US2633257A - Process for charging horizontal zinc retorts - Google Patents

Description

March 31, 1953 J. BRUDERLIN PROCESS FOR CHARGING HORIZONTAL ZINC RETORTS 3 Sheets-Sheet 1 Filed Aug. 28, 1948 INVENTOR. imziffirarkrlm u it P March 1953 E. J. BRUDERLIN 2,633,257

PROCESS FOR CHARGING HORIZONTAL zmc RETORTS Filed Aug. 28, 1948 5 Sheets-Sheet 2 14 [mil fflrader/z'w gm am HTTORNE'Y v E M w 7 5 R R w t m; e a m a H ma 7 H 6 an E w. r w 3 2 a m f S Z 5 mir k W i E E J BRUDERLIN PROCESS FOR CHARGING HORIZONTAL ZINC RETORTS March 31, 1953 Filed Aug 28, 1948 Patented Mar. 31, 1953 UNITED STATES PATENT OFFICE PROCESS FOR CHARGlNGjH'ORIZONTAL ZINC RETORTS Emil J. Bruderlin, Amarillo, Teen, assignor to American smelting and Refining Company, New York, N. Y., a. corporation of. New Jersei' Application August 28, 1948, Serial No. 46,617

4 Claims.

This invention relates to the horizontal retort process for reducing zinc ores and more particularly to the manner of charging the retorts, for which operation the invention provides decided improvements.

The conventional, commercial method of charging horizontal zinc 'retorts by shovelling the charge into the retorts is notoriously, though by necessity, a hot, disagreeable jobin fact, it has been difficult for more than a generation for horizontal retort zinc smelters to secure and maintain adequate charger personnel for that reason. Such state of affairs is alleviated by the new charging process of the invention.

As will be apparent as the description proceeds, the process of the present invention affords many advantages in horizontal zinc retort practice, among the more important of which are:

(a) Safety of the chdrger.-When charging by the old, conventional method, the charger must necessarily stand next to the furnace where he is exposed to possible severe injury from burns occasioned by blow-outs. With the new process, the charger performs his 'du'ties'a safe distance away from the furnace. Y

(b) Uniformity of charge throughout all 'retorts in the 'b'locltfiThe new process eliminates the variations encountered when charging by the old method due to such factors as tiring of the charger resulting in the latter retorts being'r'nore poorly charged, the difficulty in reaching the retortsin the upper and lower rows as compared to those in the intermediate rows, etc.

Ease of..charging.---By' the new process, a charger .can readilycharg'e three or four times the number of retorts per shift that he canby the old method.

(it) Density of charge.-An increase in density of charge by thenew process, amounting'to and as high as 18.5% in some instanceshas been conclusivelydemon'strated in plant scale opera tions.

(e) Greater direct metal recovery-.-It has been found that in charging the retorts by the new process, less'blue powder is fcrmediand the direct metal recovery increased by approximately 2.5% to 3%.

Although the novel features which are believed to be characteristic of this invention will be 2 particularly pointed out in the claims appended hereto, the invention itself, as to itsv objects and advantages, and the manner in which it may be carried out, may be better understood by referring to the following description taken in conmotion with the accompanying drawings forming a partthereoi, in which Fig. 1 is a side view of an overhead feeding device and charging machine for practicing the process of the invention, looking toward the face of a horizontal retort zinc furnace,

Fig. 2 is atop view of the machine shown in Fig. I,

Fig. 3 is a section through such machine taken on the line 3--3 of Fig. 2,

Fig. 4 is an end view of the machine. and showing thefurnace and retorts in cross section, and

Fig. 5 is a cross-section of the air inlet end of one of the blow guns of the machine taken on the line 55 of Fig. 1.

Like reference characters denote like parts in the several figures of the drawings.

Referring to the drawings, 10 is a'zinc reduction furnace comprising a bank of four tiers of horizontal retorts l2 and" having a track l4 extending along the face of the furnace on which the charging machine I6 is mounted. An overhead feeding device comprising a belt conveyor land tripper discharge deviceZfl equipped with a spout 22, is provided for delivering charge to the machine 16 at any desired station or the latter alongtrack [4.

The charging machine l6 comprises a housing 24 enclosing an endless, bucket elevator 26 driven by a motor 28, the top of the housing 24 forming a hopper 3!] adapted forregi-stry with spout 22 of feed discharge device 20. A blow box 32, which extends vertically along housing 24 with its upper end in open commumcation with hopper 30, is provided with four blow guns 34 and supports air manifold 36 to which is connected flexible. com pressed air supply pipe 38.

