CA1069317A - Recovery of copper from chalcopyrite - Google Patents

Abstract

RECOVERY OF COPPER FROM CHALCOPYRITE

ABSTRACT
Chalcopyrite is converted to ferrous chloride and insoluble copper sulfides comprising covellite and chalcocite by reacting the chalcopyrite with cupric chloride and/or cuprous chloride at a temperature of at least about 110°C for sufficient time in order to convert substantially all of the reacted chalcopyrite to copper sulfides. Copper may then be conventionally recovered from the copper sulfides. In a preferred embodiment the Chalcopyrite to be treated is in the presence of one or more metal impurities, selected from the group consisting of lead, bismuth and zinc, as these metal impurities will be solubilized and thereby separated from the solid copper sulfides.

Description

BRCKGROUND OF r~HE INVENTION
__ _ Field of the Invention This invention deals generally with the hydrometal-lurgical recovery of copper from chalcopyrite, and particularly with the hydrometallurgical recovery of copper from chalcopyrite by means of a cupric and/or cuprous chloride reaction at part-icular processing conditions.

Prior Art Processes have long been disclosed describing the recovery of copper from its sulfide and mixed sulfide forms.
Most of the economic copper recovery processes are classified as pyrometallurigical, wherein the ore is smelted resulting in the oxidization of the sulfide sulfur to sulfur dioxide. This sulfur dioxide is of course now recognized '~ .

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as a major air pollutant, and means must thcreEorc be used in conncction with pyrometallurgical plants to eliminate - this contaminant. As a result considerable development is now being undertaken to formulate hydrometallugrical processes in order to circumvent the production of the by~product sulfur dioxide. Much of the hydrometallurgical development centers around ferric chloride and ammoniacal leaching processes, some of which may prove to ultimately be beneficial.
Elydrometallurgical processes to produce copper from chalcopyrite employing ferric chloride leach reactions - are known in the prior art. U.S. Patent No. 3,785,944 to Atwood discloses a process for xecovering metallic copper from chalcopyrite by leaching the chalcopyrite with ferric ` chloride to produce cupric chloride, reducing a portion of - 15 the cupric chloride to cuprous chloride by reacting it ~7ith fresh chalcopyrite feed, reducing the remaining cupric chloride to cuprous chloride with metallic copper, reducing the cuprous chloride to metallic copper by means of electrolysis and conventionally regenerating the ferric chloride leach reagent and removing the impurities. Similarly, U.S. Patent No, 3,798,026 to Milner discloses the production of copper from chalcopyrite by leaching the chalcopyrite ~ith ferric chloride to produce a solution containing cuprous, cupric and ferrous chlorides, reducing the cupric ch~oride to cuprous chloride by means of elemental copper, crystallizing a portion of the cuprous chloride from the resulting leach solution and reducing this cuprous chloride by means of hydrogen reduction to elemental coppcr, and txeating the mother liquor from the crystallization step in order to produce cement copper, regenerate the leach re~gents, and .

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1'7 r~movc the variou~ impu~itie3.
Th~se ferric chloride leach processes basically ~mploy the following two reactions:
` 51) 4FeC13 + CuFeS2 ~ SFeC12 + CuC12 + 2S
~2) 3CuC12 + CuFeS2 - ~ 4CuCl + FeC12 + 2S
As is seen from these reactions, the initial erric chloride reaction with chalcopyrite produces cupric chloride, and this cupric chloride in turn reacts wi~h chalcopyrite to produce ~uprous chloride. It is well recognized that reaction t2) does not proceed to completion, and therefore the resulting solution contains cupric chloride as well as cuprous chloride. It is generally considered to be desirable in the prior art to reduce this cupric chloride to cuprous chloride, usually by means of elemental copperO
Furthermore, as reaction (1) shows, for each mole of chzlcopyrite leached four moles of ferric chloride must be consumed and ~ive mcles of ferrous chloride are produced.
This excesslve amount of ferrous chloride must then be circulated throughout the process, creating cuprous chloride washing problems should a crystallization step be employed, and generally requiring further processing for its removal and/or regeneration. Furthermore ~lhen ferric chloride is employed to directly leach chalcopyrite the numerous metal impurities existing with chalcopyrite are also solubilized. Copper produced from such a solution is relatively impure as it is difficult to recover the copper without simultaneously recovering some of of the metal impurities.

