WO2017081802A1 - Method for separating molybdenum, and method for processing copper-containing molybdenite - Google Patents

Abstract

This method for separating molybdenum separates molybdenum from an acid solution containing copper ions, ferrous ions, and molybdenum ions, wherein ferrous ions in the acid solution are oxidized and the pH of the acid solution is adjusted to 0.5 to 3.0, whereby at least a portion of the ferrous ions are precipitated as a ferrous compound and the molybdenum ions in the acid solution are precipitated as a solid to separate the molybdenum.

Description

Method for separating molybdenum and method for treating copper-containing molybdenum ore

The present invention relates to a method for separating molybdenum from an acidic solution containing copper ions, iron ions and molybdenum ions, and a method for treating molybdenum ore containing copper, and in particular, leaching a raw material containing copper and molybdenum. The present invention proposes a technique that can contribute to an improvement in the recovery rate of molybdenum in separating and recovering molybdenum from an acidic solution obtained by doing so.

Molybdenum is added to stainless steel, structural alloy steel, high-strength steel, alloy tool steel, cast forged steel, superalloy, etc. in the steel and special steel fields, and is used as a catalyst, chemicals and leather dyes in the chemical field. May be. In addition, molybdenum may be processed into a form of molybdenum wire, machined product, or assembly part in the metal field, or may be used as a processed product for a magnetron part, a semiconductor part, an electron tube part, or the like.
In recent years, from the viewpoint of effective use of resources, when various metals are collected from such raw materials as used electronic parts, molybdenum may be contained in the acidic solution in which the scraps of the electronic parts are leached. Therefore, it is desired to effectively separate and recover this molybdenum.

Molybdenite is molybdenite (MoS ₂ ) (molybdenum sulfide), molybdenum lead ore (wulfenite, PbMoO ₄ ) (lead molybdate), pawerite (Ca (Mo, W) O ₄ ), iron-water lead ore (Fe ₂ (MoO ₄ ) ₃ · nH ₂ O) and other ores, and among these, industrial use of molybdenite is progressing.
The hydropyrite is often produced together with copper sulfide, and copper and molybdenum are selected from the hydropyrite by flotation, and the recovered molybdenum concentrate generally contains several percent copper sulphide. Things are mixed. When this is used as a steel additive, which is the main use of molybdenum, it is necessary to remove copper from the molybdenum concentrate in advance because copper deteriorates the properties of the steel product.

As a method for separating and recovering copper from a copper-containing molybdenum concentrate, a so-called iron chloride method as described in Non-Patent Document 1, Patent Documents 1 and 2 is conventionally known. In this method, the copper-containing molybdenum concentrate is leached in an autoclave heated to about 110 ° C. using a leachate containing about 120 g / L of Fe ³⁺ ions, so that copper is leached preferentially, and molybdenum And copper are separated to obtain decoppered molybdenum concentrate. Thus, the copper-free molybdenum concentrate after leaching copper is subjected to a molybdenum smelting process. On the other hand, the copper in the liquid after leaching obtained by copper leaching is recovered by a cementation method in which cement copper (about 90% of Cu quality) is precipitated by reacting with iron scraps and the like.

Patent Document 1 describes a method of removing impurities such as copper and lead by supplying an iron chloride solution and chlorine gas to molybdenum concentrate under high temperature and high pressure.
Patent Document 2 discloses a method in which an aqueous solution containing an alkali metal or alkaline earth metal chloride is used as a leachate in order to remove impurities such as copper and lead from molybdenum concentrate.

