DE2441342A1 - HYDROMETALLURGICAL PROCEDURE - Google Patents

Description

The invention relates to a new hydrometallurgical process for treating copper concentrates for extraction of copper contained therein. In particular, the invention is concerned with a method for the extraction of copper by Leaching of copper concentrates in an aqueous leaching solution at elevated temperature and under excess oxygen pressure. .

There are already hydrometallurgical methods of treatment of copper concentrates in aqueous sulfuric acid leaching solutions known at elevated temperatures and under an oxygen pressure, when carrying out the copper in the Leach solution is dissolved and then pulled out of the solution by electrical means or the like.

^509813/0780 -

Such a method is described in CA-PS 712,989. In carrying out this process, the mineral sulfides are leached using a solution containing sulfuric acid in an amount at least sufficient to combine with the copper present in such mineral sulfides to form sulfates, whereupon the resulting slurry under a pressure of a free oxygen-containing "gas is reacted at a temperature above 80 ⁰ C (175 ° F).

Another method is described in CA-PS 808 108. In carrying out this process, the mineral sulfides, which have a particle size such that at least 90% pass through a 325 mesh sieve, are leached in an aqueous sulfuric acid solution under certain conditions which are such that the amount of acid is sufficient to stoichiometrically with it to combine the copper contained in the sulfides as sulfates, the amount at the same time being such that the molar ratio of acid: copper in the resulting slurry is below 1: 1, but above 0.55: 1. The reaction is carried out at a temperature between 99 and 121 ^C C (210 to 250 ⁰ F) under an oxygen partial pressure of more than 7 kg / cm ² , absolute (100 psig).

There are some significant disadvantages associated with these known methods. For example, the concentrate must be finely ground, furthermore, a substantial amount of an incompletely leached concentrate must be kept in circulation which is released from the leach outlet slurry must be separated by flotation, and finally is a rather long copper separation step required due to the fact that any dissolved iron must be reprecipitated from each leach solution. Consequently has none of these known processes have found their way into the industry on a broader scale, despite the fact that that a hydrometallurgical treatment of copper concentrates

50981 3/0780

is of considerable interest as they are all air polluting Avoids gases that are released during normal melting and conversion measures.

The object of the invention is to create a new and effective one hydrometallurgical process for the treatment of copper concentrates, When it is carried out, the disadvantages of the previously known acid leaching processes are avoided or largely eliminated will. The invention is intended to provide a hydrometallurgical process which the Excellent results can be obtained using an aqueous leach solution containing chloride or bromide ions contains, with the copper from the leachate and not from. the leach solution is extracted. Furthermore, a hydrometallurgical Processes are created that can be applied directly to copper concentrates in the state in which they arise, without the need for further grinding.

From the following description, go according to the invention achievable advantages.

The hydrometallurgical method of the invention for extraction of copper from copper concentrates consists of the following steps:

(a) Formation of an aqueous leach solution, the chloride or bromide ions contains in predetermined concentrations,

(b) dispersing copper concentrates in such a leach solution forming a slurry,

(c) performing the leaching at an elevated temperature as well under an excess of oxygen pressure in compliance with such chloride and bromide ion concentrations that a major part of the copper in the concentrates is converted into a solid basic copper sulfate,

• -

(d) Separating the obtained .Auslaugrückstandes, the basic Contains copper sulfate, from the leach solution, and

5098 13/0780

(e) Recovery of the copper from the leach residue.

The source of chloride or bromide ions in the aqueous leach solution can be sour or not sour. For example, HCl or HBr can be used to deliver such ions will. However, you can also use chlorides or bromides, such as sodium chloride, calcium chloride, ammonium chloride, Use sodium bromide, potassium bromide or the like in a satisfactory manner.