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lO~i~317 A~ is disclo3ed in the ~twood referencc, col. 7, llne 70, the temperature o leach rcaction number ~2) must be maintained 1ess than 107C. Atwood discloses tha~
above 107C a portion of the copper is lost from solution, , _., S precipitating as a stable copper sulfide. A substantial amou t of copper is however still solubilized, and the examples in ~ his TABLE IV verify this. His tests at 143C result in a ~ portion of the copper in the feed being precipitated while the remainder of the copper is solubili~ed. Since Atwood's process requires a maximum amount of copper in solution as a result of this reduction reaction, he limits his temperatures - to less than 107C.
~ On the other hand the process of this invention can - tolerate very little solubili~ation of copper. The amount of copper solubilized, for example, by Atwood at temperatures in excess of 107C would negate the effectiveness of this process. Ho~Jever, it h~s been discovered that by maintaining - ptrticular processing conditions, contrary to Atwood's disclosures, substantially all of the copper can be recovered as solid copper sulfides. Furthermore, the process of the present invention can employ cuprous chloride as a reactant as well as cupric chloride in order to convert chalcopyrite to copper sulfides. Heretofore no prior art reference disclossd any reaction between chalcopyrite and cuprous chloride, not - 25 even the leach reaction which is known to occur with cupric chloride. Hence the process of the present invention can effect a separation of the copper values in a chalcopyrite feed from many of the impurities existing in the feed, incluaing iron, by reacting either cupric or cuprous chloride with chalcopyrite under particular processing conditions :
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~n addit:;onal chalcc~pyrit~ leacll reclc~iol~ i.!, disclosed in the assigllee's U.S. Patent No. 3,957,602, issued May 18, 1976, wherein chalcopyrite is leached with a copp~r sulfate solu~ion in order to produce ~n insoluble coppex sulfide, an iron sulfate solution and sulfuric acid. While this process is advantageous in that the copper sulfides produced may be easily separated from the xesulting solution, problems are also inherent. The resulting sulfate solution does no~ possess the capability to solubilize impurities such as lead and bismuth, and these impurities therefore remain wi~h the copper sulfides.
This necessitates further treatment prior to the recovery of copper. Furthermore, about 16%.of the sulfide sulfur rather than being converted to elemental sulfur as in the ferric chloride leach reactions must be oxidized to sulfate sulfur, requiring an additional 8 electrons per molecule. This greatly increases the energy expense in order to operate the process.
- The process of the present invention provi~es a number cf advantages over these prior art process~s. ~ith re~pect to the copper sulfate leach systems the process of the invention when conducted in the presence of lead and bismuth produces an insoluble copper sulfide while solubilizing ~he lead and bismuth in the ferrous chloride solution.
25~ This permits an immediate elimination of these impurities prior to any further proceSsing of the solia copper sulfides.
Not only the processing of the impurities is facilitated bu~ also the production of copper in a more pure formO

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10~9;~ï7 Furthermore, the present invention pcrmits the ch~lcopyrite to be convertcd to cuprous chloride, a preferred intermediate to cupric systems from the standpoint of ultimately reco~ering copper. Additionally, the sulfide sulfur can be converted to elemental sulfur, thereby saving the energy re~uirements of further oxidation of the sulfur and avoiding the substantial disposal problems associated with sulfuric acid. Also - the copper sulfide products are primarily chalcocite and covellite, as opposed to copper sulfates' product of di~enite.
The process of the present invention also possesses a number of advantages over the ferric chloride le~ching processes. By initially converting the chalcopyri~e to chalcocite and covellite a grea~er variety of subs-quent processes may be selec.ed for the ultimate recovery of coppe-. Also when ferric chloride leaching is employed to treat the copper sul~id_ product the ferric chlorlde requirements are greatly reducea. This decreases the processing expense as well 2s facilitating the later washing and purification of the product stream. Also various impurities in the fe-d material are immediately separated from the copper values, -esulting in improved purification schemes as well as a pure- elemental copper product.

