a passage 94 in a non-rotating section 93, said passage being in communication with ports 95 leading to the passage 20, in the chamber 2. Outlets are provided in the passage 20 so that gases may enter the chamber 2. In the treatment of iron ore, the process is conducted at a temperature of 500-950‹ C.