US1528155A - Process in the roasting, calcining, decarbonization, and desulphurization of carbonates, sulphide ores, and other materials, and apparatus therefor - Google Patents

Description

. W. LANYON Y PROCESS IN THE ROASTING, CALCINING, DECARBONIZATION, AND DESULPHURIZATIQN OF CARBONATES, SULPHIDE ORES, AND OTHER MATERIALS, AND APPARATUS THEREFOR Filed Oct. 51, 1921 2 Sheets-Sheet 1 Mar, 3, 1 925. 1,528,155

' W. LANYON PROCESS IN THE ROASTING, CALCINING, DECARBONIZATION, AND DESULPHURIZATION OF CARBONATES, SULPHIDE ORES, AND OTHER MATERIALS, AND APPARATUS THEREFOR Filed Oct. 51, 1921 2 Sheets-Sheet 2 Patented Mar. 3, 1925.

UNITED STATES PATENT OFFICE.

WILIIAH LANYON, OF ST. LOUIS, MISSOURI.

PROGES IN THE BOASTING, GALCINHG, DECARBONIZATION, AND DESULPHUBIZA TI [ON OFGARBONATES, SULPHIDE ORES, AND OTHER MATERIALS, .AITD APPA- BATUS THEREFOR.

Application filed October 31, 1921. Serial- No. 511,090.

ification containing a full,-clear, and exact description, reference being-had to the accompanying drawings, forming a part hereof. My invention relates to certain new and useful process in the roasting, calcining,

decarbonization and desulphurization of carbonates, sulphide ores and other materials, and apparatus therefor, and has forits primary objectthe subjection of ore or the other materialsdirectly to highly heated air as either the sole or preponderating source of heat, to fully and efiiciently perform the operation. My invention is especially designed for the desulphurization. of ores, and particularly zinc sulphide ores.

.My invention further consists of certain improvements in the apparatus in. connection with the revolving or rotary furnace hereinafter referred to, and illustrated in the drawing, Fig. 1, and used in connection with the operation of the method or process above referred to.

In carry ng out my process it may be applied to any of the well known types ofroasting furnaces now known to -the art, with more or less advantage in the results, but I deem it-tobe especially ap licable to the revolving, or rotary type of urnace.

The illustrations disclose two types of furnace by means of which my process-may be carried out, Fig. 1 being the rotary type and Figs. 2 and 3 being what is denomi nated in the art of zinc metallurgy as a multiple hearth zinc-ore roasting furnace.

Fig. 1 is a longitudinal sectionalview of a rotary type of furnace; and Figs. 2 and 3 are the multiple hearth type, in which Fig. 2 is a section taken on the line 22 of Fig. 3, and Fig. 3 is taken on the line 33 of Fig. 2.

Referring to the drawings: 4 indicates the roasting d um preferably 13 of the drum projects.

air heating chamber in which are locatedair coils 19, or other means of heating the circular in cross section, which has a lining of refractory material 5. The drum 4 is provided with rings 6, which rest on supporting rollers 7, for holding the drum in the proper position.

Mounted on the drum 4 is the gear wheel I 8, meshi'ng with the pinion 9 driven by a motor or other suitable source of power, 10.

-By means of this construction the drum 4 ma be rotated as desired. The drum 4 is provlded with a plurality of "openings 11 for drawing out samples of the ore at any desired intervals of iLImGOI place, also for the purpose of taking the temperature within the furnace, also for the introduction of air at any desired temperature, and measuring the drum.- 4

In the illustration (Fig. 1), 12 indicates the supply or receiving end, and 13 the discharg'eend, the ore or other material being-fed 'into the roasting drum by means of the hopper and conducting pipe 14. i The supply or receiving end 12 is provided with a beveled inwardly projecting shoulder v15 for preventing the material under treatment from being discharged from the receiving end of the furnace. This shoulder has, another function, which will be here inafter described.

16 indicates the air heater, which may be made of any suitable construction, and

pressure of the gases within the may be of the continuous counter current type or in. duplicate or triplicate alternating hot air stove type, and is provided with an outlet into the superheated air chamber 17, into which the discharge end 18 indicates the air. As the process or manner of heating air to a high temperature is so Well known, and is not made a matter of claim in this invention I deem it not necessa to go into a. detailed description of suc apparatus there being innumerable styles and types of such furnaces in operation in metallur ical works.

he cold air, atmosphere, is fed into the I ferred to.

