BE630047A - - Google Patents

Description

       

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  Process and apparatus for the extraction of zinc From its undercut and oxidized crimp
The present invention relates to improvements in metallurgical methods and apparatus, and in particular to a new and improved pyrometallurgical method and apparatus for the extraction of zinc. from ores, oxides and residues and for the production of copper and zinc alloys *
According to the methods usually in use for the extraction of zinp from minorais of the blende type,

   the blende is first concentrated and then roasted in order to convert the cultures into oxides. The zinc is then extracted either by pyrometallurgy or electrochemically. Pyrometallurgical processes are processes either by Iota or by continuous distillation. All

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   Pyrometallurgical processes, however, rely on the same basic chemical reaction whereby carbon is reacted with oxide (zinc, with the addition of heat, which gives vapors of zinc and gaseous carbon oxide.

   Salon le * procedai! Usually, in the batch distillation process, the mixture of roasted minorais and charcoal is poured into a large number of clayey ceramic crucibles which are heated from the outside to determine the chemical reaction * These crucibles are made of a poor conductive material of heat and therefore they are inherently fragile.

   Consequently, they are small in size and a large number of such holes are required to treat large tonnages of zinc. One installation is cited where 11,000 crucibles of this type are used simultaneously Each crucible lasts about forty days *, and about a crucible and a third are needed for each tonne of zinc produced The distillation condensers are also made of clayey ceramic and about 159 are broken each day,

   The breakage of all these ceramic items was such an important aspect that groin distillation plants find it convenient to have a special section, the pottery, for the sole purpose of making the ceramic equipment items and so never running out of oreusets and condensers
It is clear that the use of such fragile equipment in the conventional batch distillation process makes this process expensive and cumbersome. In addition, due to the poor thermal conductivity of the crucibles,

     due to the endothermic nature of the overall reaction and the long time required for this reaction (24 to 48 hours), the fuel consumption is high under these conditions, rather than installing dis-

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   parentage in the vicinity of consumer markets or ore deposits, the location of this factories is fixed on the basis of the presence of inexpensive fuel resources.



   In both pyrometallurgical processes, namely batch distillation or continuous distillation, the condensation of the zinc vapors poses a very serious oxidation problem. Zinc vapors produced. have mixed with at least an equal volume of carbon oxides, still accompanied by carbon dioxide and dust, Carbon dioxide reacts with zine vapor to form very fine particles of zinc dioxide.

   This very fine powder of zinc oxide and the other fine dust present constitute germs on which the zinc vapor can condense to give fine droplets of zinc. The surface of this fine droplets is then oxidized by reaction with carbon dioxide which prevents the ooalesoen- oe of the droplets. This seriously affects the yield. In fact, as a result, in normal operation, approximately 2.3% of the zinc is lost in the gaseous effluent, and 20% of the zino actually distilled is found in the form of blue powder, a product essentially consisting of zino chips. oxidized on the surface.

   The blue powder must be redistilled to re-cut the pure metal.



   The present invention relates to a new process for the extraction of zino from these ores, as well as to an improved distillation apparatus for carrying out this process, said process and said apparatus eliminating, or at least reducing the drawbacks. listed above usual distillation procedures * More specifically, the method and apparatus according to the invention aim to simplify the extraction operations

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 zino from these ores, to eliminate the use
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 fragile o'ram1qUé crucibles,

   In order to reduce the specific consumption of fuel and to reduce the importance of the oxidation problems inherent in the usual procedures 49 OOl1danrat1on, the invention has additionally resulted in a unique new process for obtaining copper and zinc alloys from mine: i of zinc.



   According to the present invention, the novel process for extracting zino comprises the following steps
1. The zinc oxide concentrate is mixed with fine charcoal powder, the proportions by weight being such that one has one and two times the quantity of charcoal.
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 carbon theoretically necessary to reduce the oxide according to the following reaction;
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 Zoo + 0 Zn + CO
2. The mixture of zino oxide and charcoal powder is then poured into a molten copper bath or
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 of a7..ia "a of copper like brass.

   This mixture is submerged under the surface of the molten copper by a suitable device. The molten bath is maintained at a temperature
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 included omtru 1.000 and l 200 C for which the reaction proceeds quickly and the copper alloys immediately '
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 more reduced zinc. We let the irreducible matrix rise to the aur'taoe and we eliminate it,; 3.

