US1892114A - Smelting zinc and the like - Google Patents

Description

Dec. 27, 1932. w. A. OGG

SMELTING' ZINC AND THE LIKE Filed Jan. 15, 1931 4 Sheets-Sheet 1 Dec. 27, 1932. w. A. OGG 1,892,114

SMELTING ZINC AND THE LIKE Filed Jan. 15, 1951 4 Sheets-Sheet 2 Wtru'm HEEL-Imp 010 g 819M307 72? 7 fli ys Dec. 27, 1932. w OGG 1,892,114

SMELTING ZINC AND THE LIKE Filed Jan. 15,1951 4 Sheets-Sheet s c cz, 0M?

Dec. 27, 1932. w. A. OGG 1,892,114

SMELTING ZINC AND THE LIKE Filed Jan. 15, 1931 4 Sheets-Sheet 4 Invenior: Wm d; 0 19/43 M Z Patented Dec. 21, 1932 WILLIAM A. OGG, OF NEWTON, MASSACHUSETTS SME'LTING ZINC AND THE LIKE Applicationfiled January 15, 1981. Serial No. 508,326.

This invention relates to the smelting of zinc and like vdlatilizable metals, and the object is to provide a novel method for sepa rating such metals from their compounds by 5 gaseous reduction under favorable thermal conditions with resultant advantages which will appear to those skilled in the art as the description proceeds.

The method may be well understood by the description of the operation of the one form of furnace suitable for practising the'same shown by way of example in the accompanying drawings, wherein:

*ig. 1 is a transverse section through the 1 furnace; f

Fig. 2 is a side elevation with parts broken away of one end of the same;

Fig. 2a is asimilar view of the other end of the furnace; and Fig. 3 is a plan of the parts appearing in Fig. 2. v

eferring to Fig. 1, the furnace there shown takes the general form of a tunnel having the side walls 5 and 7 and the roof 9 divided horizontally into a. flame chamber 11 and a reaction chamber 13 by a heat radiating wall, herein shown asan arch 15 of suitable material having a high heat-conducting capacity, convenientl bricks of silicon carbide (carborundum). it one end, which may be termed the intake end (see Fig. 2), an end wall 17 closes the flame chamber while the reaction chamber beneath ma be closed by a suitable movable door 19. t the other end,

which may be termed the output end (see Fig. 2a), the flame chamber is closed by the end wall 21 and the reaction chamber may be partially closed by an end wall 23, there being, however, an ofltake opening 25 which may be closed by a suitable door, not appearing as such in the figure but the position of which is indicated by the showing of the hoisting mechanism 27. v

Gases may be burned in the combustion chamber 11 to heat the arch 15 so that it will 7 radiate heat upon reaction material in the chamber 13 below. I have herein shownmains 29 for fuel gas from which pipes 31 discharge into the flame chamber through ports 33 while air for combustion is supplied through mains 35through the passages 37 to ports 39, the products of com ustion being disposed of in any suitable manner, not illustrated in the drawings.

Crude zinc oxide in the form of a fairly thick porous layer of finely divided particles, conveniently roasted and sintered zinc ore, may be supported in the reaction chamber 13 on a foraminous grate 41 which may be similar in construction to the well known grate utilized in the Wetherill process for the manufacture of zinc oxide, this grate being of a length corresponding to the length of the reaction chamber 13 and movable in and out from the same through the doorway of door 19, being herein shown as mounted on trucks 43 running on rails 45. Referring to Fig. 2, the grate may be withdrawn to the left in the figure and on being returned toward the right the plow 47 may be suitably lowered by means of the adjusting mechanism 49 to scrape off any residues remaining upon the grate into bin 50, and the grate thus cleared passes beneath suitable hoppers 51 t and 53 having the feeding devices 55 and 57 respectively, herein illustrated as drivenby electric motors 59 and 61, from which hoppers material is deposited upon the grate, the charge being levelled off by the levelling bars 63 and 65, any surplus being discharged to so bins 64 and 66. I have herein shown two hoppers as it maybe desirable to deposit first upon the grate from hopper 51 a layer of inert material, such as crushed gan e, to serve as a bed to receive the crude oxi c, this bed further serving to facilitate the'distribution through the mass of oxide of the gas supplied through the grate as presently to be described and as such being analogous to the similar bed described in the patent to ,Wemple 1,591,253, July 6, 1926. When the grate thus loaded is pushed into the furnace, the door 19 is closed and the reaction may f begin.