Patent Document 3 describes a method for separating and recovering copper from sulfide ore containing copper, but here, only the use of air without using a special oxidizing agent or a special device in a chlorination bath. Describes leaching and recovering 98% or more of copper in copper sulfide ore. More specifically, a copper mineral is added to an acidic solution (hereinafter referred to as an “acidic solution”) containing an alkali metal or alkaline earth metal chloride and bromide and copper and iron chloride or copper and iron bromide, While blowing air into the acidic solution at atmospheric pressure and below the boiling point of the aqueous solution, copper is leached from the raw material as monovalent copper and divalent copper by the oxidizing power of one or both of iron ions and copper ions in the acidic solution. Next, solid-liquid separation is performed, and air is blown into the solution after the solid-liquid separation to oxidize copper in the solution and coprecipitate iron and impurities leached from the raw material into the acidic solution. Then, while extracting copper from the post-oxidation liquid which isolate | separated the deposit containing a coprecipitate, the extracted copper is collect | recovered as a copper sulfate in a sulfuric acid solution, and copper is collect | recovered from this copper sulfate solution. It is described that the acid generated at the time of copper extraction is repeatedly used for copper leaching.

US Pat. No. 4,500,006 US Pat. No. 3,744,424 JP 2009-256664 A

In the iron chloride method as described in Non-Patent Document 1 and Patent Documents 1 and 2, a relatively large amount of molybdenum may be leached together with copper and contained in the liquid after leaching during copper leaching treatment. It was solved.
This is described in Table V of Patent Document 2 in which the concentration of molybdenum contained in the leached solution obtained by leaching and removing copper is 0.26 to 5.1 g / L, and the average is 1.42 g / L. It is also understood from the relatively high. In particular, in this test described in Patent Document 2, a molybdenum concentrate having a low copper content of 0.2 to 1.0% by weight is used, and the copper content is generally as high as about 5%. In copper-containing molybdenum concentrates, it is expected that the amount of molybdenum contained in the liquid after leaching and not recovered will further increase.

And in the method described in said patent document etc., since the molybdenum leached in the liquid after leaching is not collect | recovered, the recovery rate of molybdenum becomes a low thing.
Therefore, in order to increase the recovery rate of molybdenum by such an iron chloride method, it is necessary to effectively recover molybdenum eluted from the raw material such as copper-containing molybdenum ore into the solution after leaching.

On the other hand, the method described in Patent Document 3 is a method in which copper is leached from a copper sulfide ore using a chloride bath, and no attention is paid to the recovery of molybdenum. When applied to the recovery of molybdenum from raw materials such as ores, it was also found that molybdenum was slightly contained in the liquid after leaching after copper leaching.
Even in this case, it is desired to effectively recover the molybdenum contained in the liquid after leaching in order to further increase the recovery rate of molybdenum.

This invention makes it a subject to solve such a problem, The place made into it is obtained by leaching the copper component in scraps, such as electronic components, and copper-containing molybdenum ore, for example An object of the present invention is to provide a method for separating molybdenum and a method for treating copper-containing molybdenum ore which can effectively recover molybdenum contained in an acidic solution containing copper ions, iron ions and molybdenum ions, such as a solution after leaching.

As a result of intensive studies, the inventors adjusted the pH of an acidic solution containing copper ions, iron ions, and molybdenum ions within a predetermined range, and precipitated at least a portion of the iron ions contained therein as an iron compound. We have found that most or nearly all of the molybdenum contained in the solution co-precipitates with the iron. Then, it was considered that molybdenum can be effectively recovered from the acidic solution.

Under such knowledge, the method for separating molybdenum according to the present invention is a method for separating molybdenum from an acidic solution containing copper ions, iron ions and molybdenum ions, which oxidizes iron ions in the acidic solution. By adjusting the pH of the acidic solution to 0.5 to 3.0, at least a part of the iron ions is precipitated as an iron compound, and molybdenum ions in the acidic solution are precipitated as a solid to separate molybdenum. There is to do.

Here, in oxidizing the iron ions in the acidic solution, it is preferable to blow an oxygen-containing gas into the acidic solution.
Here, it is preferable that the separation rate of molybdenum separated as a solid by oxidation of the iron ions is 95% or more with respect to the amount of molybdenum contained in the acidic solution.
And it is preferable that the copper quality in the oxidation residue obtained by oxidation of the iron ions is 0.5 mass% or less.

The acidic solution can be obtained by leaching a copper component in a raw material containing copper and molybdenum in an acidic halogen bath containing iron ions. The raw material containing copper and molybdenum can be a copper-containing molybdenum ore.