To form the aqueous leaching solution, the chlorides or the bromides or the hydrochloric acid or the Hydrobromic acid simply in water in a predetermined amount Concentration dissolved. The exact concentration can depend on many factors, such as the one used Source of chloride or bromide ions, the leaching temperature maintained as well as the applied oxygen pressure, the grinding of the Concentrate, if such milling is carried out, the leaching time, and the like. However, in all cases the concentration must be such that under the prevailing working conditions a major part of the copper in the concentrates is converted to an insoluble basic copper sulfate while maintaining satisfactory total copper conversion conditions will. Under the term "solid basic copper sulfate" it is to be understood that this basic copper sulfate is present in the leaching solution used to perform the leaching operation is solid and does not dissolve to any major extent in such a solution.

To achieve these results, the molar ratio Cl " or

Br ″ down to 0.08 , especially when HCl or Cu 1

HBr can be used as a source of chloride or bromide ions. Higher ratios are also suitable, with at one point a maximum effective concentration of Cl or Br is reached, whereby when this point is exceeded only a low one or no additional effect at all is achieved if the concentration is further increased.

50981 3/0780

In addition to the source of chloride or bromide ions, a source of sulfate ions, such as sulfuric acid, sodium sulfate or the like, can also be introduced _{into the leach solution. However, the introduction of SO 4} ions into the leach solution is not essential as the reaction will proceed even then if these ions are not added initially. _{It is assumed, however, that S0 4} ~~ ions are formed in situ during the leaching at elevated temperature and under an oxygen pressure and then take part in the conversion of the copper sulfides to basic sulfate.

In the most preferred embodiment, the leach solution is using a mixture of hydrochloric acid and sulfuric acid educated. If an acidic mixture such as this is used, then it is preferable to have the total amount of acid in the obtained slurry is such that the molar ratio

H is between about 0.15 and 0.65 , the molar ratio Cu_ 1 1

Cl in the slurry is greater than about 0.08 . Usually Cu 1

such a mixture contains at least 25 percent by weight of hydrogen chloride acid.

Regardless of whether an acidic leach solution is used initially or not, the pH of the leach solution usually stabilizes and remains after a certain reaction time between about 2.5 and 4.5 until the reaction is complete.

As regards the leaching temperature as well as the oxygen pressure, these parameters depend on many factors, for example those mentioned above. However, any combination which provides the desired result of converting a major portion of the copper contained in the concentrate to a solid basic copper sulfate and which permits the desired high total copper conversion is satisfactory. Temperatures between approximately 125 and 16O ⁰ C and in particular between 140 and 150 ⁰ C have

50981 3/0780

proved to be very suitable. Oxygen partial pressures above

2
one-half 12.6 kg / cm, absolute (180 psig) and especially between

2 2

14.0 kg / cm absolute and 21.0 kg / cm absolute (200 and 300 psig)

have proven to be very satisfactory.

The leaching is carried out in an autoclave with sufficient agitation, for example at 600 rpm, the leaching time being should be sufficient to effect a satisfactory overall conversion of the substrate contained in the copper will. The total conversion should be at least about 90% and preferably greater than 97%. Under the term "Total conversion" is intended to mean the total percentage of copper in the concentrate that is insoluble basic Sulphate is converted, which remains in the residue, also the soluble copper sulphate, which goes into solution. Typically, a period of about 2 1/2 hours has been found to be satisfactory for maximum overall conversion to achieve.

The copper concentrates which are treated according to the invention can, are the usual concentrates, which mineral sulfides contain, for example chalcopyrite, chalcocite, covellite, bornite or the like. Or mixtures thereof. The procedure is however particularly well suited for the hydrometallurgical treatment of chalcopyrite concentrates, which are the most common are in the industry.

A notable feature of the invention is that such a concentrate, in the form in which it is obtained, can be treated, i.e. without further grinding. Possibly however, the concentrates can be milled for a period of about 1/2 hour or so to make them slurried Form can be introduced into the autoclave and leached. However, care must be taken to ensure that there is no excessive grinding of the concentrates, since the percentage the dissolution of copper in the case of ground concentrates

50981 3/0780.

is greater than in the case of not milled, taking into account is that according to the invention the resolution is not above 50% and preferably not above 40% of the total converted copper should be because most of the copper is converted into an insoluble basic copper sulfate that remains in the residue. Therefore becomes a Grinding carried out, then you can adjust the other reaction conditions accordingly (for example, lowering temperature) in order to avoid excessive dissolution of copper.