SUM~L~RY OF THE INVENTION
Copper is recovered from chalcopyrite by ~eans of a process wherein the chalcopyrite is reacted with cupric and/or cuprous chloride at a temperature of at least abou. 110C in order to produce solid copper sulfides, prim~rily chalcocite anc co~ellite, ~h~ and a ferrous chloride solution. In a prefer_ed ' ,~

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93i7 embodimcnt, copper is rccovered from a feed material of chalcopyrite in the presencc oE one or more metal impurities selccted from the group consisting of lead, bismuth and zinc by reacting the feed material with cuprous chloride and~or cupric chloride at a temperature of at least about 110C
to produce a solid copper sulfide an~ a ferrous chloride solution wlth the metal impurities dissolved therein.
The solid copper sulfide may then be easily separated from the solution and further processed in order to recover the copper values.

BRIEF DESCRIPTION OF THE DRAWING
The figure illustrates a flow diagram lrcorpor~ting the process of the present invention in combinaticn with a preferred means of recoveFing elemental copper.

DESCRIPTION OF THE PREFERRED EMBODIME~TS
The basic chemical reactions with ~hich this process is concerned are as follows:
~ 3) CuFeS2 + 2CuCl ~ FeC12 * CuS + Cu2S
(4) CuFeS2 + CuC12 ----------~ FeC12 + 2CuS
- Z0 The primary copper sulfide products of the reaction (1) are chalcocite and covellite, and the primary copper sulfide - product of reaction (2) is covellite. Other copper sulf-des are formed in minor amounts. Additionally, a ferrous - ~hloride solution is produced and this ferrous chloride ~ay be later oxidized to ferric chloride and utilized in the further treatment of the copper sulfides.
In addition to chalcopyrite the starting mater~als may contain other copper sulfides, such as chalcocite an~
covellite and also may contain sulfidcs of other retals.

' 1'7 For example, copper may bo rccovorecl from mix~d sulfides containin~ chalcopyrite and zinc sulfide accordin~ to reactions (3) and ~) since the zinc will react to produce zinc chloride, permittin~ the insoluble copper sulfides to be easily separated from the solution of æinc chlorides and ferrous chloride. Similarly, lead sulfides, bismuth sulfides and nickel sulfides would react in the same manner as the zinc sulfides to provide an expedi~ious means of separating the copper sulfides from the iron and other metal constituents of the feed. The process is therefore particularly adapta~le to recovering copper from the above set forth compositions.
Additionally, other metal impurities may also ~e present in the feed material. Examples of such metal impurities commonly existing in nature with chalcopyrite include silver, antimony and arsenic sulfides. The chemical reactions of the present invention will not completely solubilize these metal impurities but they may be treated in a later fashion and removed from the copper values.
The temperature of the reaction between chalcopyrite and the cuprous and cupric chlorides is critical to the formation of the copper sulfide products. The reaction temperature must be maintained greater than about 110C, is preferably maintained greater than about 130C, and is more preferably maintained greater than about 150C. The upper limitation on temperature is dictated simply by practical eonsiderations since in order to reach the necessary reaction temperature the system must be pressurized. Below the critical temperature of abo~t 110C the reactions either do not proceed at all or result in totally different products. As is well jre~

