US1243798A - Furnace for smelting ores. - Google Patents

Description

C. J. BEAVER & E. A.'CLAREMONT.

FURNACE FOR SMEETING ORES. VAYPLICATION' HLED APR. n. 1916.

3 SHEER-SHEET 1.

LMSEQS, Patented M. 23, 19-17.

C. J. BEAVER & E. A. CLAREMONT.

FURNACE FOR SMELTING QRES.

APPLICATION FILED APR. 11. 1916.

' LMBJWQQ Patented Oct. 23,1917;

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APPLICATION FILED APR. 17' 1916- I 1,243,798. i Patented Oct. 23, 1917.

3 SHEETS-SHEET a.

. p' NraEn sraa ns 'EEATEET oEEic cnAaLEs JAMEs BEAVER AND ERNEST ALEXANDER, cLAEEMoNT, 0E cHEsHIaE,

ENGLAND. r

EIiRNAGE Eon si/iELTING oEEs.

Specification of Letters Patent. 0

Application filed April 17, 1916, Seria1No.9 1,760

T0 aZlw/wm it may concern:

Be it known that We, CHARLES JAMES BEAVER, and ERNEST ALEXANDER GLAREMONT, bothsubjects of the King of England, residing at Cheshire, in England, have invented certainnew and useful Improvements in Furnaces for Smelting Ores, of which the following is a specification; I

This invention comprises an improved furnace for smelting ores particularly rich lead ores but not suitable for all ores.

In the reverberatory furnaces for smelting rich lead ores now invogue, the heat and products of combustion are conducted into and through a horizontal chamber, 011 the floor of which the ore is placed, and thence to the chimney shaft. The chamber 'is provided with ports or doors by which air can at will be admitted into the chamber. The ore is heated up to a temperaturebetween 500 C. and 600 or thereabouts in an oxidizing atmosphere produced by the introduction of air and when suflicient time has elapsed for the sulfur and other impurities to be oxidized and gasified and taken off, the air inlets are closed and the heat increased'up to or about 1000 C. in a nonoxidizing atmosphere produced by the productsof combustion and of the smelting reaction ffilling the chamber.

During both processesthe ore is rabbled by hand through doors or other openings in the chamber.

In such a furnace difficulty is experienced in controlling the temperatures required and there follows an uncertainty in results. It is generally necessary to treat the resulting slag a second time to extract all the lead, a large percentage of which after the first treating remains trapped or bound in the slag and a sensible loss of lead takes place in the form of volatilized lead or lead compound which escapes by the chinmey shaft.

The object of our invention is to enable the smelting of such ores to be carried'on continuously as one. operation the ore passing from one temperature and one atmosphere to the other temperature and other atmosphere in a continuous passage through the furnace to have the temperature and atmosphere under better control and to avoid the loss in time, labor and material attendant on the present method.

We construct a furnace containing a long chamber preferably arranged horizontally,

Patented Oct, 23, 1917..

heated externally we out the products of combustion passing through the chamber) as by gases of combustion from a furnace which enables the end of the chamber into which the ore is introduced or fed; (hereinafter calledthe I front part) to be heated to and maintained ata temperature ;of from 600 C. to 650 C. while the other or farther end thereinafter called the farther part) c'an be heated toand maintained ata temperature'of or' above 900 C. as may be necessary for correct treatment of theore charge andprovided with means and ,mechanism herein after described. The front part of the chamber isprovided with means for introducing air and with means for extracting and carrying away'air gaseous fumes and products said means being so arranged that the air introduced after performing its functions is extracted Without traversing the farther part ofthe chamber. For example we may arrange a pipe orpipes across the center of the chamber, with holes toward the front part of the chamber and other openings in the Walls of the front part through which air can be injected or drawn and at the end of the front part an outlet furnished .with a fan or other form of suction device. The interior of the chamber is furnished with means such as automatic rabbles or rakes for turning and shifting the ore and slowly moving it along the chamber from the front part to' the farther part and assisting in the separation of the lead from the slag. The front part is provided with an inlet opening which may take the form of a hopper through which the ore to be treated is introduced or fed. Thefarther part is provided with means such as the sloping of parts ofthe hearth or floor and catch pits or wells to collect the molten lead and slag and to part of the chamber between the front part and the farther part of the chamberto assist in preventing air and gases in the front part from passing to the farther part.

In the accompanying drawings is shown an example of a furnaceconstructed in accordance with our invention,

Figure 1 represents an end elevation of the back end of the furnace.

Fig. 2 is a side elevation of the furnace.

Fig. 3 is a cross section on line AA of Figs. 2 and 6.

Fig. 4: is a longitudinal section on line B, B of Figs. 1, 3 and 5.

Fig. 5 is a cross section on line C, G of Figs. 2, l and 6.