   The alloy obtained is then ohau: f.'ké at atmospheric pressure or at a lower pressure, and most of the zinc evaporates under a neutral or reducing atmosphere; it is, condensed and recovered in mena * . The ouivre is then recovered and reused at the second duration of the cycle,

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 Other aspect.

   and advantage of the invention emerge from the more detailed description oi-aprea, la., which is made with reference to the accompanying drawings which illustrate an embodiment of a colon apparatus.
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 the invention being able to be used for the mine implementation thereof, intended in which,
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 The tiaure 1 had a vertical sectional view of a zino distillation apparatus according to the invention, certain
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 parts being assumed to be broken or being shown schematically for convenience of illustration) X3ure 2 seen and cut along line 2-2 of Figure 1;

     Figure 3 is a partial cross-sectional view.
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 corresponding to that of figure z, the plunger being raised in position 'olip.6e and the conveyor via pouring the mixture of zinc oxide and carbon into the bath of copper in ion; finally
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 Figure 4 is a partial sectional view corresponding to that of Figure 5 and showing the operation of removing gangue or supernatant residue from the surface of molten copper.



   If we now refer in detail to the following
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 Thus, and more particularly in FIG. 19, it will be noted that the distillation apparatus comprises a melting crucible 10 comprising a metal casing 12, the interior of which is
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 lined with a lining of xexuate bricks, lrea 14 of zircons or magnesia or any other similar substance, lined on its internal face by a layer 15 of bricks of silicon carbide or dancing graphite.

   The melting crucible 10 is surrounded by a heating device 16 which can be constituted by an induction coil or also by a resistance heating coil, or even by

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 any other suitable heating device making it possible to melt copper 18 and maintain this copper in the molten state.
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  The oyouoot do fusion 10 communicates with 14 upper part 20 of the oondonsour and it is connected to this part
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 by a tight seal 22 which prevents the air from entering but which allows toutetfoiu to dismantle the crucible and to separate it from the rest of the apparatus when cala is desired.



   The upper part 20 of the condenser comprises a vottioal section 24 and a horizontal section 26. The
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 upper part 20 of the coil has an outer steel shell 28 lined internally with a lining of insulating bricks 30, which are in turn lined with a row of graphite bricks 32. The
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  horizontal action 26 of the condenser su is in Clornmun1oat1on with the oblique part 34 of the condenser which is directed towards
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 the bottom, which * and consists of a casing or cast iron shell 36 coated with 38 year briqueu, Staph1tl 'gives.

   The role of the graphite bricks is to reduce any oarbonic gas that might form in the mine by carrying out the prood-
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 or any oxycin which could enter the interior of the device due to possible leaks.



  The first part 34 of the condonnour is attached to the upper part 20 of the condenser by a flange 40 and f) 1113 ends with a zinc accumulation pot 42 to which it is fixed by another flange 44. The zino collector pot has an interior lining of graphite 46 bricks, and is designed to collect zino in
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 metsae in metallic form in 48, as a result of the distillation process.

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   A screw conveyor 50 is mounted on the vertical section 24 of the upper part 20 of the condenser., And it is in communication with the interior thereof in order to bring the mixture of zinc oxide and carbon into the condenser. the melting crucible 10.

   A hopper 52 opens into the conveyor and is designed to deliver measured amounts of the above mixture. Via 54 of conveyor 50 can be engaged inside the upper section 20 of the condenser (or pulled back) by view of admitting at the desired moment the mixture supplied by the hopper 52 inside the apparatus. In the case of figure 1 the via 54 is withdrawn into its duct, while in the case of figure 3 it advances inside the upper part of the condenser and drops the powder mixture 56 to the surface of the bath 18 of molten copper.



   A plunger 60 is slidably carried by the top wall of the horizontal section 26 of the condensate, such that said plunger can descend into the vertical section 24, and enter the crucible therein. fusion 10. The plunger 60 comprises a shaft 68 which carries two plates 64 and 66 at its lower part. The upper part of the shaft 62 is connected to appropriate drive members (not shown here) able to raise and lower said shaft 62 as well as to drive it in rotation.