Similar considerations apply when adjusting the solids content in the slurry. Usually is a percentage of solids between about 20 and 30 weight percent is sufficient. These are the percentages as they are normally be adhered to. Lower percentages are also satisfactory, but it should not be forgotten corresponding attitudes regarding the conditions,

H and Cl or Br as mentioned above, Cu Cu Cu

as well as regarding the temperature and the oxygen pressure, to avoid excessive dissolution of Cu in the leach solution.

As already mentioned above, the pH fluctuates of the slurry generally between about 2.5 and 4.5 as the reaction proceeds. It is believed that this is due to the establishment of an equilibrium during the reaction between the formation of copper sulfate and solid basic Copper sulfate is due according to the following equation:

3CuSO ₄ + 4H ₂ O CuSo ₄ -2 Cu (OH) ₂ + 2H ₂ SO ₄

soluble copper-solid basic sulphate sulphate

It should be noted, however, that this explanation is based only on an assumption and is not intended to restrict the invention,

5 09813/0780

The exact pH that is maintained can to some extent be controlled by other variables, for example by the temperature, the composition of the leaching solution, the nature of the concentrate, the percentage observed solids or the like. The conditions can be easily controlled by a hydrometallurgeon.

When the leaching is complete, the solid residue is separated from the leaching solution, for example by filtration, and washed to remove the remaining traces of chloride or bromide ions. This residue mainly contains iron, sulfur and basic copper sulphate. The presence of the basic copper sulfate in the residue could be determined by X-ray diffraction analysis. For example, the following composition was found: 20% S °, 35% Fe ₃ O ₃ , 36% CuSO.2 Cu (OH) ₂ and 9% remaining components including any precious metals present. There are some known methods by which the copper can be recovered from such a residue. For example, one can carry out a selective dissolution of copper in an ammoniacal ammonium sulfate solution and a subsequent solvent extraction of the ammoniacal liquid, a stripping with sulfuric acid and an electrical recovery from the sulfuric acid solution. The residue can also be leached in dilute sulfuric acid and then followed by a solution purification stage and electrical recovery from the purified solution obtained. Such methods are known. It is not necessary to describe them in more detail as they do not fall within the scope of the invention.

The filtrate obtained from such a separation contains essentially all of the chloride or bromide ions, some dissolved Cu in the form of CuSO ₄ and practically no iron. This filtrate can therefore be used again for subsequent leaching measures after making appropriate corrections. Therefore, the method according to the invention can either be char-

509813/0780

be carried out sequentially or continuously on a cyclic basis. The continuous procedure is particularly advantageous because it enables the leach solution to be used over and over again. Despite the fact that some Cu is dissolved in this solution, the concentration of this dissolved Cu will generally remain constant as the solution is recycled. Therefore, in this way, a steady and continuous extraction of copper is possible on the basis of the invention. It is much easier to recycle the liquid solution rather than the solid unreacted concentrates, as is done when performing some known hydrometallurgical processes.

The invention will be described with reference to the accompanying drawings explained in more detail. Show it:

1 shows a flow diagram of a preferred embodiment of the method according to the invention;

Figure 2 is a graph showing suitable molar ratios H_ reproduces in an acidic leach solution,

Cu that can be complied with according to the invention;

Figure 3 is a graph showing suitable molar ratios C_l reproduces in a leach solution that

Cu can be complied with according to the invention;

Figure 4 is a graph showing suitable amounts

in an HCl leaching solution on HCl / as well as on H "S0 *, which are used according to the invention

can be reproduced.

The simplicity of the method according to the invention is shown in FIG. emerged. As shown in this figure, a suitable one becomes

50981 3/0780

Leaching solution containing chloride or bromide ions is introduced into a vessel or into an autoclave 1 in which it is reacted with the copper concentrates at elevated temperature and under excess oxygen pressure. The liquid / solid separation is then carried out in unit 2. The solids are washed with wash water to remove residual traces of chloride and bromide ions, while the leaching solution can be returned to unit 1 and used for the next leaching operation.

