US1871657A - Condenser for zinc vapors - Google Patents

Description

Aug. 16, 1932.

E. HI BUNCE GONDENSER FOR ZINC VAPORS' Filed Aug. 30. 1928 3 Sheets-Sheet l INVENTQR 5/1/72 H, BU/VCE BY GMRMWM ATTORNEYS Aug. 16, 1932. 1 E. HLBUNCE 1,871,657,

-' CONDENSER FOR ZINC VAPORS Filed Aug. so, 1928 s Sheet s-Sheet 2 I I INVENTOR 1 EARL H. BU/VCE ATTORNEYS Aug. 16, 1932. E. H. BUNCE 1,871,657

' CONDENSER FOR zmc VAPORS File d Aug. 30, 1928 3 Sheets-Sheet 3 INVENTOR [54/71. H BU/VCE ATTORNEYS Patented Aug. 16, 1932 UNITED STATES PATENT OFFICE EARL H. BUNCE, OF PALMERTON, PENNSYLVANIA, ASSIGNOR TO THE NEXT? JERSEY ZINC COMPANY, OF NEW YORK, N. Y., A CORPORATION .01? NEW JERSEY CONDENSER FOR ZINC VAPORS Application filed August 30, 1928. Serial No. 303,037..

This invention relates to the condensation of zinc vapor, and has for an object the provision of an improved apparatus for condensing zinc vapor. More particularly, the invention contemplates the provision of apparatus capable of efficiently condensing zinc vapor producing during continuous smelting or reducing operations. The invention further contemplates the provision of a condenser capable of fractionally condensing vapors produced during the reduction of zinciierous materials to eliminate certain impurities contained therein and thus provide at least a portion of the product in the form of high grade metallic zinc.

In the customary method of producing zinc by the batch or discontinuous distillation of ore and coal mixtures in horizontal retorts, the cadmium present as a contaminant in most zinc ores tends to distil off from the ore during the first stage of the distillation before the greater part of the zinc. This cadmium tends to condense together with zinc in the form of a high-cadmium zinc dust, which can be collected separately from the zinc or spelter in the first stage of the distillation, by well-known methods. This separate collection of the cadmium-rich blue powder or zinc dust results in a partial elim ination'of cadmium from the zinc metal produced. Such a separate collection of cad'- mium-rich blue powder is obviously impossible in the case of a continuous distillation process, in which cadmium is being continuously distilled. out of the freshly charged batches of ore. The fractionally condensing condenser of the invention makes it possible to substantially eliminate cadmium from the bulk of the zinc metal produced by the continuous distillation of zinc ores contaminated with cadmium.

The condenser of my invention comprises a series of substantially horizontally disposed communicating chambers. Tap holes are provided at suitable points for the removal of condensed metal. The chamber at one end of the series is provided with a passage for the entrance! of the vapors to be condensed and the chamber at the other end of the series is provided with a waste gas outlet. Stag gored openings provide means of communication between the chambers in series as well as means for causing the vapors to follow a circuitous path in their passage through the assembled unit.

The chamber-sot my improved condenser are preferably separately formed and connected together by means of conduits which form passages for the flow of gases between the chambers. The assembled unit comprising a plurality of chambers may be mounted in a casing and surrounded by carbon paste, dust coal, or other suitable heatinsulating or heat conducting material. The separate construction of the individual chambers is highly advantageous, permitting expansion and contraction of the chambers of a unit relatively to each other as a result of changes in temperature, permitting ready substitution of new chambers for worn out or broken chambers of a series, and permitting the lengthening or shortening of a series by the addition I ume successively from the gas entrance end to the gas exit end of the series in substantial proportion to the decrease in volume of the gases as they flow through the condenser.

The gas exit means may be in the form of an ordinary opening in a wall of the last chamber of the series, or one or more upright condensing tubes may be provided in order to increase the condensation area or to permit control of the flow ofgases through the condenser through stack draft control.

The condensing chambers are preferably disposed at a slight angle to the horizontal to cause the condensed liquid metal to flow to the ends thereof. The tap holes are disposed their lowermost end walls.