'lhan that temperature is required.

surrounding the air ducts. In practice in the desulphurization of ores, and to achieve my object, it is necessary to supply the heatod air to the roasting chambers to at least-a temperature of 1150 degrees Fahrenheit, and usually'and chiefly a much higher In practice the air heated to the temperature required to suit the material under treatment in the furnace in the drum is discharged into the drum 4 from the air chamber 17 unlformly and under perfect mechanical control, preferably at aepressu're in excess of atmosphere, which pressure may be at-- tained at will through the use of the blower 20 supplying the air, and the curtailed outlet-created by the shoulder 15, before re- The chamber 21 is designed {to receive the exit gases from material underwith the gate 26 for controlling the letting its side walls with openings 31 and 32, from.

out of the burnt product and closing the chamber 17 from the outside air.

In Figs. 2 and 3 I have shown a multiple hearth type of reverberatory ore roasting furnace used for the desulphurizing of zinc sulphide ores, which consists of the roasting furnace 27, and the hot air stove or air heating furnace 28, the two being connected together by means of, the passage flue 29, opening into the highly heated air chamber 30. This chamber is provided in which the heated air passes into and over the hearths or floors 33 on which the ore is resting. It will be noted in this connection that the openings 31 are larger than the openings 32, the idea h'eingthat in practice the greater amount and-perha s all of the heatedair will preferably no admitted through openings 31, and the openings 32 are provided only for use at discretion, as the character ore and heat of the furnace may require, said openings 32 being con trollable toan degree'of opening. or to closing of them off entirely through the door openings .37. oppositeto openings 32. Above the air chamber 30 is the waste gas fiue'34. receiving the waste gases from the top orehearths through openings 35. and onducting them thence to chimney-flue 35. In flue 35 is a damper shown as 36. for regulating the outlet of the furnace. and passage of air andgases through the furfi'om which it- 'the entire furnace.

nace. This dam er may be difi'erently".l ocated or of a di erent style, any common place damper method will achieve the'oblowermost hearth and is't en removed from the furnace by raking it down through the passages 38 whichlea'd to any suitable storage compartment.

In carryingoutmy proce'ss or method. particularly with relation todesulphurizing ofores, in both types of furnace shown. or other types] commonly used i'n'the art that portion ,of the ore under treatment which possesses the least combustible qualities is subjected to the air mosthighly heated, direct from the air heater;

' As the air progresses through. the furnace it. comes in contact with ore containing gradually increasing combustible and 'heat producing qualities, which tend'decidedly to-mainta-in the original temperature and producea comparatively uniform and prop'-' er temperature continuously throu hout- As previously re erred to, the characteristic feature of my process is the use of 'highly heatedair, preferably solely, but.at least in a measure to constitute the major or preponderating heat agency, as the oxidizing agent. particularly 3 in the desulphurizing of sulphide ores particularly zinc sulphide ores. In case the resultant gases are to be used for the manufacture of. sulphuric acid, or other sulphurous or sulphuric uses. it isrequisite that none of the 'oxides of carbon be present in them. Again in cases where the-sulphur gases are not to be utilized, but wasted. it is desirable. if possible to exclude all fuel gases from contact with the are under treatment. as it'is well known that the carbon and hydrogen in them under heat and contact with the metal oxides tends to burn up or volatilize'some of the metal values. which are thereby lost to the outside atmosphere. whereas in an atmosphere of pure :iir volatil'ization seldom occurs. and only at such..extremelv-high temperatures as never or selddm, and then not necessarily attained.

, Regardless of which type of furnace is employed in carrying out my process. the ore is subiected to an atmosphere. preferahlv of highly heated air onlv. or an atmosphere highlv heated in which the majority or preponderance of heat is su plied by highlv heated air. and while I t 0 not deem it as obligatory. (as fair to good results may be had at atmospheric pres- I sure) I consider it as helpful and beneficial to use the highly heated atmosphere'under pressure, in that it causes the heated air to more, thoroughly permeate the ore body and assist in its quicker oxidation, and also as preventing any inrush of cold air from without the furnace, through any door or other openings in the furnace structure, thus preserving the heat and protecting it from being diminished by chilling aircurrents from without, and furthermore, in the, rotary type of furnace I am enabled to maintain a back pressure throughout the entire roast- ,ing chamber without the loss of any sulphur dioxide gases.

I have discovered that the rotary type, as described, of furnace is probably the most suitable for carrying out my process, because the material under treatment can be kept continually and uniformly moved about and agitated bylthe revolvin of the drum 4, and thus slowly or quick y but unceasingly presenting fresh particles of the material under treatment to the action of the heat and the oxygen in the highly heated air,

and at the-s ame time advancing by gravitythe material 'under treatment from the feed to the discharge" end of the furnace. The advantages of my process may be briefly summarized as follows: The saving of fuel, owing to the making possible to a greater degree than customary the utilization of the fuel value of the sulphur contained in sulphide ores for their own combustion; the saving of time in theoperation thus increasing capacity of plantinstallation; a more thorough, complete and satisfactory quality of the roast, and more easily attained; in the case of the rotaryfurnace referred to much saving in fuel and labor over any other style or type; supplies the maximum heat in shape of highly heated air where most needed and a substantially uniform heat throughout the roasting furnace; in the case of the rotary furnace referred to much less first cost of installation com ared with other types, particularl the multlple-hearth, firc-fiue-heated-by-con uct'ion types, mostly in use in producing sulphur gases for the' manufacture of sulphuric acid, and furthermore, the possibility of maintaining a back pressure throughout the entire roasting chamberwithout the loss of any sulphur dioxide gases. I