Fig. 6 is a sectional plan in the line Fig. 9 paratus and Fig. 10 a longitudinal section on line G, G of Fig. 7.

Figs; 1, 2, 3, 4, 5 and 6 show the construc tion of a suitable type of furnace in which the fines and dampers are arranged so that the required variation of temperature may be attained in the interior of the furnace.

a is the combustion chamber, 6 is a longitudinal flue passing laterally of the chamber 25 at the same side as the fire connecting with flues 6 across the roof of the chamber all of which connect with a longitudinal flue b on the opposite side of the chamber and are severally controlled by dampers c the flue 6 leading into the vertical flue b which via the fines 6* and Z9 under the hearth leads to the chimney Z). Z is the externally heated chamber in which the smelting is effected the walls and roof of which are preferably made of suitable refractory material and the hearth i lined with material such as plumbago or the slag. resulting from the complete smelting of lead ore. e are air ports or inlets and e is a suitably perforated or slotted pipe fixed transversely across the chamber d, all provided with valves (not shown) to enable air in such quantities as desired to be introduced into the chamber. f is a tightly fitting door at the back end of the furnace for cleaning, repair, observation and emergency manipulation or corrective purposes. 9 is an out let pipe preferably furnished with a fan or other form of suction device 9 by which air is drawn in through the inlets e or 6 and which outlet pipe 9 may have a branch 9 to the back part of the chamber to bypass gaseous products, formed therein and maylead to scrubbers, towers or the like for treating and utilizing waste or by-products. 72, is a hopper for introducing the charge which when not in use is inclosed and is ap proximately airtight. as is a division wall constructed in the upper part of the chamber (Z above the pipe 6 as shown in Figs. 3 and 4. This wall may be so constructed as to contain ports m regulated by dampers x in place of the pipe 6 The object of this wall is to facilitate the maintenance of different atmospheric conditions at the front part and farther end of the chamber d. The hearth i is suitably shaped to avoid lodgment of parts of the charge as shown for instance at j at the front end of the furnace where the change enters and along the sides as at j. A part t of the hearth is raised above the general level tothe height of the slope y' This part 25 has a flat horizontal surface in the same plane as a height of said slope y' and has a curve or undulating forward face forming a vertical wall 6 which consists in directing the charge to the sloping surface j hereinafter mentioned. The rear edge of said part t means the inclined vertical edge of the slope 9' as shown in Fig. 3. The part of the hearth toward the rear end of the chamber past the lines o and v in Fig. 6 is gradually sloped away longitudinally and transversely or obliquely as at 7' and 7' respectively. toward one corner which constitutes the lead well Z to receive the separated lead, while in the opposite corner a pit 7c is formed to receive the separated slag drawn up the slope j by the rabbles or rakes hereinafter described.

Figs. 7, 8 and 10 are generally similar to Figs. 3, 6 and a respectively but show suitable mechanical rabbling or raking apparatus for the manipulation of the charge. Many known forms of mechanical raking apparatus could be used'but we illustrate two forms which we prefer as being most suitable to the physical state of the charge,

0 are rakes or rabbles consisting of arms or blades mounted on rotatable shafts. The arms or blades maybe in the form of sections of screw threads of suitable size for the degree and character of movement required in the various parts of the chamber. For instance at the front end of the chamber where the charge is introduced, the arms 0 preferably form small sections of screw threads acting as fingers or pickers, because the charge is 1n a powdery condition while passmg through the front end ofthe chamber, but at a later stage when the charge is r in a semi-plastic condition in the smelting Zone, the arms 0 preferably form large screw sections, while toward the end of the furnace on the slope of the hearth above referred to, complete or almost complete screws may be used in order to pass the charge laterally on to the slope j In Fig. 8 the positions of some of the rabble shafts are indicated by dotted lines m and in Fig. 10 dotted circles n indicate the rotary paths of the rabbles. The speed and direction of rotation may be varied as required, and the rotary movements may be either intermittent or continuous. 29 designates a form of mechanical raking arrangement on the slope j which we preferfor the final stage of the manipulation of the charge. A side elevation of the device 39 is shown in Fig. 9' in which a series of arms 9 are mounted on cross bars 7" and suitably spaced thereon so that the paths of successive arms do notcoincide.

The action of the furnace and its mechanical apparatus is as follows 2-- The charge of lead ore is fed in crushed or'powde'red form into the furnace through hopper hand is carried along by the rabbles or rakes and distributed over the hearth so that it is eXposedin the front part of the chamber to the required temperature 600 to 650 centigrade and the required atmospheric or oxidizing conditions for the roasting of' the ore, the temperature being adjusted by the dampers c and the atmosphere by the air inlets e or e Owing to the arrangement of the various parts and features of the furnace the treatment of the ore inthe front part of the chamber is distinct and separate from the treatment in the farther end. The air entering through the inlets in the front part and the fumes and gaseous products formed are carried away through the pipe 9 and do not penetrate to the farther end of the chamber (Z. The gaseous products from the farther end may be partly drawn through the by-pass g to the pipe 9 instead of traversing the front part.

