US1848461A - h bunce - Google Patents

Description

E. H. BUNCE 1,848,463

APPARATUS FOR THE CONDENSATION OF ZINC VAPORS March 8, 1932.

Filed Aug. 30, 1928 2 Sheets-Sheet lNVENTOR HIS ATTORNEYS ///////f////////f//// fff/ /f/ um ...,...H u w l Nimh s, i932. E H, BUNCE 3,848,461

APPARATUS FOR THE CONDENSATION OF ZINC VAPORS Filed Aug. 30, 1928 2 Sheets-Sheet 2 INVENTOR HIS ATTORNEYS Patented Mar. 8, 1932 UNITED STATES PATENT OFFIC EARL H. BUN CE, F PALMERTON, PENNSYLVANIA, ASSIGNOR T0 THE NEW JERSEY ZINC COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY APPARATUS FOR THE CONDENSATION 0F ZINC VAPORS Application led August 30, 1928. Serial No. 303,036,

This invention relates to the condensation of zinc vapor, and has for its object the provision of an improved apparatus for condensing zinc vapor.

One of the objects of the present invention is to provide a condenser capable of efficiently condensing relatively large volumes of zinc vapor. A further object of the invention is the provision of a condenser capable of handling and efficiently condensing a substantially continuous supply of zinc vapor, delivered to the condenser in relatively large volumes batches of ore.

from a continuously operating reducing or smelting furnace. Another object of the invention is to provide a condenser capable of fractionally condensing and collecting impurities accompanying the zinc vapor, such as cadmium. More particularly, the invention aims to provide a condenser capable of eciently condensing the zinc vapor produced by the smelting or reduction in a continuous manner of an agglomerated charge in a vertical retort.

In the ordinary method of producin zinc by the batch or discontinuous distillation of ore andcoal mixtures in horizontal retorts, the cadmium present as a contaminant in most zinc ores tends to distil oi :from the ore during the first stage of the distillation before the greater part of the zinc, as is well-known. This cadmium tends to condense together with zinc in the form of a high-cadmium zinc dust, which can be collected separately from the metallic zinc or spelter in the first sta e of the distillation, by well-known metho s. This separate collection of the cadmium-rich blue powder or zinc dust results in a partial elimination of cadmium from the metallic 'zinc produced. Such a separate collection of cadmium-rich blue powder is obviously impossible in the case of a continuous distillation process, in which cadmium is continuously being distilled out of the freshly charged The method and condenser of the invention' makes it nevertheless possible substantially to eliminate cadmium from the bulk of the zinc produced by the continuous distillation of the zinc ores contaminated with cadmium.

The features of my invention which I consider patentably novel are definitely indicated in the claims appended hereto. The principles of the invention and their operative embodiment in a condenser will be understood from the following description taken in connection with the accompanying drawings; in which Fig. 1 is a sectional front elevation of a condenser embodying the invention;

Fig. 2 is a sectional side elevation of the cordenser, on the section line 2 2 of Fig. 1, an

Fig. 3 is a plan view, partly in section, of the condenser, on the section line 3 3 of Fig. 1.

In the accompanying drawings, the condenser of the invention is shown operatively connected to a zinc distillation furnace of the vertical retort type. Only the upper portion 5 of the vertical retort is shown in the drawings. The active zinc distilling or smelting zone of the retort is within an appropriate furnace structure below the por' tion 5 and not shown in the drawings. The top 6 of this furnace structure supports the condenser as will be more fully described hereinafter.

A transverse vertically disposed partition 7 divides the top of the retort 5 into a charging compartment 8 and a gas-exiting cornpartment 9 having a lateral outlet 10. The charging compartment 8 is closed by a removable cap or cover 11, which is removed, as required, for the charging into the retort of fresh agglomerates of mixed zinciferous material and carbonaceous material. The compartment 9 is permanently closed and sealed Aat the top.

The improved condenser of the invention is mounted on a frame-work 12 supported on the top6 of the furnace structure. The condenser comprises two liquid metal collecting chambers 13 and 14. `These chambers are formed in a built-up brick structure 15 provided with a transverse partition 16.

The structure 15 is built up of temperature-resistant material of good heat conductivity. Silicon carbide is well suited for the purpose. In the condenser illustrated in the accompanying drawings, the structure 15 is built up of silicon carbide brick, while the partition 16 is preferably built of refractory brick of poor heat conductivity. These brick are first treated on a revolving sand grinding` table where all irregularities are eliminated, the contacting surfaces of the brick cut smooth and any faults covered over by the surface glaze revealed and the faulty brick rejected. The brick are then laid with a high grade refractory cement, such as silicon carbide cement, which will bond the brick at the temperature at which the condenser operates.

The structure 15 is trough-like in configuration having a cylindrical bottom with flat side walls considerablylonger than its fiat end walls. The transverse vertically disosed partition 16 is substantially midway Between the end walls and divides the structure into the two chambers 13 and 14.

The built-up brick structure 15 is mounted within a setting of dry loam 17 appropriately confined by an inner sheet metal casing 20. An outer metallic casing 21 is suitably spaced from the inner casing 20 and the space between the two casings is filled with dust coal 22. The amount of coal dust provided in the casing maybe varied in order to vary temperature conditions within the condenser. For that reason the top of the casing is shown open, as indicated in the drawings.