It is obvious that by means of the fan blower 20, and the damper 24, that I can control the volume of highly heated air that is passed through the roasting drum and I can also control the pressure of the highly heated air' within said roasting drum by increasingor decreasing the speed of the blower. Furthermore, I can regulate the intensity of the highly heated air within said chamber in case of overheating by means of the-openings or pockets 11. This being accomplished by stopping the rotation of the drum while the openings are above the ore level, decreasing the speed of the fan blower, and injecting air through said openings or pockets. The temperature of the air may be further controlled by the speed with which it is forced through the hot air furnace by the fan blower, and the temperature of the hot air furnace It will be further observed that when the drum rotates, the entire mass of ore or material under treatment is always presenting a new or fresh surface for the direct action of the highly heated -air,this being in addition to the air which penetrates (due partly to pressure. within the drum) between .the particles of ore, and I am thus enabled to roast much larger particles of ore than where hand or mechanical StllllIlg. 1s employed. and the roasting is done more unlformly. thoroughly, and quickly.

other material being treated. .The other way was accomplished in what are denominated muffle furnaces .in which the required heating medium to perform the operation is supplied by conduction and radiation of heat through brick walls or arches from fire fiues or chambers adjoining the chambers or spaces occupie under treatment and in some cases in addi tion. in these so-called muflle furnaces a smalljamount of weakly heated air was used by introducing it into the ore chambers. But 'in all such cases this weakly heated air was negligible as to the matter of supplying the requisite quantity and temperature of air and heat-such furnaces being dependent "practically entirely on the fire flues referred ployed, all of them show the use of fire gases introduced in ,the ore chamber or fire flues surrounding the ore chamber and for the sole purpose of apply ng the required heat medium for the operation.

According to my im rovement in the method of roasting and esulphurization, of

by the ore ores and like material, I eliminate and make unnecessary the muffle fines or other awkward and expensive ways of supplying the required heating medium and also eliminate the admission of fire gases in the same chamber with the ore gases.

Having fully described my invention, what I claim is:

1. The, process of treating ores and the like, which consists in subjecting them in a furnace to the direct action of highly heated air regulated as to volume and intensity of temperature as the sole heating agent supplied and at the same time constantly exposing a fresh surface to said air.

2. The process of treating ores and the like. which consists in subjecting them in a furnace to the direct action of highly heated air regulated as to volume, temperature, and pressure as the sole heating agent supplied and at the same time constantly exposing a fresh surface to said air.

3. Theprocess of treating ores and the like in a furnace which consists in subjecting the ore mass while under a continuous stream-like movement having a constantly .changing surface directly to highly heated air regulated as to volume. intensity of temperature and pressure as the sole heating agent supplied.

4. The process of desulphurizing ores and the like in a furnace, which consists in subjecting the material while the mass thereof is in motion to highly heated air regulated as to initial temperature, volume, and pressure as the sole initial heating, and ignition agent supplied. the material having the least.

combustible value being subjected to the air having the highest temperature, the temperature of the air and gases in the furnace being thus maintained substantially uniform by the increasing combustibility of the moving mass of material under, treatment.

5. In a desulphurizing furnace for ores, a rotating roasting chamber provided with a restricted inlet and a refractory lining, means for feeding a stream of ore into the restricted end of the chamber. radially arranged pockets carried by the chamber and provided with closures, said pockets adapted to receive a portion of the ore for sampling purposes. means for feeding highlv heated air and regulating the volume thereof into the discharge end of the chamber, and means for regulating the pressure of the highly heated air within the roasting chamber. v j

6. In a furnace for the desulphurization of ores and the like. an unobstructed rotating drum lined with a refractory material having a tapered restricted receiving and a discharge end, a chamber adjacent to and communicating with the discharge end for producing and supplying to said drum a 7. In a furnace for the desulphurization of ores and the like, an unobstructed inclined rotating drum lined with a refractory ma-' terial having a receiving, and a discharge end. a chamber adjacent'to and communicating with the discharge end for receiving and supplying a heating agent composed of highly, heated air of a sufficient-volume and intensity of heat to produce and maintain combustion of the combustible in the ore in the drum as the sole heating agent supplied in the operation, means for supplying highly heated air free from firing gases to said chamber, a chamber for receiving and passing alongthe waste gases connected to and communicating with the ore feeding or receiving end, and means for regulating the escape of waste gases, whereby the pressure of the highly heated air within the drum is regulated. a

8. The process of treating ores and the like, which consists in subjecting them in a furnace while the mass is under continuous movement to the direct action of highly heated air of sufficient pressure to permeate the mass, as the sole ignition agent.