The copper is removed from the residue in a known manner, as above set out, won.

For those cases where an acidic leach solution is prepared, Figure 2 illustrates the effect of acid concentration on copper conversion and distribution. In this particular case, an HCl / E ^ SC ^ leach solution containing 51.5% by weight HCl is used. The working temperature is 145 ° C. The partial pressure of oxygen is adjusted to 14 kg / cm ² , absolute (200 psig). The slurry contains 25 weight percent solids. The reaction time is 2 1/2 hours. It is clear from this graph that when one is seeking a relatively high percentage of total copper conversion while dissolving Cu in the leach solution of only about 30% or less, the molar ratio H_ between

Cn should be 0.15 and 0.65.

1 1

In Fig. 3 is shown that to achieve high overall conversion of copper and an approximately 30% Cu-dissolution in the presence of chloride ions, the molar ratio of Cl "is larger than should be 0.08. At approximately 0.1 ^u stabilize the loading

1 1

conditions, with a further increase in the Cl " ratio

Cu does not give improved results, but neither does one exerts an adverse influence. However, it is extremely surprising to find that in the absence of chloride ions, the percentage the total copper conversion is less than 40%, while

509813/0780

■ /

in the presence of only 0.08 moles of Cl "" per mole of present Copper this conversion increases to about 97%. The working conditions in this case are the same as

in the case of Fig. 2, the molar ratio H_ at 0.29

Cu 1 lies.

Fig. 4 shows that when an HCl / H-SO ^ combination is used, at least 25 wt .-% HCl are required to achieve the desired high total copper conversion and a low To achieve Cu dissolution. Again, conditions stabilize at some point, with another Increasing the amount of HCl does not give a particularly beneficial effect. The working conditions are the same as in accordance with Fig. 3.

The following examples illustrate the invention without restricting it.

Examples 1 to 20

In order to show the suitability of various sources of chloride ions and their combinations with one another or with sulphate ions, a series of tests is carried out in an autoclave using a gaspe copper concentrate in the resulting form, the solids content 25 %, the temperature 145 ° C , the pressure is 14.0 kg / cm ² , absolute O ₂ , the reaction time is 2 1/2 hours and the stirring speed is 600 rpm. The copper concentrate used in the resulting form has a particle size such that 72% by weight falls through a 325 mesh Tyler sieve (72% by weight minus 325 mesh), the concentrate containing chalcopyrite with a smaller amount of bornite. The results of these tests are summarized in Table I below:

509813/0780

Table I Composition of the leaching solution, gpl

Example NaCl
No.

HCl CaCl.

NH ₄ Cl

H ₂ SO ₄

Na ₂ SO ₄

yield

% Copper% acid soluble copper

wall distribution

lung Cu in the Cu in the

(total) residue solution

O
—J
OO

10
11
12th
13th
14th
15th
16

17 **
18th

19 *

20 *

27.2
5.5
2.8

13.6

27.2

8.5 -

34.3 -

24.9

17.0 -

17.0 -

17.0 14.5 -

16.1 -

10.45 -

34.0 -

68.0 -

27.5 -

13.5 -

0.5 -

0.5 -

16

19.45 5.45 16.0 32.0 64.0 25.8 1.33 1.00 5.0

23.2

46.4

75
67

82

78.0

66.9

9.8

79.8

85.3

73.3 85.4 26.1 38.5

96.6

96.0

97.4

98.7

94.3

97.4

97.6

97.5

99.3

97.0

99.2

39.20

96.75

98.7

99.1

95.4

98.9

96.20

63.9

69.4

97.6 37.6 41.0 62.2 87.8 95.0 63.5 79.8 75.0 73.4 68.8 24.3 71.2 59.2 25.6 0.0 57.2 66.5 4.2 7.0

2.4

62.4

■ 59.0

37.8

12.2

5.0 36.5 21, 2 25.0, 26.6 31, 2 75.7 28.8 40.8 74.4 100.0 42.8 33.5 95.8 93.0

* The tests are carried out at a temperature of 175 ^° C. and not at 145 ^° C. as in all other cases.