   The plates 64 and 66, upper and inner reapeoti- emit, are both provided with a series of holes 68 (see figure 1) which are distributed evenly around the shaft 62. Further, the plate lower plunger 66 port several teeth 70 which are directed downwards and which agitate the molten bath when the plunger plate is lowered and rotated $

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 A removable pad 72 is placed in the. wall of
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 Crucible 10 Immediately above the level of the bath or drunk 18 content. datiu said crucible.

   As shown in Figure 4 the plug 72 can be removed when desired in order to unmask an opening 74 allowing aodination to the surface of the molten copper bath 18 from the outside of the chamber. 1 device. After the M41ange of mina. spoke and coal has been added to the bath of molten copper the buffer 72 can be removed and a rake 76 or other
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 suitable tool can be introduced through ltcI'11o '74t in the manner shown in figure 4, shim in order to postpone the aoo- nothing and other residues floating on the surface of the bath and to drain them through the opening 74 * at the bottom end of the Lower party of.

   condenser> 4 is an exhaust port 78 allows it to extract the incondonoableu gases and to which it was possible to connect an appropriate apparatus for putting us vacuum laying down the distillation process. One way valve
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 80 is mounted for the exhaust port 78 and allows the zinc to be distilled off at atmospheric pressure.



   As shown in Figure 1, the device
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 includes 6 # aloment uilo 82 which acts as a reservoir and allows to aouraulate Large quantities of mixture of ore and coal, and of Ion to pour as and when required in the hopper of feed 52 As well as the shown in figure 2, a certain
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 number of burners to ga 86 surround the lower part of the oondenaeur 34 and it * allows to heat * it and to maintain its temperature between the point 4a melting and the point of boiling of the groin.

   znoutret the lower part of the condenser can also include one -or more diapo-e 34 with water sprinkler in order to increase the temperature

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 do the outer envelope do rise z values for which said envelope aéait menao6e.



  After the usual steps of roasting and agglomeration the minorai is softened to pass the whole fentont (At 200 cent sieve: 0.1110. And it is mixed with the resident gold granulation charcoal with low 0und * 08 , in aoufra t in volatile matter * The whole #et Blot '1617, ùromont Jlo6rQ, in order to give pale seeds aproxit1vûm3n danu aga tiunis do 10 to 20 mesh ..



  It, eet u8 ::; i 110duible ci'o.bl; lo'OOffU 'the milanfio then of the oonoMaer uìn to obtain ar, proxil11At1vomont the granulation marl; z know entered 10 and 20 meshes, The have then d4ver "fi 'in the silo of emrnttgaoina ± 0 62 one sees to feed the hopper 52 and the oonvoyaur to via 50 from which it can dtte admitted to destination of the crucible.

   In the second stage of the pr00083UfJ, the zino oxyda have reduced to tino and this one has ifn <! Dj.mtefMnt involved in an alloy, 00 which ab: 1.is.IQ the 1) 1't'J U 010n of zino vapor in a hovel such that the pluo 11'.J.ndfJ part is retained in the alloy * Plua IIJ.l40111q, 'I]' 1W 1t Q (Jt, h IJ1,), [N tilm- icomplît ooame follows <we prepared a copper bath in tuuion, ooiwne indicated in 18 out the fiuro 1, and the shaft 62 of the plunger is raised in order to bring the platoals 64 ot 66 of the plunger well above the urtace of the copper bath ot auaai above ni. veal of the oonvoyclul 'at via 50.

   The screw conveyor is then pushed back inside the enclosure 1) 1; the screw 52 rotates so as to 45 even a predetermined quantity of mixture of ore and coal in the fuoion bath, this in the way shown in figure 3o The via conveyor is then brought back ori back and the shaft 62 of the plunger is so that the trays 64 and 66 submerge the mixture of mincirai and charcoal knot the '1, \ 1 "1: 0.00 of the bath of

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 molten copper, The plunger is rotated at tempo in order to promote the mixture, to promote the agglomeration of the powders, and to release the carbon monoxide supplied for the redoction of the oxidation do zino with the carbon of the carbon. . Lea Laz escape on the edge of trays 64 and 66 as well as through orifices a 68 pl'nt1qu1 "," in the said trays.