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,, YI;~17 known in the tempcra~ur~ ral~Je of about ~O~C to about 105C chalcopyrite does not react with cuprous chloride, and this is born~ out by the disclosures of both the Milner and Atwood patents. Furthermore, wi~hin the temperature rarlge of about 90C to aboùt 105C cupric chloride reacts with chalcopyrite to produce cuprous chloride,ferrous chloride and elemental sulfur. Again, this is well known, and disclo~ed in the Atwood and Milner patents. Hence, below this critical temperature a mixture of cuprous and cupric chlorides reacting with cha7copyrite would produce a solution of primarily ferrous chloride and cuprous chloride, with some cupric chloride, since chalcopyrite is not sufficiently active to reduce all of the cupric chloride. All of these copper products, however, are in solution. Above this critical temperature the copper values are converted to solid copper sulfides, which can readily be separated from the product solution containing many of the metal impurities and iron.
Since chalcopyrite reacts with cupric chloride below about 110C to produce cuprous chloride in solution, it is preferable when using cupric chloride as a reactant in some instances to preheat the reactants to at least about llO~C prior to bringing them in contact with each other.
This prevents initial solubilization of the copper prior to attaining the reaction temperatures necessary to produce only insoluble copper sulfides. Alternatively one reactant stream may be sufficiently overly preheated such that the temperature of the combined reactants upon mixing is at least about 110C. However, if the solution is not preheated and some jrc:mb: -: ~:
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10~ 17 leaching of the chalcopyrito occurs prior to reaching the necessary temperature for the copper sul~idc production reaction, the cuprous chloxide produced as a result of the leach will be available to convert additional chalcopyrite to copper sulfides upon reaching the minimum reaction temperature.
The reaction time is an important parameter ~rom the standpoint of effecting a substantially complete separation of the copper values from the soluble impurities. The reaction should preferably be carried on for a time sufficient to produce substantially all copper sulfides from the reacted chalcopyrite. "Substantially all" copper sulfides is herein intended to mean preferably at least about 90%, more preferably at least about 95% and most preferably at least about 98%
conversion of the reacted chalcopyrite copper to copper sulfides.
The time necessary to accomplish this result is inversely proportional to the temperature, the time decreasing with increasing temperature. For a reaction temperature of about 150C a reaction time of four hours is sufficient to accomplish at least about 98% conversion of chalcopyrite to copper sulfides.
Due to the fact that a cuprous chloride/cupric chloride solution boils at about 107C at atmospheric pressure it is necessary to conduct the chalcopyrite reaction under pressure in order to attain the necessary temperatures.
Pressures necessary to attain given temperatures are known to the art.

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:, The production of coppor sulfides from chalcopyrite can be accomplished whether the copper chloride reactant i9 all cuprous chloride, all cupric chloride or a mixture of these two chlorides. When the reaction mixture is primarily cuprous chloride, the copper sulfide products tend to exist as covellite and chaloc~te, whereas when ~
the reaction mixture is primarily cupric chloride the copper sulfide product is primarily covellite. Therefore, as used herein the term "copper chlorides" is intended to mean either all cuprous chloride, all cupric chloride or any mixture-of cuprous chloride and cupric chloride.
The concentration of the copper in solution as copper chlorides is not particulaEly important, as long as it is sufficient to carry out the reaction. Therefore, the concentration is preferably maintained from about one gram per liter of copper to saturation concentration, more preferably from about 10 to about 150 grams per liter and most preferably from about 20 to about 100 grams per liter.
The amount of chalcopyrite required to react with the copper chloride solution is dictated by equations (3) and (4), One mole is required to react with two moles of cuprous chloride, while one mole of chalcopyrite is required to react with one mole of cupric chloride. Hence the stoichiometric amount of chalcopyrite required per mole of copper chloride solution is from 0.5 to 1.0 moles depending on the ratio of cuprous chloride to cupric chloride. In order to maximize the separation of the copper values from the resulting solution a slight excess of chalcopyrite is preferred.
Conversely an excess of copper chloride solution maximizes the amount of chalcopyrite converted to copper sulfides.

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, iO~9,~1'7 This chalcopyrite conversion rcaction may be periormed in more than one stage if desired and may be conducted cocurrently or countercurrently. ~lso as is common in hydrometallurgical processing, the raw feed material is preferably crushed and ground to a sufficiently fine particle size and concentrated, generally by means of flotation, prior to initiating the reaction.
Following the initial chalcopyrite reaction the copper sulfide product may be immediately separated from the solution containing the ferrous chloride and various metal impurities. Such a separation is accomplished by conventional means in the art, as for example by filtration.
Furthermore, depending upon the subsequent processing desired for the copper sulfide product, it may be advantageous in some instances to delay this separation until a later stage of the process.
Once the copper sulfide has been formed as a result ol the initial chalcopyrite reaction, further processing is employed in order to recover the copper values. One preferable technique is illustrated in the Figure. Generally the process illustrated in the Figure comprises feeding a suitable material to a reaction vessel wherein the chalcopyrite and various impurities are reacted with a copper chloride solution within the necessary processing parameters in order to form solid copper sulfides and a ferrous chloride solution containing man~ of the metal impurities. The solution is then filtered in order to separate the solid copper sulfides from the solution. The solution, which is substantially copper free, is then purified to recover the various metal impurities, ~rc:~