** The tests are carried out with a solids content of 35%

and not with a solids content of 25% as in all other cases carried out.

From the table above it can be seen that various chloride ion (Cl) sources either alone or with one another or can be used together with SO. ~ sources, for example sulfuric acid or sodium sulfate. However, if an insufficient chloride concentration is used as in the case of Examples 2, 3, 19 and 20, then does not achieve satisfactory results because the excess Cu goes into solution. Even if no chloride ions are used as is the case in Example 12 only achieved a total conversion of 3 9.20%. If too much acid is used, as in Examples 15 and 16, then too much copper dissolved, so that the inventive method becomes ineffective. The best results are obtained according to Examples 9 and 11, when carried out an overall conversion of over 99% is achieved, with also an acceptable Cu distribution in the residue and in the solution is detected. Other satisfactory results are those of Examples 1, 4, 5, 6, 8, 10, 13 and 18. More or less satisfactory results are obtained when Examples 7 and 14 are carried out.

Examples 21-25 (cyclic

A five-cycle pressure leach is carried out using a gaspe copper concentrate as it is, the concentrate being composed as follows: 24.4% Cu, 30.6% Fe and 32.5% S-Die selected Conditions are as follows: temperature: 145 ⁰ C; Pressure: 14 kg / cm ² , absolute oxygen (200 psig); Solid

509813/0780

content: 25%; Agitation: 600 rpm; Leach time: 2.5 hours; Initial solution composition: 17.0 gpl HCl and 16.0 gpl H ^ SO _{4 t} (molar ratio H ^ = 0.63). The leach solution from each previous cycle is used in performing the next leach cycle. The chloride ion concentration in the leach solution is maintained at the initial level during the addition of the hydrochloric acid. No sulfuric acid is added when performing the cyclic tests. The pH during each press leach stabilizes at 2.8-3.2. The results are summarized in Table II below.

Table II

lye solution

ttnwand- Aus

Leach residue leach solution% Cu% S

At-% by weight Cu Fe total S Cu SO. Fe,

Loading ⁴

21 118 24.9 26.3 26.4 18.2 12.3 none 98.0 78 22nd 135 20.0 22.7 23.9 11.5 7.0 Il 98.3 80 23 128 18.6 24.0 24.1 12.8 7.9 Il 98.9 79 24 131 19.6 23.4 23.4 10.6 7.1 Il 97.4 77 25th 130 18.8 23.6 24.4 12.1 9.0 Il 98.1 74

The values in this table show that during recycling no copper or sulphate accumulates in the solution, the copper and sulphate, which in the system after the reach the first cycle are quantitatively contained in the leach residue. The sulfur is in the residue as basic sulphate and elemental sulfur. The average yield of elemental sulfur is 78%. The average copper conversion is determined to be 98.2%. The results clearly show that any leaching can be carried out cyclically, with no adverse effect on the degree of copper conversion or the

50981 3/0780

Copper distribution is determined.

In addition to the above examples, the following effects are examined:

1. Effect of temperature '

The effect of temperature over the range of 115 to 1.75 ⁰ C. using a Gaspe-copper concentrate in the form as it is obtained (72% pass through a 325 mesh Tyler sieve), and using such a ground concentrate (99 % falls through a 325 mesh Tyler sieve) under an oxygen ^{pressure of 14.0 kg / cm 2} , absolute, with a solids content of 25%, with stirring at 600 rpm and during a 2.5 hour leach time, where the leaching solution contains 17.0 gpl HCl and 16.0 gpl H-SO. The results show that the copper conversion in the case of the concentrate that is processed as it is, is essentially independent of temperature in the range of about 145 to 175 ^° C., but with a slight decrease when the leaching occurs at 135 ⁰ C or below is carried out. The percentage of copper dissolution increases with temperature over the entire area. The best temperature range seems to be between 125 and 160 ° C. If the ground concentrate is converted, then lower temperatures also prove to be sufficient.