   They have been extracted by the orilloe from uClttt1e the par-
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 putting them forwards? to the steam power plant
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 or 1 * roasting installation and 4 'ugftorn6: uHc) n oh oee ga will be able to (tra utiliedo as auxiliary fuel * Most of the tino lbbred by the reaction would have unnecessarily been absorbed into the bath of molten drunk to form! 'a brass and this zinc is fixed4 we this form tinq dortujne part of the zinc have volatilized and ne de ge noua, vapor form has de tlno for DI) condense in zino metal11qurJ in oondeneel.i.1'II 26 and 34 ut 5tr fina- 1;

  3 = nt collected from an oolleotor 42. the reaction t3entionn <! O 01-deniuc is band on the fact that at 1.000 0 and at-doinu3 the carbon reacts Y & pi4 * even admitting the oxide 4w 1100 po4r to give zinc and do the oxide
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 of carbon, while at temperatures of up to 1.20000
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 the vapor pressure of the zinc in a 15th grade brass is relatively low. Ctuot as well as a brass at 1 'of heated zinc 4 1200 0 and stirred will allow only 1 & 49 to escape and zinc content in one hour, which will make it a brass at 12.7f de zino, at a timri6rature of 1.750 OCt it takes more than five hours of ohawifage with the atmospheric prenalon to lower the zinc content of the brass to 2. As the zinc content of the brass increases,
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 the vapor pressure of the zino obviously increases.

   This is
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 as well as a brass te de zino heated for one day 1 hour without stirring, at a temperature of 1.100 C, will leave> #

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 escape 29. of its zinc.



   In the process according to the invention, the bath of molten copper is therefore maintained at a temperature above 1000 ° C. and below 1.200 ° C. Under these conditions, the zino oxide and the carbon will react rapidly, giving zino which will form an alloy with the copper, and most of the zinc will be fixed in the alloy due to its low vapor pressure at the temperatures used.



   As a specific example of implementation of the process according to the invention, a mixture of zino ore and coal is immersed in a bath of molten copper which is at a temperature of 1.180 C at the start of the o - operation and the temperature of which drops to a value of 1.120 C at the end of the reaction period.

   Constant mixing quantities are introduced every five minutes for a period of forty five minutes and a waiting time of fifteen minutes is Interposed after the last charge. It turns out that under these conditions 85 zinc is found in a brass at 14.12 zinc, 5% of the zino introduced remains in oxidized form in the residue, and only 10% of the zino is collected in distilled form.



   Conversely, when efforts are made to obtain alloys containing a quantity of zinc considerably greater than 15%, a greater part of the zinc is distilled and the reaction time is increased. Thus, if a larger quantity of the mixture of ore and coal can be added to the bath of molten copper maintained at the starting temperature of 1'180 C, the reduction operation lasts 65 minutes. , after which the mixture is drained. In this way we obtain an alloy at 18.4 of

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 zinc which contains 54.2% of the zino introduced, while 20% of the zino goes into distillation and 25% remains in the oxide form.



   In the third step of the process according to the invention, the zino is distilled from the alloy and recovered in ingot. As has been pointed out above, one of the most difficult problems with zinc condensation results from the interactions between zino vapors, carbon monoxide and carbon dioxide.



  When zinc droplets condense, carbon dioxide tends to oxidize surfaces so that normal. mont 20% of the zino is found in the form of blue powder which must be taken up in the cycle Even if we neglect the oxidation by carbon dioxide, the condensation from dilution gas always presents some difficulty, so a t - showers or bubbling baths in liquid metal are proposed to condense the vapors, with additional showers to clean the vapors that have crossed the first doubts. Such expedients reduce the difficulty without eliminating the initial causes and represent a complication and an additional expense,
In the method according to the invention,

   it is pure zino which is evaporated, all the diluting and oxidizing gases being removed, which has the effect of reducing the production of blue powder to a very low value and allowing a process and a condensation apparatus which are both simple and economical. According to this process, after aohonnement of the reduction step, the plungers 64 and 66 are raised above the level of the screw conveyor 50 and the ore residue floating on the surface of the. molten copper are skimmed off and removed through opening 74, as shown in Figure 4.

   A vacuum pump

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 Wt then Íaoao14e to Ilotitioa dtiohappownt 76 and the tom posture of the molten copper is raised up to the value of 1 * 18000 in order to distill the zinc shells the weak
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 pressure provided by the vacuum pump. In this% conditions,
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 there is constant vaporluatien of zinc z the surface of the bath.