The chamber 13 has a lateral opening registering with the opening 10 of the retort, and these registering openings are lined and connected by a silicon carbide tube or orificeV 23. vThe orifice 23 serves to convey the gaseous'products of the reducing operation from the retort 5 tothe condenser. AThe chamber 13 is also provided with a clean-out opening K lined with a silicon carbide tube 24. The

clean-out opening is in a side wall of thev chamber opposite the gas inlet orifice 23,

and in the'normal operation of the condenser is filled `with a plug of temperature-resistant y material.

A cylindrical tube or tower 25, preferably of silicon carbide, is mounted on top' of the ychamber 13 and in communication therewith.'y

Thel top of the tower 25 is covered and closed by a silicon carbide plate 26. The tower and its cover is enclosed in a layer of dust coal 27, or equivalent heat-insulating means, ap

propriately confined by a cylindrical metal casing 28.

v23 intoy the chamber 13. through the chamber 13 and up the tower 25 A laterally disposed silicon carbide tube 29 connects the upper part of the tower 25 with a similarly disposed, but smaller, tower 30 mounted on top of the chamber 14 and communicating therewith. A still smaller tower 31 is also mounted on top of the chamber 14 and in communication therewith, and preferably is of graduallyy decreasing cross-sectional area from the bottom towards the top. The towers 30 and 31 are surrounded with dust coal or other insulating material conned by cylindrical casings, as described in connection with the tower 25. The top of the tower 30 is closed by a cap 26', while the top of the tower 31 is open to thev atmosphere.

The decrease in diameter of the successive condensing towers is preferably so adjusted as to be proportionate to the decrease in volume of the gases incurred as they iow through the' condenser, a decrease due in part to the removal of zinc vapor on account of its condensation to liquid metal, in part to the thermal contraction of the gases as they flow from the relatively hot entrance end of the condenser to the relatively cool exit end.

The condenser of the invention is especially adapted for the fractional condensation of the metallic vapors resulting from the reducing operation. To this' end, the chamber 13 is provided with its own molten metal tap hole 32 and the chamber 14 is provided with its own tap hole 33. In normaloperation, the tap holes 32 and 33 are closed with plugs in the' usual manner. In the event that it is not desired to fractionate the metal condensate, the partition 16 may be provided with openings beneath the molten metal level in the chambers 13 and 14, thereby providing free communication for molten metal between these two chambers.

In operation, the condenser of the invention is preferably supplied with a. substantially continuous stream of metalliczinc vapor derived from the reduction in the vertical retort 5 of an agglomerated charge of mixed Zinciferous and carbonaceous materials. The gaseous product of theA reducing operation passes from the retort 5 through the orifice The gases flow and .down the tower 30 into the chamber 14. From the chamber 14 the exhaust gases, consisting principally of' carbon monoxide, escape through the tower 31 and burn at the top outlet thereof;A If desired, these exhaust gases may be appropriately collected for subsequent utilzation.

The metallic zinc vapor condenses to moltenv zinc metal on the walls of the chamber 13 and "ofthe vertical tower 25, and the molten metal accumulates in the sump or bottom of the chamber. Similarly, metallic zinc vapor is condensed to molten zinc metal and collected in the chamber 14. The molten zinc metal i condensingon the walls of the vertical towers runs down these walls into the chamber communicating therewith. By maintaining the chambers 13 and 14 at diiferent temperatures, fractional condensation of cadmium, and similar volatile metals, accompanying the gaseous product of the reducing operation may be obtained. Thus, the chamber 14 and its communicating tower 30 is maintained at a relatively lower temperature than the chamber 13 and its tower 25. The metal collecting in theI chamber 13 is then relatively high rade, containing substantially no cadmium.

n the other hand, the temperature of the chamber 14 is so regulated and controlled as to condense substantially all of the remaining zinc with such cadmium as comes off from the reducing charge. Thus, the zinc metal condensed and collected in the chamber 14 has a relatively high cadmium content. In this manner two grades of zinc metal, one substantially cadmium free and the other with arelatively high cadmium content, are condensed and collected by the improved condenser of the invention.

When metallic lead vapor is present in the gases coming from the reducing chamber, it will generally be condensed before the zinc and cadmium. The condenser may be provided With a sufficient number of liquid metal collecting chambers and condensing towers to provide for the recovery of several fractions. Thus, when the gases contain lead, zinc, and cadmium, the condenser may be so constructed as to provide for the recovery of two fractions containing relatively large quantities of lead and cadmium, and one fraction of high grade zinc metal.

I claim:

1. A condenser for metallic vapor comprising a plurality of liquid metal collecting chambers, a vapor inlet associated with one of said chambers, a gas outlet associated with the other of said chambers, two upright condensing towers respectively communicating with said chambers, a vapor passage eX- .tending between said towers adjacent the tops thereof, and means for maintaining said towers at different temperatures.

2. A condenser for metallic vapor compris- `ing a series of communicating condensing towers decreasing in volume from one end of the series to the'other in proportion to the decrease in volume of the gases as they flow through the condenser, a vapor inlet communicating with the interior of the first tower of the series, a gas outlet communicating with ,the last tower of the series, and means for separately collecting metal condensed in said towers.

3. A condenser for zinc vapor comprising a plurality of liquid zinc collecting chambers,

a vapor inlet associated with the first 1i uid zinc collecting chamber in the series,

I uprlght condenslng towers communicating with said chambers, a vapor passage extending between said condensing towers adjacent the tops thereof, a gas outlet associated with the last zinc collecting chamber, and means for re latin the temperature of said collectmg cham rs and condensing towers including. metal casings which are respectively space from the towers and which may be variably filled with a suitable heat-insulating material which may be regulated in amount in order to regulate the temperature.

In testimony whereof I affix my signature.

EARL H. BUNCE.

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