The copper-containing molybdenum ore processing method of the present invention is obtained in a copper leaching step after leaching the copper component contained in the copper-containing molybdenum ore in an acidic halogen bath containing iron ions, and after the copper leaching step. An iron oxidation step of oxidizing iron ions in the liquid after leaching and precipitating at least a part of the iron ions as an iron compound, wherein the liquid after leaching is eluted from the copper-containing molybdenum ore in the copper leaching step In the iron oxidation step, the pH of the solution after leaching is adjusted to 0.5 to 3.0 to oxidize the iron ions in the solution after leaching, and the molybdenum ions in the solution after leaching are removed. It is to deposit as a solid.

After the iron oxidation step, it may further include a copper extraction step for extracting at least part of copper ions in the post-oxidation solution obtained in the iron oxidation step. In this case, copper is extracted in the copper extraction step. The post-extraction solution after extraction is preferably used for an acidic halogen bath in the copper leaching step.
Moreover, in the said copper leaching process, it is preferable to implement leaching until the copper quality in the obtained leaching residue becomes 0.5 mass% or less.

According to the molybdenum treatment method of the present invention, the iron ions in the acidic solution are oxidized and the pH of the acidic solution is adjusted to 0.5 to 3.0, whereby the iron ions are precipitated as iron compounds. Since most of the molybdenum contained in the acidic solution coprecipitates with the iron, molybdenum can be effectively recovered from the acidic solution.
Further, according to the copper-containing molybdenum ore processing method of the present invention, molybdenum eluted from the copper-containing molybdenum ore in the copper leaching step and recovered in the liquid after leaching is recovered as a solid in the iron oxidation step. It can be recovered effectively without leaving it in the liquid after leaching. As a result, the recovery rate of molybdenum from the copper-containing molybdenum ore can be greatly increased.

It is a flowchart which shows one Embodiment of the separation method of the molybdenum of this invention. It is a flowchart which shows 1st embodiment of the processing method of the copper-containing molybdenum ore of this invention. It is a flowchart which shows the processing method of the copper-containing molybdenum ore which concerns on 2nd embodiment of the processing method of the copper-containing molybdenum ore of this invention. It is a flowchart which shows content of each element contained in the solution thru | or residue of each process of an Example. It is a graph which shows transition of pH and ORP with progress of the oxidation time in the iron oxidation process of an Example, and a graph which shows transition of a liquid concentration.

Hereinafter, embodiments of the present invention will be described in detail.
(1) Method for Separating Molybdenum The method for treating molybdenum according to the present invention is a method for separating molybdenum from an acidic solution containing copper ions, iron ions and molybdenum ions, as illustrated in FIG. By oxidizing the iron ions in the solution and adjusting the pH of the acidic solution to 0.5 to 3.0, at least a part of the iron ions is precipitated as an iron compound, and the molybdenum ions in the acidic solution are solidified. To separate the molybdenum.

Here, as described above, molybdenum is used as an additive or a catalyst in various industrial fields. For example, various metals contained in raw materials such as used electronic devices or parts are used. The acidic solution obtained by acid leaching by crushing an electronic device in order to separate and recover the material may contain iron ions, copper ions, and molybdenum ions that are contained and eluted in the raw material. In the present invention, an acidic solution containing such iron ions, copper ions, and molybdenum ions can be targeted.
Moreover, the acidic solution made into object by this invention contains iron ion, copper ion, and molybdenum ion by leaching the copper component in said raw material containing copper and molybdenum in the acidic halogen bath containing iron ion. Can be obtained as This raw material includes a copper-containing molybdenum ore described later. The acidic halogen bath will be described in detail later.