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leaving a ferrous clllorid~ soLu~ion. This fcrrous chloridesolution may be electrolyzed in ordcr to ~ccover iron at the cathode, while regenerating ferric chloride at the anode.
Alternatively, this ~errous chloride solution may be treated with oxygen to hydrolyze some ferrous chloride to iron oxide while oxidizing the remainder of the ferrous chloride to ferric chloride. The ferric chloride produced is then used in the leaching of the copper sulfides from the initial separation step. This ferric chloride leach is similar to a ferric chloride leach of chalcopyrite, producing elemental sulfur and a solution comprising cuprous chloride, cupric chloride, ferrous chloride, along with any metal impurities which were not solubilized in the initial reaction and which are solublilized in th~ ferric chloride leach reaction. This resulting solution may then be processed for the recovery of copper by reducing the cuprous and/or cupric chlorides to elemental copper. The remainder of the solution is then recycled to the initial chalcopyrite reaction in order to treat additional chalcopyrite feed material.
The general processing scheme disclosed in the figure possesses a number of alternatives, some of which are hereinafter described. Also other processes, such as those disclosed in U.S. Patents 3,798,026 to Milner and U.S. 3,785,944 to Atwood, could be employed to treat the copper sulfides.
These processes would necessarily have to be modified in certain respects since that the amount of ferric chloride required for the leaching phase is greatly reduced and the handling of the impurities is simplified. However, these and . - 13 -jxc: ~i~, -.

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.'. '' lV~91;~17 any othcr necessaxy modifications would be readily understood by thosc skilled in the ar~. Additionally, the leach phase of the process may ~e conducted in accordance with the processing discussion set forth by Dutrizac, Ferric S Ion as a Leaching Medium, ~lineral Science Engineering, Vol. 6, No. 2, April, 1974.
A preferable leaching technique involves a three stage countercurrent reaction utilizing ferric chloride and cupric chloride as the leaching agents. This leach process is perhaps best understood by first considering the thira stage.
This third stage receives heavily depleted copper sulfides from the second stage and ferric chloride. ~he ferric chloride is obtained hy the regeneration of ferrous chloride in a later stage of the process. The primary chemical xeaction in this third stage, assuming the primary copper - sulfides being treated are covellite and chalcocite are:
(5) 4FeC13 + Cu2S ~ 4FeC12 + 2CuC12 + S
(6~ 2FeC13 + CuS ~ 2FeC12 + CuC12 + S
In order to insure the consu~mation of all of the copper sulfides a substantial excess of ferric chloride is employed at this stage. This excess ferric chloride will react with any cuprous chloride present to produce ferrous chloride and cupric chloride as follows:
~7) FeC13 f CuCl FeC12 + CUC12 25- The tails are then separated from the solution and discarded. This third stage leach solution, containing ferric chloride, ferrous chloride and cupric chloride is then introduced into the second stage.

11)f~931~7 The second stage rec~ivcs partially depleted copper sulfides from the first stage and the third stage leac:~
solution. Additionally, regenerated ferric chloride and/or cupric chloride may be added at this stage. ~gain the primary reactions in this second stage are:
(8) 2FeC13 + CuS 3 2FeC12 + CuC12 ~ 2S

(9) 4FeC13 ~ Cu2S 7 4FeC12 + 2CuC12 + S
These reactions are conducted such that essentiall~
all of the ferric chloride is conver.ed to ferrous chloride. The cupric chloride present in the system in turn reacts with copper sulfide in order to produce cuprous chloride and ferrous chloride as follows:
~lo~ CuC12 ~ CuS ->2CuCl + S

(11) 2CuC12 + Cu2S ~4CuCl + S
Any remaining copper sulfide will be removed and sent to the third stage. The second stage leach solution therefore contains ferrous chloride, cupric c~:loride and cuprous chloride. The ratio of cuprous to cupric chloride depends upon the reaction conditions employed in the second stage leach.
The second stage leach solutfon, after having been separated from the remaining copper sulfide is then circulated to the first stage ~Jherein it is contacted with the fresh copper sulfide feed. The leach solution containing ferrous chloride, cuprous chloride, and cupric chloride reacts with the fresh copper sulfide feed according to the following reactions:
(12) 2CuC12 + Cu2S ~ 4CuCl + S
(13~ CuC12 + CuS -~ 2CuCl + S