2. Effect of pressure

The effect of the oxygen partial pressure on the leaching is investigated using the same material and under the same conditions as those observed above in connection with the effect of the temperature. The results show that the preferred pressure range is between 14.0 and 21.0 kg / cm ² , absolute oxygen, however

509813/0780

slightly lower or slightly higher partial pressures can also be complied with. For example, oxygen pressures as low as 7.0 kg / cm ² , absolute, have proven successful in some cases.

3. Effect of time

The effect of time on copper conversion and distribution in the pressure leaching of Gaspe copper concentrate as received (72% will pass through a 325 mesh Tyler sieve through) is also examined. The conditions met are the same as those related above with the temperature and pressure effects have been complied with. The results show that the copper conversion increases rapidly with time, up to about 1.5 hours, and is essentially complete in 2.5 hours. The amount of dissolved copper is within the acceptable range of 30 to 40%.

4. Effect of percentage solids

The effect of the percentage of solids in the slurry of a Gaspe copper concentrate in the form, in which one it will be obtained is investigated. It will be found that a range of 15 to 35% is satisfactory provided that the molar ratio H_ in a corresponding manner

Cu is adjusted when the percentage of solids is up moved in the lower area. The copper conversion is 98% and the extent of copper dissolution is 43%. The preferred one Range is between about 20 and 30% solids.

5. Effect of milling - Examples 26-33

A series of experiments is carried out using a gaspe copper concentrate which is

50981 3/0780

for a span of 1/2 hour to determine whether the copper conversion can be increased. The results are summarized in Table III below.

50981 3/0780

Table III

example

No.

Composition of the leaching solution, gpl

NaCl

HcI

H ₂ SO ₄ leaching conditions % S total Cu time, temp. _{0 0} Yield ferumwand- ⁰ C kg / cm ² , 1

absolutely

·,% Back
was standing 99.9 86 99.6 96 99.6 57 99.9 73 99.8 51 99.6 90 98.5 99 96.8 96

% acid-soluble copper distribution solution

cn
σ
co
oo

26 27 28 29 30 31 32 33

27.2 - 5 • - 0 27.2 - - - 5 8th, 0 27.2 - - - 8th, 8th, 13.6 - - 27.2 - - 27.2 - -

2.5 1 45 1 4.0 64 2.5 1 30th 1 4.0 62 2.5 1 30th 1 4.0 69 2.5 1 45 7.0 63 2.5 1 30th 7.0 64 2.5 1 30th 1 4.0 70 1.5 1 30th 1 4.0 68 2.5 1 15th 1 4.0 64

14 3

27

2U1342

The values in this table show that leaching of the ground concentrate with 27.2 gpl NaCl over a period of 2.5 hours at 145 ° C or 130 ⁰ C under an oxygen pressure of 14.0 kg / cm ^2, a copper absolute conversion of more than 99.5% (cf. Examples 26 and 27). A reduction of the leaching of 2.5 to 1.5 hours at 130 ⁰ C constitutes copper conversion to 98.5% decrease. A reduction in the oxygen pressure from 14.0 kg / cm ² , absolute to 7.0 kg / cm ² , absolute when using a leaching with 27.2 gpl NaCl at 145 ° C. does not affect the copper conversion. The conversions that are achieved when leaching with 8.5 gpl HCl + 8.0 gpl H2SO ^ are identical to those obtained with 27.2 gpl NaCl, provided all other conditions are the same.

The copper distribution of the ground material leached absolutely with sodium chloride under an oxygen pressure of 14.0 kg / cm ² is similar to that obtained using the copper concentrate used as it is. A reduction in the oxygen ^{pressure to 7.0 kg / cm 2} , in absolute terms, greatly increases the copper dissolution. The proportion of copper that is then dissolved when the leaching is carried out with the HCl / HpSO. Solution is higher than when sodium chloride is used, as a result of the increased acidity of the system.

