Floatation beneficiation method and copper recovery method

Abstract

To provide a flotation method that can effectively separate an arsenic mineral from a copper mineral.SOLUTION: The method includes an arsenic flotation step of subjecting, to flotation, slurry in which mineral ores including a copper mineral and an arsenic mineral are mixed without adding a collector or with a collector added thereto in an amount of 10 g or less per 1 ton of the mineral ores to give a floating ore including the arsenic mineral and a tailing ore including the copper mineral.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This specification discloses technologies related to a flotation method and a method for recovering copper.

Background Art

[0002] For copper ores containing arsenic minerals, various conditions for roasting and wet treatment for separating arsenic have been studied. However, these roasting and wet treatments are targeted at concentrated ores after a certain amount of unnecessary minerals have already been removed, and it is desired to be able to remove arsenic minerals by flotation at an earlier stage.

[0003] Regarding separating arsenic minerals by flotation, for example, Non-Patent Documents 1 and 2 have the following descriptions.

[0004] Non-Patent Document 1 describes that under reducing conditions where the oxidation-reduction potential (vs SHE) is -125 mV, with a pH of 11, chalcocite, etc. are preferentially floated, and then, at pH 11, the potential is raised to 0 mV to float enargite, etc., and then, by mixing these floating products and raising the potential to 290 mV or more, only enargite is floated. Also, this Non-Patent Document 1 describes that a bulk copper concentrate is recovered by flotation under normal conditions, and after re-grinding this, while using nitrogen gas, the pH is raised to 12 and the potential is set to about -150 mV to perform flotation, whereby a copper concentrate with a high arsenic content can be obtained, etc.

[0005] Non-Patent Document 2 describes that by performing flotation with a particle size of 10 μm after grinding, arsenic minerals are separated from copper minerals.

Prior Art Documents

Non-Patent Documents

[0006]

Non-Patent Document 1

[0007] All of the examples described in Non-Patent Documents 1 and 2 have limited conditions, and the technology for separating arsenic minerals from arsenic-free copper minerals by controlling such potentials and by granulation has not been put into practical use.

[0008] This specification discloses a flotation method capable of effectively separating arsenic minerals from arsenic-free copper minerals and a method for recovering copper. [Means for Solving the Problems]

[0009] The flotation method disclosed in this specification is to perform flotation with a slurry in which ores containing copper minerals and arsenic minerals are mixed to be alkaline, and without adding a collector to the slurry or by adding a collector in an amount of 10 g or less per ton of the ore, thereby suppressing the floating of the copper minerals, and obtaining, by flotation, a floating ore containing the arsenic minerals and a tail ore containing the copper minerals, an arsenic flotation step And, after the arsenic flotation process, a flotation process is performed on the slurry mixed with the tailings to float copper minerals in the tailings, and a copper flotation process which includes.

[0010] The copper recovery method disclosed in this specification is to recover copper contained in the floated ore obtained in the arsenic flotation process from the floated ore obtained by the above flotation method, where the floated ore contains copper minerals.

Advantages of the Invention

[0011] According to the above-mentioned flotation method, arsenic minerals and copper minerals can be effectively separated.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the invention disclosed in this specification will be described in detail. The flotation method of one embodiment includes an arsenic flotation step of performing flotation on a slurry in which ores containing copper minerals and arsenic minerals are mixed to obtain a floated ore and a tailing. In this arsenic flotation step, no collector is added to the above slurry, or the collector is added in an amount of 10 g or less per 1 ton of the ore. As a result, most of the arsenic minerals such as enargite, which are more likely to float than copper minerals such as chalcopyrite, are contained in the floated ore. On the other hand, copper minerals such as chalcopyrite will be contained in the tailing. As a result, arsenic minerals and copper minerals can be effectively separated.

[0014] The flotation method of this embodiment can be applied to a process as shown in FIG. 1, for example. In FIG. 1, for the tailing obtained in the arsenic flotation step, a copper flotation step is performed to float and recover the copper minerals contained in the tailing by flotation. Further, it is preferable to perform a copper recovery step of recovering copper from the floated ore obtained in the arsenic flotation step. Specifically, it is as described below.

[0015] (Ore) The ore is obtained, for example, by crushing the mined ore mined from a predetermined mine and then grinding it to a predetermined size. Among such ores, in this embodiment, ores containing copper minerals and arsenic minerals are targeted.

[0016] As long as it is an ore containing copper minerals and arsenic minerals, the specific minerals contained therein are not particularly limited. For example, it can include at least one sulfide mineral selected from chalcocite, bornite, covellite, chalcopyrite, pyrite, enargite, löllingite, and cuprite, and sulfide minerals containing gold and silver.

[0017] Particularly here, it is preferable to target ores in which the ratio of arsenic content to copper content (As / Cu) is 0.01 to 0.20 on a mass basis. For example, arsenic may be contained in the ore at 0.01% to 1.00% by mass, and copper at 0.1% to 10.0% by mass.