9. The process of treating ores and the like as a continuous operation, which consists in feeding the ore in stream like formation into a regulated blast of highly heated air of suflicient intensity of heat to produce ignition, and of sufficient volume to maintain combustion, and of sufiicient'pressure to permeate the ore under treatment.

10. The process of desulphurizing a mass of ore as a continuous operation, which consists in imparting to the mass a continuous movement and subjecting it during such movement to a blast of highly heated air of suflicient intensity of heat and volume to produce ignition and maintain combustion,

and of sufficient pressure to permeate the mass being treated, whereby a uniform and thorough roast is quickly obtained.

11. The process of desulphurizing a mass of ore as a continuous operation, which con sists in imparting to the mass a continuous stream-like movement having an ever changing surface and subjecting it during said movement to a supply of highly heated air of suflicient intensity of heat to produce ignition and volume to maintain combustion.

12. In a furnace, a rotating roasting chamber provided with radially extending and closure means for i said pockets spaced apart from the exterior surface of the shamber.

13. In a furnace, a rotating roastin chamber provided 'with radially arrange y pockets fonthe purpose of taking out samples of the materials under treatment therein, for takin the temperature thereof, and injecting suc air supplies that might be desirable, and means for opening and closing said pockets.

14.111 a rotating reverberatory furnace,

comprising an unobstructed rotating drum, lined with refractory material, having a receiving and discharge end, a hot air furnace, a chamber adjacent to andcommunicatin said urn ace, for receiving and supplying to said drum a heating agent composed of highly heated air, of sufficient volumeand intensity of heat to produce and maintain combustion of the combustible in the ore in the drum, as the sole heating .agent supplied for the operation, a chamber for receiving and passing along of the waste gases connected to and communicating with the ore feeding or receiving end, a hopper and pipe connection leading into the receiving end of the drum, said drum having a plurality of longitudinally spaced apart radial pockets formed in or on its periphery, said pockets being for the purpose of takmg samples of ore at various oints throughout the length of the drum, a so for taking the temperature within the drum, and for the introduction of air when and where required, means 4 pockets, and a valve controlled means for the roasted product located in the hot air receiving chamber for receiving and discharging the roasted product. 15. The process of desulphurizing a mass of ore as a continuous operation, which consists in imparting to the mass a continuous movement and subjecting it during said movement to a blast of highly heated air under pressure of sufficient intensity of heat and volume to produce ignition and'maim' tain combustion.

16. The method of dcsulphurizing ores which consists in crushing the ore to the desired size; taking a mass of the crushed ore and imparting to it a continuous streamlike and sliding movement so as to produce and present continuously and iusuccessien new surfaces on the mass of ore, and directly and simultaneously subjecting said surfaces to the action of an atmosphere composed of therein, for tak with the discharge end connected tofor opening and closing said highly heated air, or a preponderance there operation.

17. The process of treating ores in a furnace which consists in permeating a portion of the mass of ore with highly heated air as the sole ignition agent while the mass is under continuous movement.

18. The process of'treating ores in a furmice which consists in permeating a portion of the mass while under constant movement with air of sufiicient intensity of temperature to cause ignition and sufficient volume to sustain combustion. v

'19. The process of treating ores which consists in supplying to a rotary furnace a constant supply of sulphide ore causing said ore to travel through said furnace in a stream-like manner having a constantly changing surface, and causin to pass through said furnace while sai ore is in constant movement, a stream of air of sufficient intensity of temperature to'cause ig- 1 constant supply of sulphide or other ore,

causing said ore to travel through said furmice in a stream-like manner having a constantly changing surface, and causing to pass through said furnace in a direction opposite to the travel of said ore while said ore is in constant movement, a stream'ofair of suflicient intensity of temperature to cause ignition of the combustible in the ore and of suflicient volume to support combustion.

21. The process of treating ores and the like which consists in subjecting them in a furnace while, the mass is under continuous movement. to the direct action of a mobile supply of highly heated air as the sole ignition agent supplied and of sufiicientment suflicient to produce a constantly changing mass surface and simultaneously imparting to the 'ore particles a movement sufficient to present the entire surface of said particlesto said air, and simultaneously imparting to the volume of highly heated air a movement in a direction oppositeto the movement of the ore mass.

In testimony whereof, I have signed my name to this specification.

WILLIAM LANYO'N.

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