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Again, all of tho cupric chlorlde is not converted to cuprous chloridc, as copper sulfido is not sufficiently activ~. Hence, the rcsulting leach solution from the first - sta~e contains cuprous chloride, ferrous chloride, and some cupric chloride. This solution is separated from the remainlng copper sulfides, and the copper sulfides are sent .o the second stage.
The cupric chloride in this solution may now, if desired, be reduced to cuprous chloride, preferably by means of elemental copper. This reduction may be by means known in the art, as for example, set forth in Milner. This reduc,ion step is however not required, and in many cases it is not desirable, as this cupric chloride may later be employed to reac~ with additional chalcopyrite feed material.
Preferably the leach solution is then cooled to crystallize a substantial portion of the cuprous chloride existing in the solution: Again, a crystallization as set forth in Milner is suitable. Preferably, the solution should be cooled to at least about 40C, more preferably to at least about 20C and most preferably to at least about 0~. .
The cuprous chloride crystals may then be separated from the mother liquor, this being accomplished by means known in the art, as for example, by filtration or centrifuging.
?5 The crystals are then washed to eliminate any solution impurities It is noteworthy that the ferrous chloride content of the solution prior to crystalliation is significantly lower than if the leaching step were performed on chalcopyrite, as much ..

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less ferric chloridc is rcquir~d to leach the copper sulfides.
Hence, this washing step is greatly facilitated. The crystals may be further purified, if necessary, by means known in the art.
The resultiny cuprous chloride crystals are of high purity, and may be reduced to substantially pure copper.
A number of techniques may be employed in order to effect this reduction. The cuprous chloride may be dissolved and the copper cemented from solution. Alternatively, it may be dissolved and recovered electrolytically by means known in the art. The preferable technique to be used in conjunction ~ith this process is to reduce the cuprous chloride by means of hydrogen reduction.
- The hydrogen reduction process may be carried out by various means krown in the art, as for example, those 15set forth in U.S. Patent ~o. 1,671,003, U.S. Patent No.
3,552,498, U.S. Patent ~;o. 2,538,201, U.S. Patent No. 3,321,303 and others.
Upon completion of the reduction of the cuprous chloride to elemental copper the elemental copper may be further treated by melting and casting in order to facilitate further handling. The by-product hydrogren chloride - - formed during the hydrogen reduction process may be later used in the regeneration stage.
The mother liquor from the crystallization stage comprises ferrous chloride, cupric chloride and some cuprous chloride, along ~ith various process impurities which were not solubilized by the initial chalcopyrite reaction.

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:. : : :: ' ~ ' ) 10~317 Prefcrably, at least about 20% o~ the cuprous chloride i9 remov~d in the crystallization step, more prefer~bly at least ~bout 35~ is re~noved, and most preferably at least about 50% i~ removed at this staye.
The mother liquor from the crystalIi~ation stage is then preferably preheated and introduced into the initial chalcopyrite reaction to permit the cupric chloride and cuprous chloride values of the mother liquor to react with additional chalcopyrite feed. Substantially all of the 10 cuprous chloride and cupric chloride are removed from the - mother liquor solution by adding a slight excess of chalcopyrite.
The solution from the chalcopyrite reaction with -the copper chlorides, com~rising ferrous chloride and the various metal impurities, may then be treated for the ~-removal of the impurities and the processing of the ferrous chloride. The impurities may conveniently be removed from solution by means known in the art, as for example, set forth by Allen and Kruesi in their article entitled "Cymet Electrometallurgical Processes for Treating Base Metal Sulfide Concentrates" presented at the Joint Meeting of the MMIJ-AIME in Tokyo,.May 24-27, 1972, print num~er T IV b 4. Once the impurities are removed, the solution comprises substantially pure ferrous chloride. This ferrous chloride may be treated by iron electrolysis in order to recover relatively pure iron at the cathode, while regenerating ferric chloride at the anode. Alternatively, a portio of the ferrous chloride may be processed by hydrolysis in order to regenerate ferric chloride and produce iron o~ide according to the following reactions:
~14) 4FeC12 + 4HCl ~ oC 3 H2O
(15~ 12FeC12 + 3 2 2Fe2O3 + 8FeC13 , .: ,' ,'.: :