  The plates of the diver 64 ot 66 uont entrained in rotation and in reciprocating movement during the whole duration of the operation in order to keep constant the temperature and the oompoultlon you bath laying the diotillations Although not esalnt 1el1A,: rj Its very stirring action is useful as it ao061bl9 dilution. Pure zinc is easily aloymed and the production of blue powder is low enough to be regarded as negligible.

   This is how elu'on the occasion of an ess1, lfAl11ae having been maintained at the temperature of 101 ± 000 and stirred under reduced pressure, the zino content of the alloy was lowered from 1411 to 1 'to 292, e in sweet houroe, the metal being recovered forms us maa ivo. We give a few examples Illus. Trant d1l: rQntos ways of implementing in practice the above described above Example n I A roasted oonoentré containing 70% of zîno is mixed with pulverized charcoal, & lomr4 we forfao cylinders having about 25 of diameter then conousi
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 to give a granule passing through a 10 mesh sieve.

   AT
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 out <$ of zinc, the ore oonoentt6 contains the * elements 01-apebe or their oxides: 1ty, of strong 0 &%? of oa4miumt 0 | 0K "of cuprous oxide, 0 | O03: 'd t a1'8.n1o 0 0O08f" of e.nt1. moino, 0.01r of lead, 3, a of sulfur, O, 4r "of alumina, 2t4, r 'of silica, 2.6' of lime and 1.6 tf of magnesia and finally
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 13 grams of silver per tonne *

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 85 parts of mounted copper melted and maintained
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 initially z a temperature of 1.18O C the temperature of the bath being gradually lowered to ... 2? C the end of the reaction, the mixture of 1ner1 and charcoal is introduced in portions 63aloul de oin ;. minutes in five minutes, laying forty five minutes.

   We then wait fifteen minutes after the last introduction * The molten bath is
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 then poured and the obtained ingot were pink ot analyzed. We thus obtain 99 parts of a brass containing 14, yew of zino, 0.5 '' 'do soufra, and 0 O2f' before. No cadmium is present in the ingot, In the condenser, there are 1.6 parts of ssind to bzz "'of cadmium, The ingot was then remelted, its temperature
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 raised to 1180OCt the water pressure of the molten bath was abaiaeio, and the bath was stirred so that the lino evaporated and was oondenad, Thus was recovered z. parts of sine, leaving 87 parts of a 2.2% zino brass.

   
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 Example II 226 parts of drunk are melted which are maintained at 1.1800 ° u at the time of the start of the reduction, the temperature dropping pro5xd.varnant to 1120 ° at the end of the reduction. To this molten bath are added 92 parts of briquettes of zino oxide and charcoal, set in three batches at ten minute intervals. The mixture is poured twenty minutes after the addition of the last charge. On analysis it turns out that we get 269 parts
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 of a brass at 16.0? ' de came and 16 parts of a 1 ', Soidu to 60 de zino. 4.4 parts of zino are recovered in the condenser.



  In total 75.5 *. zinc are found in brass, 16.8; - 're & tent us unreduced oxide, and 7e5t' appa *. ralt as a pure metal diBtl1Á ..

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  The brass ingot is remelted and it is heated
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 at a temperature of 1,760oQ in a reducing atmosphere and maintained at oetta temperature for five hours. 86% of the zinc content is distilled and recovered in massive form while the residual bath comprises 232 parts of a brass
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 at 5;.' zinc.
It goes without saying that the initial charge of the crucible may be constituted * by waste brass and not
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 from top quality copper. In this case, one nom- rtieiiotrn by distilling the zino o contained in the brass and once we have a 2% brass it will be used in the second step of the process as a protective medium for
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 effootuar the initial reduction.



  It should be noted that instead of turning the ore residues from time to time during the reduction period, or also at the end of the reaction, and to proceed immediately to the distillation of the lino. we
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 could detach crucible 10 from junction 22 and drain the molten bath into a similar crucible to separate the residue from the alloy. Zinc distillation
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 could then be aooompliu in another apparatus of Ill'M1 kind, used only for this distillation * This apparatus could comprise a very small condenser cooled with water in order to condense the zino in massive form without a melting step.