Example 34

To test the effectiveness of the bromide ion reactive activity under similar conditions, an autoclave test is performed using a Brenda copper concentrate as received. This copper concentrate contains 28.4% Cu, 26.1% Fe and 30.8% S. A combination of H2S0 ₄ and KBr is used. The following conditions are met: The slurry contains 25% solids and the

509813/0780

Leaching solution 16 gpl H ₃ SO ₄ and 57 gpl KBr. The temperature
is 145 ° C and the oxygen pressure 14.0 kg / cm ² , absolute.
The reaction is carried out with stirring at 630 rpm.
Oxygen is passed through at a rate of 3 l / min.

The results of this test are summarized in Table IV below:

% Copper
umwand
lung Table IV Fe (total) Leach solution Leachate
time, Wed
grooves 23.6 none , gpl pH 5 53.0 Composition of Il 3.3 10 63.6 Cu, gpl ■ 1 4.3 15th 86.7 4.0 It 4.7 30th 96.3 2.9 If 5.0 60 99.1 1.8 Il 3.8 90 99.2 0.8 Il 3.3 150 2.0 3.6 3.0 2.9

It can be seen from this table that the bromide ions react in the same way as the chloride ions, their presence leading to very high overall conversions after only 60 minutes of leaching time, meaning results similar to
can be achieved with the use of chloride ions.

Example 35

The test of Example 34 is repeated using as the initial leach solution the final filtrate of the test according to Example 34 is used. This filtrate is presented to approximately 57 gpl KBr brought into the autoclave for recycling, but none

509813/0780

fresh sulfuric acid is added.

The results of this test are shown in Table V below

summarized.

% Copper
conversion Table V Fe (total),
gpl pH Leaching time, 6.9 2.7 2.2 Minutes 9.1 2.8 1.8 5 26.3 Composition "of the leach solution none 3.3 10 71.9 Cu, gpl Il 3.9 15th 95.1 7.1 Il 5.0 30th 98.9 6.8 Il 3.4. 60 99.1 6.1 Il - 90 5.6 150 2.3 4.4 4.1

These results again show that the recycling of the leaching solution, with appropriate adjustment of the bromide ion concentration, leads to satisfactory results which are similar to the results obtained when using chloride ions. The chloride and bromide ions therefore react in essentially the same way. - = ·· - _; . ■

The possibility of using the other two halogen ions., ./. such an approach is also being investigated.

A test is carried out and when carried out a · ·. . \ Leaching solution is used which contains iodide ions. The desired results are not achieved. The Druckauslaiig-; Residue produced in this test - contains a large amount of unreacted concentrate and can be; very, badly ..: filter. The obvious failure of this. Solution is un-.

5 09813/0780,

waits, as it is known that a copper; (II) sulfate solution with Iodide ions with precipitation of copper (I) iodide and with release reacts to iodine.

A fluoride ion based leach solution is not practicable, since such solutions the. attack human skin and glass fixtures, and most likely react with the silicate gangue minerals in the copper concentrate. Therefore, the fluoride ions are a suitable reactant of those of the present invention To exclude considerations.

Thus, only chloride and bromide ions, or a combination thereof, are for the purposes of the hydrometallurgical of the present invention Suitable for treating copper concentrates.

The above non-limiting examples and results clearly show the simplicity and the degree of efficiency as well as the advantages of the new method according to the invention, which makes a significant contribution to the hydrometallurgical extraction of copper from copper concentrates.

509 813/07 8 0

Claims (21)