The speed of shifting of the charge in the traverse 'of the same through the front part of the chamber is regulated so that the charge is sufficiently roasted before passing into the farther end. In the farther end of the chamber to which air is not admitted but which is filled with the non-oxidizing fumes given oft by the treated ore, the temperature is increased to the required extent in order to bring about the required reaction between the lead sulfid, lead oXid and lead sulfate produced by the roasting process. In this part of the process (as is well known) the charge tends to become plastic but by close control of the furnace temperature and suitable manipulation, it is prevented from becoming too soft. Other control or correction of the smelting reaction or of the plasticity of the charge may be made if required by means known in the art, for instance, by the addition of powdered coal, lime, etc., introduced through the door 7. The action of the rabbles, in addition to causing the charge to traverse the hearth forms paths therein which allow the lead produced by the reaction to become disentangled from the residual slag, and on reaching the slope 9' a proportion of the metallic lead is free to run down into the lead well Z. The slag together with separated lead is then carried by the mechanical raking device 20 up the slope 7' in such a manner that the plastic mass while being drawn up the slope is closely channeled by the arms q thereby allowing the remainder of the lead to be freed from slag and to run down into the lead well Z. The'residual slag gradually reaches the upper ridge of the slope j and falls intothe slag pit 7a. The lead on one side of the furnace and the slag on the other are drawn off preferably 1 at intervals through suitable tapping holes 8 and in a well'kn'own manner.

stantially higher temperature than the smelting chamber of the feed portion thereof, controllable means for admitting eXte-- rior air direct to said feed portion'and means for extracting products of combustion from said feed portion and substantially preventing access of air or the said products to said discharge portion.

2. In a furnace forthe continuous smelting of ores in a single operation, the combination of a relatively long externally heated smelting-chamber, means for feeding a charge of ore into one portion of the chamber, means for maintaining the other portion of said chamber at a substantially higher temperature than said feed portion thereof, controllable means for admitting exterior air direct to said feed portion, means for extracting products of combustion from said feed portion and substantially preventing access of said products to said other portion, means for automatically rabbling the ore and shifting same along the chamber to the 'farther end thereof, and means at said farther end for separating the molten metal from the slag.

3. In a furnace for the continuous smelting of ores in a single operation, the combination of a relatively long externally heated smelting-chamber, a hearth in said chamber.

means for maintaining one portion of said chamber at a substantially higher temperature than the other portion thereof, controllable means for admitting air to said other portion,'means for extracting products of combustion from said last mentioned chamber-portion and substantially preventing access of said products to said first mentioned portion, a partition wall partially dividing the chamber into the two portions aforesaid,

means for feeding a charge of ore into the chamber at one end, means for automatically rabbling the ore and shifting same along the hearth to the farther end of said chamber, and means at said farther end for separating the molten metal from the slag.

4C. In a furnace for the continuous smelting of ores in a single operation, the combination of a relatively long externally heated smelting-chamber, a hearth in said chamber having reversely inclined surfaces at the rearward end, means for maintaining the forward portion of said chamber at a substantially lower temperature than the rearward portion thereof, a partition wall partially dividing the chamber into the two portions aforesaid, means for feeding a charge of ore into the chamber at its forward end, and means for automatically rabbling the ore and shifting same along the hearth to the rearward end of said chamber, said rabbling means conducting the slag up said inclined surfaces while permitting the molten metal to gravitate down same.

5. In a furnace for the continuous smelting of ores in a single operation, the combination of a relatively long externally heated smelting-chamber, a hearth in said chamber, means for maintaining one portion of said chamber at a substantially higher temperaturethan the other portion thereof, controllable means for admitting air laterally to said other portion, a valved pipe extending across the chamber and having openings into that part thereof to which air is admitted, means for extracting products of combustion from said last mentioned chamberportion and substantially preventing access of said products to said first mentioned portion, a partition wall partially dividing the chamber into the two portions aforesaid, means for feeding a charge of ore intothe chamber at one end, means for automatically rabbling the ore and shifting same along the hearth to the farther end of said chamher, and means for separating the molten metal from the slag including relatively sloped parts of the hearth up which the slag is conducted by the rabbling devices and down which the molten lead gravitates.

In witness whereof we have signed this specification in the presence of two witnesses.

Witnesses L. L. BEoH'rAN,

C. A. NEALE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

- Washington, D. G.

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