-110~317 The reyenerated ferric chloride may then be recycled to the copper sulfide leach stage in order to treat incoming copper sulfides.
Alternatively, other processing techniques may be employed to treat the copper sulfides which are prdduced by the copper chloride reaction with chalcopyrite~ For example, the process disclosed in U.S. Patent No. 3,642,435 describing an oxygen leach would be suitable. Additionally the hydro-metallurgical process of U.S. Patent No. 3,736,238 1.~ could be employed. Also, if desired the copper sulfides may be treated by known pyrometallurgical techniques in order to recover the copper.

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10~;~317 F.X~MPLES
The following examples illustrate the reaction of chalcopyrite with cuprous chloride, cupric chloride and various mixtures of these two chlorides in the presence of vari~us metal impurities. The chalcopyrite feed material for examples 1-5 had the following composition: total copper: 25.98%;
iron: 27.3%; sulfur: 30.3%; lead: 0.036%; zinc: 0.143%; silver 0.009~; antimony: 0.04~; bismuth: 0.017~; and arsenic: 0.014%.
The mineral form of the copper was about 80% chalcopyrite, with L0 the remaining copper being attributed to other copper sulfides such as covellite and chalcocite. The reaction mixtures of each example were heated to 150C, and this temperature was maintained for the time period designated.
Example I
~he feed material was reacted with a solution comprising 150 g./l. iron as ferrous chloride and 60 g./l. copper as cuprous chloride. The total amounts of initial elemental values in grams include: Cu: 82.02; Fe 129.43; Pb: 1.04; and Zn: 1.23.
The reaction time was four hours. The results, tabulated as the amount of each product in solution versus the amount of the respective product in solid form are as follows:
.
Solution (g.) Solids (g.) Cu 2.62 79.~0 Fe 81.14 48.29 Pb 1.02 0.02 Zn 1.15 0.08 , - ~0 -~rC ~

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lO~g3~7 Example II
The copper chloride solution comprised 150 g./l. iron as ferrous chloride and 60 g./l. copper as cupric chloride providing total amounts of starting values in grams as follows: Cu: 79.30;
Fe: 122.95; P~: 1.00; and Zn: 1.17. The reaction was carried out for four hours with the following results:

_ Solution (g.) Solids (g.) Cu 0.01 79~29 Fe 91.17 31.78 Pb 0.93 0.07 Zn 1.14 0.03 Example III
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The solution composition for this test comprised 150g./1. iron as ferrous chloride; 30 g./l. cop~er as cupric chloride and 30 g./l.copper as cuprous chloride and total amounts of starting matPrials in grams of 78.63 Cu; 127.08 Fe; 1.06 Pb;
and 1.24 Zn. The reaction again was carried out for four hours with the following results:

:
Solution (g.) Solids (g.) - Cu 0,01 78.62 -Fe 93.21 33.87 Pb 1.00 0.06 Zn 1.20 0.04 Example IV
For this example the initial copper chloride solution comprised 150 g./l. iron as ferrous chloride, 60 g~/l. copper as cuprous chloride and 30 g~/l. copper as cupric chloride. The ~, .. .
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total amounts of starting values in grams included 96.97 Cu;
130.54 Fe; 1.01 Pb; and 1.28Zn. For a four hour reaction t~ime the results are as follows:

Solution (g.) Solids (g.) .
Cu 0.01 96.96 Fe 99.70 30.84 Pb 0.98 0.03 Zn 1.23 0.05 Example V
10 The initial copper chloride solution comprised 150 g./l.
iron as ferrous chloride, 60.g./1. copper as cuprous chloride and 30 g./l. copper as cupric chloride. The amounts of initial starting materials in grams included: Cu: 103.31; Fe: 124.29;
Pb: 1.08; Zn: 1.15; Ag: 0.06; As: 0.08; Sb: 0.84, and Bi: 0.40.
For a reaction time of four hours the results were as follows:

Solution (g.) Solids (g.) .
Cu0 .35 102.96 Fe96.06 28.23 Pb 1.06 0.02 Zn 1.11 0.04 Ag 0.01 0.0$