Claims 1. Hydrometallurgical process for the extraction of copper from Copper concentrates, characterized in that (a) An aqueous leach solution is formed which contains chloride or bromide ions at a predetermined concentration contains, (b) Forming copper concentrates in this leach solution dispersed in a slurry, (c) leaching this slurry at an increased Temperature and under an oxygen pressure as well as under Compliance with such a concentration of chloride or bromide ions is carried out that the main amount the copper present in the concentrates is converted into a solid basic copper sulphate, (d) the leach residue obtained, which is the basic copper sulfate contains, is separated from the leach solution, and (e) the copper is recovered from the leachate. 2. The method according to claim 1, characterized in that the aqueous leaching solution used, which contains chloride ions, is formed using hydrochloric acid. 3. The method according to claim 1, characterized in that the aqueous leaching solution containing chloride ions is formed using NaCl, CaCl or NH.C1. 4. The method according to claim 1, characterized in that the aqueous leaching solution used, which contains bromide ions, is formed using HBr, NaBr or KBr. 5098 13/07 8 0 5. The method according to claim 1, characterized in that the
used aqueous leaching solution containing chloride ions,
using a mixture of hydrochloric acid and
Sulfuric acid is formed, the mixture at least
Contains 25 wt% hydrochloric acid. 6. The method according to claims 1, 2, 3 or 4, characterized in that the aqueous leaching solution used also
contains a source of sulfate ions. 7. The method according to claims 1, 2, 3 or 4, characterized in that the observed molar ratio Cl or Br " Cu Cu in the slurry is greater than about 0.08 . 8. The method according to claim 2 or 5, characterized in that the total amount of acid in the slurry is adjusted in this way is that the molar ratio H_ between approximately 0.15 and 0.65 . ^Cu 1 1 9. The method according to claims 1, 2, 3 or 4, characterized in that that the pH of the slurry is maintained between about 2.5 and 4.5 during the leaching reaction. 10. The method according to claims 1, 2, 3 or 4, characterized in that the leaching is carried out at a temperature between about 125 and 160 ⁰ C. 11. The method according to claims 1, 2, 3 or 4, characterized in that the leaching under an oxygen partial pressure between approximately 14.0 and 21.0 kg / cm ² , absolute (200 and 300
psig). 12. The method according to claims 1, 2, 3 or 4, characterized in that the leaching takes place during such a period
is carried out, which is sufficient to at least 97% 509813/0780 To achieve overall conversion of Cu. 13. The method according to claims 1, 2, 3 or 4, characterized in that that the copper concentrates used consist essentially of chalcopyrite concentrates. 14. The method according to claims 1, 2, 3 or 4, characterized in that that the copper concentrates used in the leaching solution in the state in which they arise, without prior Grind to be dispersed. 15. The method according to claims 1, 2, 3 or 4, characterized in that the copper concentrates for a period of time
1/2 hour before dispersing in the leach solution
to be married. 16. The method according to claims 1, 2, 3 or 4, characterized in that that after the leaching residue has been separated off, this residue is used to remove residual traces of chloride or Bromide ions is washed. _ 17. The method according to claims -1, 2, 3 or 4, characterized in that after the separation of the leach residue
remaining leaching solution recycled and again under
Formation of an aqueous leach solution is used which is suitable for treating fresh copper concentrates on a continuous cyclic basis. 18. The method according to claims 1, 2, 3 or 4, characterized in that the leaching is controlled in such a way that
no more than about 40% of the converted copper goes into solution with the remainder precipitating in the residue as solid basic copper sulfate. - 509813/07 8 0 19. The method according to claims 1, 2, 3 or 4, characterized in that that the copper from the residue by selective dissolution of copper in an ammoniacal copper sulfate solution and subsequent solvent extraction of the ammoniacal liquid, stripping with sulfuric acid and recovery is obtained electrically from the sulfuric acid solution. 20. The method according to claims 1, 2, 3 or 4, characterized in that that the copper from the residue by leaching the same in dilute sulfuric acid and a subsequent Solution purification stage and extraction is obtained by electrical means from the purified solution obtained. 21. The method according to claim 1, characterized in that (a) Forming an aqueous acidic leach solution containing chloride or Contains bromide ions, (b) copper concentrates are dispersed in this leach solution to form a slurry, (c) the total amount of acid in the slurry is adjusted such that a molar ratio H_ between about 0.15 and 0.65 is obtained, ^Cu 1 1 (d) the amount of chloride ions in the slurry such it is set that the molar ratio C_l or B_r is greater than 0.08 , ^{Cu Cu} (e) leaching at a temperature between about 125 and 160 ⁰ C is carried out under an oxygen partial ^{pressure of more than 12.6 kg / cm 2} , absolute (180 psig) while stirring the slurry, (f) the leach residue obtained, which is essentially the copper in the form of basic copper sulfate, is separated from the leach solution, and (g) the copper is recovered from the leach residue. 5098 13/0780 Blank page