.As will be seen irom Fig. 5, each of the blow guns 34 is provided at one end with a compressed air inlet pipe 40 secured in position with respect to Venturi-like orifice 42 in the barrel of the -blowfgun by bracket Aland set screw 46, the

3 the blow box 32, as shown in Fig. 3 which direct charge from the hopper 30 across the top of the blow guns 34, the barrels of which are cut away on their top portions, as shown in Figs. 4 and 5, to provide charge openings or inlet ports 52. A lowermost baflie 5| is provided in the blow box 32 for directing any charge in excess of that entering the blow guns 34 into the lower portion of housing 24 via port 53. A plurality of inspection and air inlet openings 5e are provided in a wall of the blow box 32 as shown in Fig, 2 and the whole blow box assembly is adjustable vertically by means of a hand wheel 56 operating through reduction worm 58 on hinged support 60 keyed to shaft 62.

At the end of the machine opposite the blow box assembly, there is provided a clean up-or auxiliary charge hopper B4 and belt feeder 68, the latter being driven by a motor 68 and discharging into the bucket elevator 26 via hopper "H! in housing 24. An open inspection door 12 is provided in the side of housing 24 farthest away from the face of the furnace, on which side is also located an electric control switch, generally indicated by it, for the elevator 26 and belt feeder 66, and a master electric control switch generally indicated by 16, for the elevator and feeder aforesaid and for the overhead feeding device which supplies charge via spout 22 to the charging machine hopper 30. details of such electric controls being conventional, same are omitted from the drawing, the positions of switches l4, 16 being shown to illustrate how they, with the air control valves 48,

result in all of the control equipment being within easy reach of the operator. As illustrated, the charging machine is supported by a carriage comprising frame 18 and four flanged wheels 80 which serve to mount the machine on the track it. Means for advancing the machine along track It may appropriately take the form of a fulcrum unit 82 (Fig. 2) manually operated with a bar.

The following will serve to illustrate one manner of charging a horizontal retort, zinc furnace using the process of the invention. The machine I6 is positioned on track [4 at the head end of the furnace it and the blow guns 3t aligned with the first row of retorts l2 at that end of the furnace, vertical and horizontal adjustment of the blow guns beingaccomplished by proper manipulation of hand wheel 55 and fulcrum unit 82, respectively. The charge (zinc sinter and'reduction fuel) for the retorts isdelivered by belt l8 via tripper device 20 and spout 22 to hopper 3i! and thence downwardly through blow box 32 where it is deflected from side to side overinletports 52 by baffles 5B.

As the charge passes downwardly through the blow box, valve c8 of the top blow gun (Fig. 4) is opened thereby releasing air under pressure of say, 80-100 lbs. per square inch, from manifold 36, through air inlet pipe 48 into orifice 42 (Fig. 5) from whence it is circumferentially confined by the wall of the blow gun 3% to form an air blast stream directed at the open mouth of the retort l2. Meanwhile, the charge passing downwardly through the blow box, enters the charge inlet port 52, partially by gravity and partially by suction of the air blast, and is entrained in the air blast stream. Ingress of air from the atmosphere in response to the partial vacuums accompanying the release of the compressed air to form the air blast stream and the entrainment-of thechargetherein at the The wiring pr U1) port 52, is provided by the open rear end of the blow gun where inlet pipe 40 enters same and by the openings 54 in housing 24, respectively.

Upon entering port 52, the charge particles have imparted to them a directional velocity tending to approximate that of the air blast stream in which they entrain, which velocity is sufficient, even though the circumferential confinement of the stream be discontinued short of the retort mouth, to carry the charge particles into the retort cavity where they are deposited to form a retort charge of greater density than that resulting from conventional, commercial manual charging methods. The air of the air blast stream is dissipated to the atmosphere at the retort mouth.

As soon as the retort is filled, which will ordinarily be in about one-half of a minute, valve 43 of the top blow gun is turned off and the next valve 88 opened, and so on until all four retorts in that vertical row are charged. 01? course, the retorts may be filled in any other order desired, or, a plurality of retorts may be simultaneously charged. In event one or more of the retorts is a bit out of line with the others, as occasionally happens, it is only necessary to adjust the position of the air blast stream for that retort by means of hand wheel 56 or fulcrum unit 82, or both.

During the charging operation, the bucket elevator 26 is in operation to pick up any surplus charge which passes the ports 52 and discharges over bafile 5i, through port 53 into the bottom of housing 2 5, and recirculate the same to the blow box 32.

With the first vertical row of retorts charged, the machine it is advanced to the next row and the retorts in that row charged in a similar manner to that heretofore described. This sequence is repeated until all retorts in the furnace are charged. After the machine clears the first few rows of retorts, the condensers (not shown) are affixed at the mouths of the retorts and any spillage of charge cleaned up and recirculated to elevator 26 by way of hopper (i4, belt feeder 66 and hopper 19. When the last retorts have been charged the blow box is raised about 8" by turning hand wheel 56, to provide clearance of the condensers by the blow guns as, and the machine returned on track 14 to the head of the furnace, as is also the overhead feedin device.

While the foregoing illustrates one manner of practicing the invention, it will be understood that various changes and modifications embodying its principles may be made by those skilled in the art within the scope and spirit of the invention as defined by the appended claims. For example, the invention has been described with reference to compressed air to form the air blast stream; however, steam .or other gaseous fluids could be used and, hence, in that sense, are to be considered the equivalent of air.