In accordance with my invention I utilize for smelting the zinc a hydrocarbon gas (paraflin gas) preferably in the form of socalled natural gas. For simplicit we may consider natural gas to consist o methane .as it does in large part. The higher hydrocarbon gases of the same series will act similarly although the reaction will be specifically difierent. The theoretical reaction is expressed by the equation Zn0+CH =Zn+ CO+2H Herein natural gas is supplied from main 67 through pipes 69 and discharged to the reaction chamber beneath the grate 41 and it penetrates through the openings of the grate and through the porous charge of crude zinc oxide. When the gas reaches the surface of this layer, it will encounter ore heated by radiation from the arch 15 to a temperature favorable for reaction. As the reaction proceeds the upper surface of the layer wastes away, the products being gaseous or vaporous, and fresh surfaces are exposed to the radiant heat without the accumulation of substantial amounts of residue since no solid reduction fuel is present and the only solid residuum is the gangue which may be present. There is thus practically no obstruction to the transmission of heat by radiation from the arch 15 to the ore and a very high thermal efficiency is attained.

The zinc vapor and the gaseous products of the reaction pass lengthwise of the furnace and are withdrawn through the port 25 (see Fig. 2a). As the arch 15 toward which the zinc vapors rise is heated, they are maintained in a vaporous form until withdrawn from the chamber.

Externally of the furnace the metal vapors are separated from the gases, which latter are of a combustible nature and which will .recover a considerable portion of the heat units of the natural gas originally used. As the volume of these gases is large, ll prefer to separate the metal values by chilling the efduent from the furnace suddenly, thus .causing the zinc to pass directly into solid form as blue powder for collection for further treatment in any manner well known to the art. I have herein illustrated the gases as assing into a large, thin-walled chamber 71 in which they are suddenly cooled. Any blue powder separating may fall by gravity to bin 73. Chamber 71forms an intake to v a cyclone 74, not completely shown but of a construction well known, in which the gases :are given-a whirling motion, and on account of the great weight of the blue powder the greater portion thereof is thrown out by the centrifugal action and falls to collecting bin 75. From the cyclone the remaining gases pass through downtake 77 to chamber 79 which contains a conveyor 81 to collect and carry away any solid materials deposited therein and finally pass to a bagging unit 83 where any remaining solid material is separated from the gases which are led thence for utilization in any desired manner, whether for combustion in flame chamber 11 to provide heat for heating arch 15 or other I am aware that the invention may be em to the foregoing description to indicate the scope of the invention.

I claim:

1. The method of recovering metal values from crude oxides of vaporizable metals characterized by spreading the crude oxide on'a foraminous support and exposing it beneath an externally heated wall while passing a reducing gas up through the support.

2. The method of recovering metal values from crude oxides of vaporizable metals characterized by spreading the crude oxide in an extended layer and exposing the layer in opposition to an externally heated wall to be heated by radiation therefrom, supplying a reducing gas to the heated oxide and withdrawing the evolved vapors from the clearance space between the oxide and wall.

3. The method of recovering metal values from crude oxides of vaporizable metals characterized by spreading the crude oxide on a for aminous support and exposing it beneath an externally heated wall while passing hydrocarbon gas ,up through the support.

4. The method of recovering metal values from crude oxides of vaporizable metals characterized by spreading the crude oxide in an extended layer, passing a reducing gas up through said layer while exposing the up- WILLIAM A. OGG.

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