   Instead of condensing zinc into solid metal
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 evaporating during the second stage, it is possible to fill the condenser from the humus with copper shavings so that the vapor and the droplets of zino
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 m3.year, ant with oe metal for gives? a brass. The temperature of the chips should be kept below the melting point of brass and below the melting point of zinc.

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 Once these shavings have retained a sufficient quantity of zinc, they could be added to the molten bath on the occasion of the third stage to recover the metallic zinc by distillation.



   Instead of lowering the pressure, the zinc contained in the alloy can be evaporated by slowly raising
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 the temperature after the reduction step, so that the zinc vapors which drive the carbon monoxide hora to the condenaur through the exhaust port 78. The ori-Z100 of ocupemont 78 is then closed by actuating valve 80 and the temperature of the bath was raised more quickly in order to have uninterrupted evaporation of the zinc.
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  The present invention is not limited otrictee ment to z.no ore, dtaut4eti substances which can be treated and oonvortiElI3 in m3t .. massive by the process according to the invention. This proo3db can in particular be used for trans: fo1lIn'J1 'in product of quality aup4r: l.oure of powder b5, ue, of zino powder, of lno oxyda and don d6ohots of zinc fortimont oxidized.



  Instead of ohoroher to get a massive pure zino
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 by fully operating the process d60rit previously, it is possible to stop the process at the end of the second step ot ohroher to take advantage of the brass obtained. This may be particularly desirable when the zino material present at the start consists essentially of only zino, zino oxide and copper and when the alloy constituting the initial molten bath is relatively pure.
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  After several successive cycles, appreciable amounts of precious metals such as gold and silver and impurities will accumulate in the copper constituting the bath. It will therefore be desirable to take some time off

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 to other copper and to refine it by the electrochemical processes in order to recover! * the precious metals * The pure copper can then be returned to the melting crucible or else
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 it can be sold as high quality copper ot rom. placed in the melting crucible by a relatively low cost brass to restart the prooeaoue.

   With regard to the impurities, it is clear that the lead content in the minorais should be low, since the oo "lead is fed both in the brass and in the distillate. sulfur should also be made ble given the tendency of sulfur to bind to drunk,
An essential aspect of the invention lies in
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 the ability of this process to be performed automatically.



  A liver that a correct procedure has been defined for a particular mineral, it is possible to operate colon a cy-
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 three-hour automatic goose during which the mixture of ore and coal is introduced into the copper in fu-
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 alon at Fixed intervals, the diver is trained. in its back and forth movement of rotation in the inter- valea dealemont re6btxrn:

  to the. têtipdraturs au ouivift is kept constant or brought ± 9 to vary according to a specified oyolo, the residue aat eliminated intorvalloe determined and finally the zinc is distilled. Once this cycle is completed, the next cycle can begin, the labor requirements are still modest. This allows
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 substantial savings in manufacturing.



   Further savings resulting from the relatively modest process requirements for heat input
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 Once the copper has warmed up to the desired temperature, the amounts of additional heat are small and t:

  - correspond 26ux quantities n6oeus .-. iros to reduce the oxide

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 of zinc, to evaporate the zinc, to compensate for the heat doors of the bath by radiation and to heat the gangue
The size of the apparatus according to the invention is also modoate, having regard to the large quantities of materials which it makes it possible to treat, it as well as current furnaces for operating the Iota distillation have a capacity of 0.06 m3 and may contain approximately 50 kg of a mixture of coal and ore to 70 ore containing 70,

   zinc. This means that these furnaces can contain around 400 kg of zinc per m3. If the. duration of a cycle - In such an oven this 24 hours, that. means that the hourly production of zinc is of the order of 16 kg per m3 of furnace Conversely, with the process according to the invention, the hourly production of zinc reaches 300 kg per m3 of capacity,

   
In order to determine whether it was possible to use metals other than copper in the process according to the invention and, if so, which metals would be suitable, a series of somble experiments was carried out at the This experiment is described in Example II, except that the temperature was maintained at 1180 ° C during the entire process.

   Copper, lead, acid, and aluminum were used to provide the metal reaction bath and all of the water was carried out under the same conditions. The table below shows the results of this series of experiments.

