US902047A - Liquation-furnace. - Google Patents

Description

R. BAGGALEY, C. M. ALLENG: E. LINDQUIST.

LIQUATION FURNACE.

APPLICATION FILEDAUG. 7, 1905.

Patented 0ct.27,1908

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R. BAGGALEY, G. M. ALLEN & E. W. LINDQ UIS T.

LIQUATION FURNACE.

APPLICATION FILED AUG.7, 1905.

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I INVZETOR I R. BA'GGALEY, G. M."ALLEN.& E. W. LINDQUIST.

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APPLICATION rum) AUG.7, 1905.

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UNITED STATES PATENT OFFICE.

RALPH BAGGALEY, OF PITTSBURG, PENNSYLVANIA, CHARLES M. ALLEN, OF LO LO, MONTANA, AND EDWARD W. LINDQUIST, OF CHICAGO, ILLINOIS.

LIQUATION-FURNAGE Specification of Letters Patent.

Patented Oct. 27, 1908.

Application filed August '7, 1905. Serial No. 273,051.

T 0 all whom it may concern:

Be it known that we, RALPH BAGGALEY, of Pittsburg, Allegheny county, Pennsylvania, CHARLEs M. ALLEN, of Lo Lo, Missoula county, Montana, and EDWARD W. LIND- QUIST, of Chicago, Cook county, Illinois, have invented a new and useful Liquation-Furnace, of which the following is a description, reference bein had to the accompanying drawings, in which- Figure 1 illustrates a longitudinal cross section on the line A-A of Fig. 2 of our preferred form of apparatus; Fig. 2 illustrates a cross-section on the line BB of Fig. 1. Fig. 3 illustrates a longitudinal cross-section of an alternate form of ap aratus on the line 0-0 of Fig. 4. Fig. 4 llustrates a crosssection on the line DD of Fi 3. Fig. 5 illustrates a cross-section on th'fiine EE of Fig. 3.

The object of our invention is to provide suitable apparatus in which to successfully perform a new process of simultaneously smelting and extracting values by liquation or sweating from a large proportion of ores in which actual fusion is not necessary to obtain the result stated. This result is cheaply accomplished because the use of carbonaceous fuel is unnecessary. It renders available for commercial use vast bodies of lowgrade ores that are now worthless.

Our present invention provides apparatus for the purpose that remams constant in size, conserves the heat produced by the process and is practically indestructible, ordinary wear and tear excepted.

To start the process in the apparatus it is necessary to provide a bath of molten matte preferably derived from an outside source, although it may if preferred be melted within the vessel itself. It should be sufficient to fill the vessel up to the level of the overflow spout, and it is preferably derived from a simple melting with the least possible concentration of ores that are rich in iron, sulfur and other oXidizable elements and compounds. A com erting blast is then driven into the bath of molten matte, which produces heat, and thereafter ores are fed into the apparatus either continuously or intermittently, as may be preferred. If increased heat is desired in the bath, sulfids are fed. If mineral values are desired, these are usually best obtainable from ores of a silicious nature. Care should be taken to provide and maintain a molten bath that contains sufficient iron, sulfur and other oxidizable elements and compounds to constantly supply the. heat necessary to produce success. Thereafter silicious ores are fed into the furnace and these are fused to the point where the iron in the matte after oxidation will form selective slag at minimum tempera tures (much less than the temperatures that ordinarily prevail in blast furnace work) and thereafter a greateXc-ess of silicious ores may be fed onto the molten bath, which float submerged or partially submerged in matte the entire length of the vessel, subjected to the heat and the agitation produced by a converting blast, so that their mineral contents usually existing in the form of occluded particles of sulfid, are sweated out, join the molten bath of matte and are recovered, while the liquated, worthless, silicious shells are discharged with slag and matte into a forehearth at a lower level. In the latter vessel the matte-prills are very thoroughly separated from the worthless slag and silicious ore-shells under favorable conditions that guarantee a thorough recovery. I

We know that'the liquating or sweating out of mineral from various cupreous materials is not a new art in metallurgy, if carbonaceous fuel be utilized to produce and to maintain the necessary heat. It is however radically new and is much more economical to practice the liquation in the apparatus described in our resent invention in which no carbonaceous uel is used. In using this apparatus we preferably crush the ores to a small size, say to the size of a walnut, preheat them to a tem peratureless than that at which sulfur fuses, and deliver them into the furnace as illustrated in the drawings. The fines we treat for the thorough recovery of their contained values, preferably as described in U. S. Patent No. 766,654, issued August 2nd, 1904; in serial application No. 235,418, filed December 5th, 1904, or in other ways. Converter slags may also be delivered into this apparatus, as a thorough, quick and economical means of extracting their contained mineral values. I

Our preferred form of apparatus as shown in Figs. 1 and 2, is at all times fixed and immovable. It is emptied through the matte tap-hole 24 in Fig. 1, on the bottom level of the furnace, should a stoppage render this necessary.