As 0.01 0.07 Sb 0.05 0.79 Bi 0.34 0.06 -- 2~ --. . ; ;,, :' - :, - . ;

lC~31'7 Example VI
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This test reacted 64.8 g. of chalcopyrite with a solution comprising 150 g./l. iron as ferrous chloride and 60 g./l.
copper as cupric chloride at 150C for 30 minutes, providing an initial amount of copper of 44.96 g and total initial iron of 91.20 g. The copper and iron results were as follows:

Solution (g.) Solids (g.) Cu 15.48 2g.48 Fe 83.62 7.58 The results of example VI show that even in a 30 minute time period a substantial portion of the copper in solution was reacted and removed from solution.
The copper sulfides produced in all of these examples were analyzed by X-ray diffraction and were proven to be primarily covellite and chalcocite. The test results indicate almost complete conversion of chalcopyrite copper to solid copper sulfides, while placing much of the chalcopyrite iron in solution as well as almost all of the lead, bismuth and zinc present.

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Claims (11)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for hydrometallurgically recovering elemental copper from chalcopyrite comprising:
(a) reacting the chalcopyrite with a copper chloride solution at a temperature of at least about 110°C. for sufficient time to convert substantially all of the reacted chalcopyrite to insoluble copper sulfides and a ferrous chloride solution;
(b) separating the copper sulfides from the ferrous chloride solution; and (c) recovering the elemental copper from the copper sulfides.

2. A process for hydrometallurgically recovering elemental copper from a feed material comprising chalcopyrite and at least one metal sulfide impurity selected from the group consisting of lead sulfide, zinc sulfide, and bismuth sulfide comprising:
(a) reacting the feed material with at least one metal chloride selected from the group consisting of cuprous chloride and cupric chloride at a temperature of at least about 110°C. to form insoluble copper sulfides and a solution comprising ferrous chloride and the metal impurities;
(b) separating the copper sulfide from the solution;
and (c) recovering the elemental copper from the sulfide.

3. The process of Claim 1 wherein the initial concentration of the copper chloride solution is from about 20 to about 100 grams per liter of copper.

4. The process of Claim 1 wherein the copper chloride is cuprous chloride.

5. The process of Claim 1 wherein the copper chloride is cupric chloride.

6. A process for hydrometallurgically recovering elemental copper from chalcopyrite in the presence of metal impurities comprising:
(a) reacting the chalcopyrite with at least one copper chloride selected from the group consisting of cuprous chloride and cupric chloride at a temperature of at least about 110°C
in order to form an insoluble copper sulfide and a ferrous chloride solution;
(b) separating the solid copper sulfide from the solution;
(c) leaching the copper sulfide with a ferric chloride solution in order to produce a solution comprising cuprous chloride, cupric chloride and ferrous chloride;
(d) crystallizing a substantial portion of the cuprous chloride from the solution of step (c);
(e) recovering elemental copper from the crystallized cuprous chloride;
(f) introducing the crystallized mother liquor from step (d) to the initial chalcopyrite reaction;
(g) treating the solution of step (a) in order to recover the metal impurities leaving a ferrous chloride solution;
and (h) hydrolizing the ferrous chloride solution to produce ferric chloride.

7. The process of Claim 6 wherein the chalcopyrite is reacted for sufficient time to convert substantially all of the reacted chalcopyrite to insoluble copper sulfides and a ferrous chloride solution.

8. The process of Claim 6 wherein the copper chloride is cuprous chloride.

9. The process of Claim 6 wherein the copper chloride is cupric chloride.

10. The process of Claim 6 wherein the initial concentration of the copper chloride solution is from about 20 to about 60 grams per liter of copper.

11. A process for hydrometallurgically recovering elemental copper from chalcopyrite comprising:
(a) preheating a copper chloride solution to a temperature of at least about 110°C.;
(b) preheating the chalcopyrite feed material to a temperature of at least about 110°C;
(c) reacting the preheated chalcopyrite with the preheated copper chloride solution at a temperature maintained at least about 110°C. to produce insoluble copper sulfides and a ferrous chloride solution;
(d) separating the copper sulfides from the ferrous chloride solution; and (e) recovering the elemental copper from the copper sulfides.