' maintained in be disposed at different elevations with their axes lying in the same or different planes.

The invention will be better understood from a consideration of the following description taken in conjunction with the accompanying drawings in which are shown several embodiments of the invention, and in which v Fig. 1 is a sectional side elevation of a condenser embodying the invention and comprising a plurality of superimposed chambers decreasing in volume from. the lowermost to the uppermost,

Fig. 2 is a sectional end elevation taken on line 22 of Fig. 1;

Fig. 3 is a plan of a condenser embodying the invention and comprising a plurality of chambers having their axes disposed in substantially the same horizontal plane;

Fig. 4 is a sectional elevation taken on line 44 of Fig. 3;

Fig. 5 is a sectional elevation taken on line 55 of Fig. 3;

Fig. 6 is a sectional elevation of a condenser embodying the invention and comprising a plurality of superimposed chambers-increasing in volume from the lowermost to the uppermost; and

Fig. 7 is a sectional elevation taken on line 77 of Fig. 6.

The condenser illustrated in Figs. 1 and 2 of the drawings comprises a plurality of cylindrical chambers 10 of decreasing diameters from the bottom to the top. The axes of the chambers are substantially parallel and inclined at a slight angle to the. horizontal. The chambers 10 may be conveniently formed of silicon carbide or other suitable refractory material, and they are preferably so arranged and insulated that a definite temperature gradient decreasing from the bottom to the top may be maintained. This temperature gradient may be obtained by suitably regulating the amount of heat insulating material surrounding the chambers.

Conduits ll connect the separate chambers and provide staggered passages for communication between adjacent condensing chambers near the ends thereof. Alternate condensing chambers, beginning with the lowermost, are provided with tap holes 12 in Suitable removable plugs of heat resisting material are position in the tap holes except during tapping operations. Thelowermost condensing chamber is provided with a passage 13 in its uppermost end Wall through which vapors are initiallyvintroduced into the condenser.

The upper portion of the top chamber wall is provided with a plurality of openings 14 which communicatewith a plurality of substantially vertically disposed, condensing tubes 15. The tubes 15 may be dispensed with and an ordinary outlet passage may be provided adjacent the upper end of the the casing through the openings or ports 18 near the bottom. Suitable doors or closure members 19 are provided for closing the openings or ports 18. The thickness of the insulating material may be varied by inserting temporary partitions between the condensing chambers and the walls of the casing.

The condenser illustrated in Figs. 3, 4L and 5 of the drawings comprises a series of chambers 20 disposed at the same elevation and decreasing in size from one end of the series to the other. The axes of the chambers are substantially parallel and inclined at a slight angle to the horizontal. The chambers 20 may be conveniently formed of silicon carbide or other suitable refractory material, and they are preferably so arranged and insulated that a definite temperature gradient from one end of the series to the other may be maintained.

The chambers are connected by means of conduits 21 which provide staggered passages for communication between adjacent chambers. Each of the chambers is provided with a tap hole 22 in its lowermost end wall. The largest chamber of the series is connected by means of a conduit 23' to a retort 24 or other source of vapors. The smallest chamber of the series is provided with a tube 25 which may extend to any desired elevation and which forms an outlet for waste gases.

The chambers are preferably packed in car bon paste 26 surrounded by a steel casing 27. The casing 27 is supported'upon a layer of heat insulating material 30 within a second casing 31. The walls of the casing 31 are spaced from the walls of the casing 27, and the space between the casing walls is filled with dust coal 32. The walls of the outer casing extend above the walls of the inner casing and the space above the inner casing is also filled with dust coal. The casing 31 is open at the top to permit addition or removal of dust coal.

The condenser illustrated in Figs. 6 and 7 comprises a plurality of superposed chambers 33 decreasing in volume from the uppermost to the lowermost. The axes of the chambers are substantially parallel and inclined at a slight angle to the horizontal. The chambers may be formed of silicon carbide or other suitable refractory material, and they are preferably so arranged and ininitial introduction of vapors to be con-- densed. A tube 40 which may extend to any desired elevation communicates with the upper portion of the lowermost chamber and provides a passage for the escape of waste gases.