Our alternate form as shown in Figs. 3, 4 and 5, is capable of being inverted and emptied through the nose or throat, should occasion require.

The vessel, shown in the drawings may be longer or shorter. That illustrated in Fig. 1 is preferably 40 feet in length and 8 feet in diameter. That shown in Fig. 3 is 30 feet long and 8 feet in diameter. The greater the length of the apparatus, the longer will be the travel of the floating ore immersed in the bath, from the point of entrance at one end to the point of discharge through the overflow-spout at the other end.

Ores as found in nature are quite different physically. Some will yield up their values by liquation more quickly than others. The length of the vessel must be governed by the characteristics of the ores to be treated. The latter must remain in the bath for a long enough period to have their occluded minerals separated from the gangue, so that they will join the molten bath of matte, before the worthless silicious shells are discharged into the forehearth, otherwise a useless waste of values will occur. The difference in char-- acteristics of the ores therefore must regulate their sojourn in the molten bath, and this sojourn can alone be governed by the length of the furnace and the rate of feed. It will he found cheaper in practice to increase the length of the furnace, rather than to reduce its producing capacity by checking the feed. The rate of feed may be regulated as desired. Within certain limits a long travel for the floating ore is desirable, but no good can result from making this travel greater than is found in practice to accomplish a clean separation. The size of the vessel will govern the volume of initial bath, 1

which must cover the convertingtwyers to start the process. An adequate volume of blast must also be provided. This apparatus may be supplemented with a basic lining, such as magnesite, chrome, etc., if preferred. We have found the first cost of these if of good quality, to be very great, and we have also found that a certain appreciable dissolving action occurs which in time will demand renewal. This produces a current expense for repairs that we do not consider necessary. We have found that if metal walls of sufficient bulk or thickness be provided which bear the correct relative proportion to the molten hath, no appreciable dissolving action occurs. The vessel thus becomes practically indestructible, ordinary wear and tear excepted. These walls may be made of solid blocks 12, 18 or 24 inches in thickness. They may be made thicker or thinner without departing from the spirit of our invention. We have found that these heavy metal walls cannot be injured by service such as this. Only two conditions could in time produce chemical reactions that would injure or destroy them. For instance, if moisture were present, SO would be formed and this would corrode them. Moisture in the interior of this vessel to an injurious extent is physically impossible, with high temperatures. This is particularly the case if all moisture be expelled from the ores before they are delivered into the vessel. Another condition that could work injury to the walls would be in the event of their becoming heated to a temperature equal to that of the molten, bath. This is also a physical impossibility. It is to prevent this that we use blocks of whatever thickness may be found in practice to be necessary. If the block be made sufficiently heavy, its chill will form a protecting layer or skull from portions of the molten bath itself and will maintain this during the continuance of the process. Such skull will be thinner than that formed in the ordinary water-jacket blast furnace. It becomes at once a non-conducting interior wall of the best composition for the purpose, and it automatically repairs itself, if necessity requires. This provides a constant protection against erosion or injury.

Our object in using heavy metal blocks in lieu of water-jackets is because the former conserve and retain the internal heat that is so important to the successful practice of the art. ater-jackets on the contrary, by reason of the heavy, continuous flow of cold water through them, abstract and dissipate the internal heat. Such loss is a serious injury to our process, when we rely alone on heat that is produced from the natural fuels in the ores. In the case of blast furnaces, operated with carbonaceous fuel, such loss of internal heat, although commercially unwise, from a purely metallurgical standpoint is not so serious, because this may be compensated for by an increased consumption of coke and by an augmentation of the blast. Even in the blast furnace, the use of waterjackets results directly in an unnecessary consumption of coke. It is believed that if the heat-dissipating effects of water-jackets in blast furnaces could be avoided, it would make it possible to smelt ores with 5 per cent. of coke, where 20 per cent. is now demanded.

While we describe our preferred form of 4 For this reason it will usually not require much. punching of the twyers which will or- V dinarily keep themselves free and clean while operating on such a low-grade bath, but as an apparatus of this description, even 30 feet in length will require some 60 twyers, pref erably 1-55 inch in diameter, in operating it we preferably utilize a mechanical twyerpuncher such as that described in application Serial No. 260,212, filed May 13th, 1905.

In the fixed liquation furnace illustrated in Figs. 1 and 2, the discharge of hot gases produced in large volume by the converting action, find their escape through a throat or stack 28, Fig. 1, at the end immediately over and around the slag-overflow. The object of this is to provide and maintain great heat above the level of the floating ores until they are finally discharged into the forehearth. The temperature of these gases will always be higher than that necessary to separate the sulfide and minerals from the'floating ores. These gases will be under considerable pres sure and this will help to maintain a high temperature.