[0018] The average particle size D80 of the ore to be subjected to the arsenic flotation process described later can be, for example, 50 μm to 300 μm, typically 50 μm to 200 μm. By making the ore such a particle size through crushing, grinding, etc., when the addition amount of the collector is reduced in the arsenic flotation process as described later, the arsenic minerals to be separated may be more likely to float.

[0019] (Arsenic flotation process) In the arsenic flotation process, the ore as described above is mixed with a liquid such as water or lime water to form a slurry, and this slurry is added to a flotation cell. Thereafter, a foaming agent and other chemicals for forming froth are added to the flotation cell. In some cases, a depressant for suppressing the flotation of other minerals is added. When a pH adjuster is added to achieve a predetermined pH, air is supplied as an introduced gas, or air is supplied in a self-supplying manner, and the skimmer is rotated to recover the froth. The recovery of the froth may also be carried out by allowing it to overflow naturally from the flotation cell. Also, various chemicals added to the flotation cell may be added when made into a slurry.

[0020] In such flotation, in this embodiment, a collector for floating only the desired minerals is not added to the slurry, or even if the collector is added, the addition amount is 10 g or less per ton of ore (that is, 10 g / ton or less). In this case, arsenic minerals such as arsenic copper ore that are easily floated in the ore mixed in the slurry float up together with the froth. On the other hand, copper minerals that do not contain arsenic, such as chalcopyrite in the ore, precipitate without floating due to the fact that no collector or only a small amount of collector is added. Thereby, the arsenic minerals and copper minerals in the ore can be effectively separated.

[0021] When adding a collector, the addition amount shall be 10 g / ton or less. If the addition amount of the collector exceeds 10 g / ton, a relatively large amount of the collector will cause copper minerals to float up, and the arsenic minerals and copper minerals cannot be separated. From such a perspective, it is preferable that the addition amount of the collector is 5 g / ton or less, and further, no addition is made.

[0022] The collector is a kind of ore dressing agent. It adheres to the surface of minerals that cannot float under normal conditions, selectively imparts hydrophobicity to the surface, and is used for the purpose of adhering to the surface of the froth. The collector is generally often prepared by reacting various alcohols and carbon dioxide with sodium hydroxide or potassium hydroxide. Examples of collectors include xanthate-type collectors containing ethyl xanthate, dithiophosphate-type collectors, thiocarbamate-type collectors, etc., which have a collecting power especially for copper sulfide minerals and arsenic minerals. Typically, it is a xanthate-type collector, and specific examples thereof include PAX (Potassium Amyl Xanthate), PEX (Potassium Ethyl Xanthate), etc.

[0023] Also, when performing flotation in the arsenic flotation process, it is preferable to increase the pH of the slurry to a certain extent to make the slurry alkaline by adding a pH adjuster into the slurry as necessary in advance. By increasing the pH to a certain extent, the surface states of arsenic minerals and copper minerals and the bonding force with the collector change, and the separability between arsenic minerals and copper minerals can be obtained. The pH of the slurry can be, for example, 9 - 13, more preferably 12 - 13.

[0024] In the arsenic flotation process, the pulp density of the slurry can be, for example, 10% - 40%. The pulp density means the ratio of the ore (dry weight (g)) to the weight (g) of the slurry.

[0025] By going through the arsenic flotation process, a floating ore containing arsenic minerals and a tailing containing copper minerals can be obtained. However, the floating ore may further contain copper minerals, and the tailing may further contain arsenic minerals. It is preferable that the separation efficiency between arsenic minerals and copper minerals in the floating ore is 30% or more. For example, when 90% of arsenic minerals are recovered from the ore to the floating ore on a mass basis, it is preferable that the recovery amount of copper minerals is 60% or less. In the arsenic flotation process, it is preferable that 80% or more of arsenic minerals are recovered to the floating ore on a mass basis.

[0026] (Copper flotation process) The tailings obtained in the arsenic flotation process described above contain a certain amount of copper minerals, but may also contain other minerals that do not contain copper, such as quartz. In the copper flotation process, a slurry mixed with the tailings is prepared for flotation separation, floating the copper minerals in such tailings and separating and recovering them from other minerals.

[0027] In the copper flotation process, the collector described above is added at a rate of preferably 20 g to 200 g, more preferably 20 g to 100 g, and even more preferably 50 g to 100 g per ton of tailings. This is to effectively float the copper minerals in the tailings. If the addition amount of the collector is too small, there is a concern that the recovery rate of copper minerals will decrease. On the other hand, if the addition amount of the collector is too large, there is a risk that arsenic minerals in the tailings will also easily float.

[0028] In the copper flotation process, as a condition other than the addition amount of the collector, the addition amount of the frother can be increased, for example, about twice that in the arsenic flotation process described above. Also, the pH in the copper flotation process does not need to be as high as in the arsenic flotation process. For other conditions, flotation separation can be carried out under substantially the same conditions as in the arsenic flotation process. Note that after the copper flotation process, further flotation separation as a further concentration may be performed on the concentrate obtained by the flotation separation in the copper flotation process.