The chambers are packed in carbon paste and surrounded by an inner casing 41. The casing 41 is supported upon a layer of ins'ulating material 43 within an outer casing 42. The walls of the outer casing are spaced from and extend above the walls of the inner'casing, and the spaces between the casings are filled with dust coal 44. An opening 45 normally closed by a door 46 is provided in-the outer casing to provide for the removal of the dust coal.

In condensers embodying the invention, the decrease in volume of the successive chambers is so adjusted as to be proportionate to the decrease in volume of the gases incurred as they flow through the condenser, a decrease due in part to the removal of metallic vapor on account of its condensation to liquid metal, and in part to the thermal contraction of the gases as they flow from the relatively hotentrance end of the series to the relatively cool exit end of the series.

The angle of inclination of the chambers should be just sufficient to cause the condensed liquid metal to flow readily to the lowermost ends of the chambers.

' In the operation of a condenser of the type illustrated in Figs. 1 and 2 of the drawings, vapor to be condensed is introduced into the lowermost condensing chamber through the passage 13. The vapor which remains uncondensed in any chamber, together with other ases associated therewith, enters the next hlgher chamber through a conduit 11. The gases thus pass from the lowermost to the uppermost condensing chamber and out through the condensing tubes 15 to the atmosphere. The temperatures of condensing chambers and the rate of passage of the gases through the condenser may be soregulated that substantially the entire metallic vapor content of the gases may be recovered in the condensing chambers.

The condensed metal flows to the lowermost ends of the chambers. The arrange ment is such that from those condensers which are not provided with tap holes, the liquid metal may flow through the conduits 11 to chambers which are provided with tap holes. By maintaining the difierent chambers at different temperatures, fractional condensation of the vapors may be accomplished, and a. high grade zinc metal product, practically free from cadmium and similar volatile metals accompanying the gaseous product of the reducing. operation, may be obtained. The lowermost chamber or chambers may be maintained at such a temperature that zinc alone will be condensed, while the uppermost chamber or chambers should be maintained at such a temperature as to condense all the remaining metals.

In the operation of the condenser illus-- trated in Figs. 3, 4 and 5 of the drawings, the vapor to be condensed is introduced into the largest chamber through the passage 23 and follows a circuitous path through the series to the waste gas outlet 25. A temperature gradient which will permit the recovery of the desired number of fractions may. be maintained, and condensed liquid metal may be recovered from each chamber.

The operation of the condenser illustrated in Figs. 6 and 7 is similar to the operation ofthe condenser illustrated in Figs. 1 and 2 except that the gases are introducedinto the uppermost chamber and exhausted from the lowermost chamber, and the temperature gradient decreases from the top to the bottom.

Wheh metallic lead vapor is present in the vapors coming from the reducing chamber, it will be condensed before the Zinc or cad mium. Condensers of the type illustrated in Figs. 1, 2, 6 and 7 may be provided wth a sufficient number of condensing chambers and tap holes to provide for the recovery of a number of fractions. Thus, when lead, zinc, and cadmium are presentin the gases, these condensers may be constructed with additional chambers so as to provide for the recovery of three fractions, two of which will be contaminated with lead and cadmium and one of which will be high grade zinc practically free of contaminating metals. The

1. A condenser for zinc vapor comprising a series of substantially horizontally disposed connecting chambers with a vapor inletv at one end of the series and a waste gas outlet at the other end of the series, the chambers being connected in series by staggered conduits so that the path of the vapor through the condenser unit is circuitous, and being progressively decreased in volume from the vapor inlet end to the Waste gas outlet end.

2. A condenser according to claim 1, in which the gas exit means consists of a plurality of upright condensing tubes adapted to increase the condensation area of the condensor unit as well as to permit control of the flow of gases through the condenser unit.

3. A condenser according to claim 1, in which the chambers are disposed at a slight angle to the horizontal so as to cause condensed zinc vapor to flow to tapped ends thereof.

4. A condenser according to claim 1, in which the chambers are in part at least surrounded by an outer casing adapted to receive heat insulating material in Varying amounts.

In testimony whereof I affix my signature.

EARL H. BUNCE.

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