6 in the drawings illustrates the bottom, side and end walls in each type of apparatus. These blocks may be composed of copper, wrought or cast steel, wrought or cast iron, or other metal. Their thickness is intended to bear such a relative proportion to the molten bath that the chill of the block will continuously prevent the temperature of the inside surface fi'om rising to a point where it would be possible for the metal of the block to unite with the molten material. For instance, if these blocks were made siX feet thick of solid metal of any kind, it will be apparent that the inside surface could never rise in temperature to a point where fusion would be possible. Our investigations have shown that in ordinary service and for ordinary purposes, twelve inches of solid metal is sufficient to accomplish the desired result.

The apparatus illustrated in Figs. 1 and 2, as well as the apparatus shown in Figs. 3, 4. and 5, being long, in order to provide a long travel for the floating silicious ores while subjected to the sweating or liquation action of the molten bath, will require a large volume of molten matte to fill them to the level of the overflow. In the apparatus illustrated in Figs. 1 and 2, which remains permanently in a fixed position, it may be found desirable to utilize blocks that are 18, 24 or even 36 inches thick. Owing to the fact that the apparatus illustrated in Figs. 3, 4 and 5 is intended to be inverted should occasion require, it is desirable that its weight should not be greater than that found essential in conducting the process continuously without injury to the walls.

7 illustrates heavy metal sectional covers that may or may not correspond in width with the heavy block walls; These covers are capable of being secured in position as shown in Figs. 2, 4 and 5, and may be re moved shduld repairs be necessary or an entrance into the interior of the apparatus become desirable.

8 in Figs. 3 and 4 illustrates the vent, throat or nose for the escape of hot gases.

9 in Figs. 2, a and 5 illustrates the wind-box and twyer. If a cardboard bottom piece be provided in the wind-boX underneath the orifice of each twyer, it will be found con venient, because should molten matte escape, this will quickly burn out and allow the matte to flow in a continuous stream where it would otherwise congeal and fill the wind box if this provision were not made.

As the apparatus illustrated in Figs. 1 and 2 is permanently fixed, it is impossible to raise the twyers above the level of the molten bath and thus to save the orifices from filling with chilled matte or slag. During the fill" ing of this apparatus and later as a means of regulating the volume of blast in each twyer, metal bars or plugs are preferably provided (not shown in the drawings) which may be inserted into any or all of the orifices. These are made somewhat less in diameter than the orifices, so that when they are extracted the blast can pass freely around them and prevent the matte from following the bar out and chilling. For instance if the twyer aperture be one inch in diameter, a round bar %-inch or preferably- 52-inch may be used.

10 in Figs. 3 and 5 illustrates the power mechanism for inverting the vessel when it is desired to empty it.

1] illustrates the entrance for the ore charges. These should be preheated before delivery into the apparatus to a degree less than the fusion oint of sulfur. This preheating will eXpe the moisture and will materially augment the efficiency and the producing capacity. We prefer preheating them for reasons of economy, by means of the waste gases produced by the process. Other means of preheating may be utilized without departing from our invention. The charges may be delivered into the apparatus without preheating and a good efficiency may thus be secured.

12 in Figs. 2 and 5 illustrates an automatic ore-feedingdevice that continuously or intermittently feeds the charges at the rate of speed desired. Other feeding devices may be utilized for the purpose. ratus is utilized to best advantage where the ore charge has not been preheated, because if used it necessarily permits the loss of some of the heat.

26 in Figs. 2 and 5 illustrates one form of preheating oven for the charges when the waste hot gases are utilized and when the ore is subsequently delivered by a mechanical device into the furnace. It is shown by way of illustration, because it will be apparent Such appathat in passing through the mechanical feeder the heat of the ore will be to a certain extent dissipated.

11 in Figs. 3 and 5 represents the feedhopper arranged so that it may be raised or lowered to permit inverting the apparatus. It is preferably lowered into the throat at 13 in order to prevent wasting the ore and to prevent the escape of hot gases at this point when the furnace is in operation.

14 in Figs. 3 and 4, illustrates a reversible heavy metal pouring lip intended to prevent the present expense of renewal due to the cutting action of the molten bath when poured. This ring may be placed in many different positions thus presenting new faces for the cutting action without renewal.

15 in Figs. 1 and 3 illustrates the overflowspout which is preferably water-jacketed. The volume of material that passes through it is very great, and it is desirable that it be watenjacketed in order to prevent expensive renewals due to the cutting action of the flowing material.