[0029] (Copper recovery process) The concentrate obtained in the arsenic flotation process described above contains a relatively large amount of arsenic minerals, but may also contain copper minerals. In order to recover the copper minerals in such concentrate, a copper recovery process can be carried out.

[0030] The copper recovery process recovers copper from the concentrate by a known method. For example, it is preferable to perform a treatment of leaching the copper in the concentrate into a leaching solution under predetermined high temperature and high pressure conditions in an autoclave. Alternatively, other treatments such as sulfidation may be performed to recover copper.

Example

[0031] Next, the flotation method as described above was experimentally carried out to confirm its effect, and the explanation is as follows. However, the explanation here is for illustrative purposes only and is not intended to be limited thereto.

[0032] (Test Example 1) Copper ore with an ore particle size in the range of 20 μm to 35 μm was prepared by grinding. The As content of this copper ore was 0.13% by mass, the Cu content was 3.5% by mass, and the Fe content was 1.0%. Using the slurry obtained by mixing the above copper ore with water, flotation was carried out for each of the case where PAX was added as a collector (PAX: 0 g / ton, Example 1-1) and the case where 100 g / ton of PAX was added (PAX: 100 g / ton, Comparative Example 1-1). In both cases, 100 g / ton of MIBC was added as a foaming agent.

[0033] The results are shown in Figure 2. Here, for the sake of convenience, assuming that all minerals containing arsenic are derived from chalcopyrite and all other copper minerals are chalcopyrite, the recovery rate is calculated. As can be seen from Figure 2, in Example 1-1, the recovery rate of enargite was 99% and the recovery rate of chalcopyrite was 60% in 15 minutes of flotation, and enargite could be preferentially recovered as floating ore. On the other hand, in Comparative Example 1-1, the recovery rates of both minerals were over 90%, and enargite could not be separated.

[0034] (Test Example 2) Copper ore with the ore particle size after grinding adjusted to 45 μm to 75 μm was prepared. The contents of As, Cu, and Fe of this copper ore are shown in Table 1. As Example 2-1, flotation was carried out on the slurry containing the above copper ore without adding a collector. At this time, 100 g / ton of MIBC was added as a foaming agent. As a result, the recovery rate of enargite in 15 minutes of flotation was 47% and the recovery rate of chalcopyrite was 10%, and enargite could be preferentially recovered.

[0035] As Example 2-2, flotation was carried out under the same conditions as above, except that 5 g / ton of PAX was added as a collector. As a result, the recovery rate of covellite was 81% and that of chalcopyrite was 37%, and a higher separability with a difference in the recovery rates of the two minerals of 44% was confirmed. Subsequently, NaHS was added, but no improvement in separability was confirmed. On the other hand, as Comparative Example 2-1, when flotation was carried out under the same conditions as above, except that 100 g / ton of PEX was added as a collector, separability could not be confirmed.

[0036]

Table 1

[0037] (Test Example 3) For each of the floated ores obtained from the flotation in the above Examples 1-1, 2-1, and 2-2, in order to recover copper from the floated ore, the floated ore was subjected to pressure leaching at 1 MPa under the conditions of a temperature of 180 °C, a pulp density of 100 g / L, and a stirring speed of 750 rpm in distilled water containing 0.34 mol / L of NaCl. As a result, copper could be recovered at a high recovery rate of 90% or more from any of the floated ores, while arsenic could be precipitated as a leaching residue to obtain a low recovery rate of 10% or less.

Claims

1. A flotation process is carried out on a slurry mixed with ores containing copper minerals and arsenic minerals by making the slurry alkaline, without adding a collector to the slurry or by adding the collector in an amount of 10 g or less per ton of the ore, so as to suppress the floating of the copper minerals, and by the flotation process, an arsenic concentrate containing the arsenic minerals and a tailing containing the copper minerals are obtained; an arsenic flotation step After the arsenic flotation step, a flotation process is carried out on the slurry mixed with the tailing to float the copper minerals in the tailing; a copper flotation step A flotation method comprising the above steps.

2. The flotation method according to Claim 1, wherein the ore used has a ratio of arsenic content to copper content of 0.01 to 0.20 on a mass basis.

3. The flotation method according to Claim 1 or 2, wherein in the copper flotation step, the addition amount of the collector is 20 g to 100 g per ton of the tailing.

4. The flotation method according to any one of Claims 1 to 3, wherein the arsenic concentrate obtained in the arsenic flotation step further contains copper minerals.

5. The flotation method according to Claim 4, wherein the separation efficiency between the arsenic minerals and the copper minerals in the arsenic concentrate obtained in the arsenic flotation step is 30% or more, and the separation efficiency is obtained by subtracting the recovery rate of the copper minerals from the recovery rate of the arsenic minerals.

6. A method for recovering copper, which comprises recovering copper contained in the arsenic concentrate obtained in the arsenic flotation step of the flotation method according to Claim 4 or 5.

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