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  TABLE I
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 Zino'rdoupdré test A: test B: test C test D
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<tb> (Cu) <SEP> (Pb) <SEP> (Sn) <SEP> (Al)
<tb>
 
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 in alloy 94 3 3tl + 5 22.4
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<tb>: <SEP>: <SEP>: <SEP>
<tb>
 
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 by distillation 5 ,,, -: '23.9? : 16.87 '19 sc,: under, forma d a-: Os4; ". 73. 7th: 51.65'.
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<tb> xyde <SEP>: <SEP>:
<tb>
 
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 In Test D, where aluminum was used and a very appreciable percentage of aluminum was transformed into aluminum oxide.
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  On the basis of closed results oi-deI3s; ';. a, it can be concluded that the use of copper is essential in the process according to the invention for: Ltcbt-3ntion of the high rate; of oonvsr- sion..A'oxide zinc zino contained in the alloy ,, and that lead, tin and aluminum can not, it is practical, be used within the framework of the process according to the invention.
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  M3ma prooédij wing and the apparatus according to the invention have been described on 80 referring to partial examples book of realization, it goes without saying that many mvdi: t1- ouations, omialiliol1s and auonotionp can be operated oas exemplos without for as much to leave the cadra do. the invention * RESUMA 1.

   This metallurgical process for flouring
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 minorais and zinc oxides is developed by creating an intimate mixture of materials based on zinc oxide.
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 zinc with a quantity of oarbonv, at least sufficient. to reduce the totalized of the oxide of zino, oe mixing being
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 ensuito ohauii6 by total immoralon under the surface of a liquid bath cQns4-tu, esoontiollement of molten copper, oe liquido bath eliant ipaintionu indirectly at a temperature between l.pOO ot 1.200 C for ten minutes 4tu,

  = Itln

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 so that the carbon can reduce the zino oxide to metallic zino and that the zino thus obtained constitutes with the drunk a brass containing up to 16% of zino, said reduction reaction and the formation of said brass having completely lost or below the surface of said molten copper bath.



   2. The brass bath is heated to a compressed temperature between 1.180 and 1.760 C in order to evaporate the zino or contained in the brass, then to condense and recover the zino thus evaporated.



   3. A closed enclosure coated with carbon is used to prevent oxidation of the recovered zino.



   4. The second heating stage is carried out under a pressure lower than atmospheric pressure.
5. Zino oxide nozzle material is prepared by roasting a minorai do zino.



   6. The metal bath at a temperature of 1000 to 1200 C is stirred.



   7. The mixture of zino oxide and carbon is obtained by creaking and agglomerating an ore containing zino in order to essentially convert all of the contained zino into zino oxide, the product obtained is crushed into a fine powder, by adding finely pulverized charcoal, and by running the mixture so that it skates with tarais, from ten to twenty mallas .. '
8.

     The metallurgical apparatus for the refining of ores ot oxides of zino by the above process includes a melting hole for copper, organs suitable for heating the crucible with a view to melting the copper, an oondensour which is connected to the 'a back ends of said melting crucible and which communicates with it, a collecting chamber for the reception of the metallic zino which was connected to the other end of the aforesaid condenser'

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 and 'which is in communication with it, means for introducing the mixture of zinc minorai and carbon into' '' said condenser above the melting crucible,

   so that said mixture falls into the bath of molten drunk contained in said melting crucible, means for immersing said mixture, on the surface of said bath of molten drunk, and also for agitating the said mixture. bath and the mixture thus immersed in the heated crucible.



   9. A screw conveyor introduces dosed quantities of the mixture of ore and coal, and devices allow the crucible to be heated at all temperatures including around 900 and 1900 C.



   10. A port and valve are in communication with the end of the condenser which is near the collecting chamber for the metal sine, and are capable of being connected to a vacuum generating apparatus during operation. distillation of the zinc, with a view to evaporating the latter at the crucible level and recovering it in the collecting chamber.



   11. A plunger is mounted inside the condenser or lower inside the crucible to immerse the mixture on the surface of the molten water bath.



   12. Lo plunger comprises a plate comprising several orifices for the passage of gases.



   13. The plunger comprises a shaft which carries the plate and which is capable of carrying out rotational movements ot back and forth. '
14. The plunger plate has a number of teeth for agitating the molten copper bath when the plunger plate is lowered into said copper bath and the shaft is rotated.

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  1 $, A metallurgical process where extroire was refined 1..inc contained in the powder bl u da zinc and the waste of tine tai que ai.d88U! ' spoU'U-