16 in Fig. 3 illustrates a practically airtight metal drop-tube through which the molten slag and matte and the liquated ore flow together out of the overflow spout down into the forehearth. It will be noted that the level of the bath cannot exceed that shown at 17. This is purposely provided to afford a free discharge for the matte, slag and liquated silicious ore into the forehearth; to absolutely prevent any trapping of the blast such as prevails in ordinary blast furnace practice; to prevent the accumulation of a ody of floating slag in the apparatus such as always exists in any form of apparatus where the blast is trapped. Should a body of floating slag accumulate in this furnace, it would separate the floating ore from the body of clean matte and as a consequence it would impair the efficiency.

18 in Figs. 1 and 3 illustrates an opening through which the overflow spout may be watched by the operator and when necessary may be quickly, conveniently and thoroughly rodded. This opening affords means for raking out and dropping into the forehearth any chilled accretions that may form. The opening is provided with a heavy, circular, metal door 23 which may be made of any convenient size and may be rolled to one side as a means of opening it. Should chilled accretions form on its inside surface, they may be broken so that they will drop into the forehearth by en aging the lugs 22 with a rod or bar and thus revolving the door. A powerful leverage is thus provided that will break loose such accretions.

19 illustrates a congealed slag covering which forms a practically air-tight union with the air-tight metal drop-tube at 20. When the process is started into operation and when sufficient matte and slag have acprovides a long travel for the slag and matte in molten condition and for the floating liquated ore through the forehearth and underneath the congealed slag covering, in order thus to secure a further separation of all mineral and matte. This has the efifect of conserving the heat to a much greater degree than exists in present practice; it causes an exceptionally clean separation of all matte prills that may be mingled with the slag, and, owing to the intense heat and the consequent fluidity of the slag, a better percentage of separation occurs. By this means the floating lumps of silicious ore are also afforded additional opportunity for sweating or liquation under favorable conditions. WVhen ultimately discharged from the forehearth, both the molten slag and the floating ore lumps are exceptionally clean.

The forehearth is preferably constructed of heavy metal blocks of sufficient bulk to withstand the service without injury and without renewal. We have found that these conserve and husband the heat of the molten bath which is very desirable in producing a clean separation. We have found that where brick forehearths are used, they are soon eaten out by the corrosive action of the iron in the matte. For this reason expensive renewals and frequent stoppages of the smelting process are demanded. here a water-jacketed fOI'GlleitItll of any kind is used, the chilling action of the constantly flowing water through the jackets is so great that it rapidly abstracts heat from the molten bath, prevents a clean separation and causes the matte to solidify continuously and to build up on the floor of the forehearth, so that in a short time the smelting operation must be stopped in order that this great congealed mass may be dug out at a heavy expense. Either type of apparatus described in this application is especially fitted for use not only in extracting the mineral values from low-grade silicious ores by the liquation or sweating process, but at the same time in producing a molten bath of low-grade matte, say one never exceeding 25 per cent. in tenor, for subsequent use in the process of treating ores by dissolving them in a molten bath as described for instance, in United States Patent No. 766,654, issued August 7th, 1904.

24 in Fig. 1 illustrates a matte tap-hole at the lowest level of the furnace. It is preferably water-jacketed, to successfully withstand the cutting action of the flowing molten bath. It is only intended to be used should it become necessary from any cause to discharge the contents of the furnace. This matte-tap is so arranged that it can be plugged with clay etc. from time to time during the emptying process. In this way the matte is preferably drawn oil in batches into suitable ladies and immediately transferred to our secondary converters, where it is blown at once into blister copper. Should this furnace be emptied after the matte has been completely drained out and after as much of the top layer of slag and floating silicious ore has been similarly drawn out as will flow, it is then cooled by permitting the matte-tap to remain open and allowing a current of air to pass entirely through the vessel and out of the stack.

The apparatus shown in Fig. 1 is provided with a permanent stack through which the hot gases under considerable pressure may escape to the atmosphere or to the preheating fines or ovens, or to a system of dust chambers, as may be preferred.

27 in Figs. 2 and 5 illustrates an orifice separate from the ore-feed. It is utilized for the delivery of molten converter slags, molten matte or other molten material. It

generated in large volume so long as the smelting action continues.

Doubtless many modifications in the details of this apparatus will naturally suggest themselves to those conversant with the art.

What we claim is:

A converter having an ore-feeding opening, a matte outlet opening, blast twyers, a.

preheating chamber, means for delivering the hot gases from the converter to the preheating chamber, and means for delivering the preheated ores to the feeding opening; substantially as described.

In testimony whereof, we have hereunto set our hands.

RALPH BAGGALEY. CHARLES M. ALLEN. EDWARD W. LINDQUIST. Witnesses:

FRANK L. RILEY, WILLIAM M. KIRKPATRICK.

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