Various of the advantages attending the use of the new process, such as safety of the charger, uniformity of charge throughout the various retorts, ease of charging, etc. are believed already apparent from-the description. The following comparison of thirteen consecutive cycles on two furnaces conventionally charged and two furnaces charged in accordance with the invention, will serve to illustrate other advantages afforded by the invention such as increased production .as reflected by greater charge density and enhanced emciency of the horizontal retort process itself in reducing the zinc of the charge:

Conven Furnaces tionally Charged Charged by New Furnaces Process Lbs. Charged per Cycle, including Blue Powder 48, 533 53, 808 Lbs. Zn in Charge 29, 980 33, 611 Recovery in Percent 88. 4 89. 1 Lbs. Charged as Charge only 43, 203 48, 885 Lbs. 'nc 26,658 30, 526 Recovery (percent) Direct Met 61. 3 63. 1 No. of Charge Retorts 288 286 Volume per Retort A 2. 33 2. 33 Lbs. per Charge Retort 150 171 Lbs. Charge per Cu. Ft 64. 3 73. 4

That the use of the invention will consistently result in a retort charge of greater density than that of a retort conventionally charged, is well evidenced by the following table showing the ranges in charge density (lbs. charge per cu. ft. of retort volume) for all charging cycles for all furnaces in four months of regular plant operation:

Conven- Furnaces ticnally Charged Charged by New Furnaces Process Month A. 62-69 69-76 t it 2523 28? on 9 Month D 61-69 69-78 In short, even the poorest of the new process charges was the equivalent of the very best of the conventionally charged charges in den- 'Will carry it into the retort, directing said confined stream at the open mouth of the retort in substantial registry therewith, entraining a free falling stream of charge particles inthe so established gas stream, discontinuing circumferential confinement of the gas stream before it reaches the retort mouth at a point sufficiently spaced from said retort mouth to permit the gas to be liberated to the atmosphere in the space therebetween, the position of said point also being such that the velocity of the entrained charge is suflicient to carry it into the retort cavity and deposit it therein, depositing said charge in the retort, and dissipating the on-coming gas in said stream to the atmosphere in the space between said point and the retort mouth.

2. A process for charging a horizontal zinc retort with zinc bearing material which comprises laterally confining a gas stream, directing said confined stream at the open mouth of the retort in substantial registry therewith, establishing above the gas stream a free hailing stream of charge particles, agitating and aerating said free falling stream, directing said stream of particles into said gas stream at substantially a right angle to the path of flow of the latter, and discontinuing circumferential confinement of the gas stream before it reaches the retort mouth at a point sufficiently spaced from said retort mouth to permit the gas in the stream to be liberated to the atmosphere in the space therebetween, the position of said point also being such that the velocity of the entrained charge is sufficient to carry it into the retort cavity and deposit it therein.

3. A process for charging a horizontal zinc retort with zinc bearing material which comprises so releasing as under pressure of several tens of pounds per square inch as to efiectuate lateral expansion thereof to several times its former volume and confining the released, expanded gas circumferentially but without axial confinement to form a blast stream, directing said confined stream at the open mouth of the retort in substantial registry therewith, establishing above the blast stream a free falling stream of charge particles, agitating and aerating said free falling stream, directing said stream of particles into said blast stream at substantially a right angle to the path of flow of the latter and in the zone in which said lateral expansion of the air is efiectu-ated, conveying away from the blast stream any charge unentrained therein, disc-ontinuing circumferential confinement of the blast stream before it reaches the retort mouth at a point sufficiently spaced from said retort mouth to permit the gas in the stream to be liberated to the atmosphere in the space therebetween, the position of said point being such that the velocity of the entrained charge is sufiicient to carry it into the retort cavity and deposit it therein, depositing said charge in the retort, and dissipating the on-coming gas in the gas stream to the atmosphere in the space between said point and the retort mouth.

4. A process for charging a horizontal zinc retort which comprises so releasing gas under pressure or suificient tens of pounds per square inch as to effect lateral expansion thereof to several times its former volume and confining the released, expanded gas circumferentially to form a blast stream, said stream being directed at the open mouth of the retort in substantial registry therewith, establishing above the blast stream a free falling stream of charge particles, aerating said free falling stream, entraining charge in the so established blast stream by directing said free falling aerated stream of charge particles into said blast stream at a point near but past the latters source, and discontinuing the circumferential confinement of the blast stream at a point short of the retort mouth where the velocity of the entrained charge is sufiicient to carry it into the retort cavity and deposit it therein while the gas in the blast stream is dissipated at the retort mouth.

EMIL J. BRUDERLIN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 212,570 Ross Feb. 25, 1879 837,622 James Dec. 4, 1906 851,668 James Apr. 30, 1907 1,530,919 Thomas Mar. 24, 1925 1,815,403 Goebels July 21, 1931

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