By oxidizing iron ions in such an acidic solution and adjusting the pH of the acidic solution to 0.5 to 3.0, Fe (II) ions contained in the acidic solution are oxidized to Fe (III) ions. At the same time, some of the Fe (III) ions are effectively precipitated to produce an iron compound.
At this time, with the precipitation of iron, molybdenum ions in the acidic solution are precipitated as a solid and co-precipitated. Thereby, the solid molybdenum can be easily separated from the acidic solution by solid-liquid separation. When the pH of the acidic solution is less than 0.5, there is a concern that precipitation of iron ions and accompanying precipitation of molybdenum ions may not occur sufficiently. On the other hand, if the pH of the acidic solution is larger than 3.0, copper ions contained in the acidic solution may be precipitated, and the oxidized residue contains a large amount of copper, and the separated molybdenum is removed from the steel. It is not desirable when used as an additive. The pH of the acidic solution is more preferably 0.5 to 2.0, and particularly preferably 1.0 to 2.0.

The oxidation of iron ions can also be performed by adding hydrogen peroxide water or the like, but the blowing of oxygen-containing gas is preferable because iron ions can be oxidized easily and inexpensively.
The amount of molybdenum separated as a solid by oxidation of iron ions is preferably 95% or more, expressed as a separation rate with respect to the amount of molybdenum originally contained in the acidic solution. This separation rate can be expressed by (amount of molybdenum precipitated and separated) / (amount of molybdenum contained in the acidic solution) × 100.
In addition, it is preferable that the acid residue containing iron and molybdenum precipitated by oxidation of iron ions contains copper in an amount of 0.5% by mass or less when this is used as a steel additive or the like.

(2) Copper-containing molybdenum ore processing method The copper-containing molybdenum ore processing method of the present invention includes a copper leaching step of leaching a copper component contained in the copper-containing molybdenum ore in an acidic halogen bath containing iron ions, and copper. After the leaching step, an iron oxidation step of oxidizing iron ions in the liquid after leaching obtained in the copper leaching step and depositing at least a part of the iron ions as an iron compound is included.

Although there is no restriction | limiting in particular as copper-containing molybdenum ore made into object by this invention, For example, ore containing one or more selected from molybdenite, molybdenum ore, pawerite, and iron molybdenite, Especially, molybdenite Mention may be made of molybdenum concentrate after flotation of ore containing ore. Copper in the copper-containing molybdenum ore may be present in the form of sulfides, for example in the form of chalcocite and / or chalcopyrite.
The copper-containing molybdenum ore contains Cu in an amount of 0.5 to 10% by mass, preferably 1 to 10% by mass, more preferably 2 to 5% by mass, and the copper-containing molybdenum ore contains 20% by mass or more of Mo. It is possible to target those containing 30 to 60% by mass, more preferably 40 to 50% by mass.

In such a copper-containing molybdenum ore, the copper-containing molybdenum ore processing method of the present invention first performs a copper leaching step. In this copper leaching process, a large amount of molybdenum remains undissolved as a leaching residue, but some molybdenum is eluted together with copper from the copper-containing molybdenum ore and is contained in the liquid after leaching.
As a result of investigation by the inventors on the recovery of molybdenum contained in the liquid after leaching, the molybdenum leached into the liquid after leaching is coprecipitated together with iron in the iron oxidation step in which iron ions in the liquid after leaching are oxidized. It was found that the molybdenum in the liquid after leaching can be recovered as a solid in this iron oxidation process.

Under this knowledge, in the method for treating copper-containing molybdenum ore of the present invention, after the copper leaching step, iron ions in the post-leaching solution obtained in the copper leaching step are oxidized, and at least a part of the iron ions are removed. An iron oxidation step for precipitation as an iron compound is carried out, where the molybdenum contained in the liquid after leaching is recovered as a solid.
Specifically, the processing method of the present invention can be implemented by the embodiment shown in FIG. 2 or 3, for example. Each embodiment is described in detail below.

<First embodiment>
In the embodiment shown in FIG. 2, the copper leaching process, the iron oxidation process, and the copper extraction process are sequentially performed.

(Copper leaching process)
In the copper leaching step, an acidic aqueous solution at 50 to 100 ° C. containing chloride ions at 100 g / L to 200 g / L, copper ions at 1 g / L to 30 g / L, and iron ions at 1 g / L to 50 g / L, respectively ( Hereinafter, the copper component contained in the copper-containing molybdenum ore is leached by bringing the copper-containing molybdenum ore into contact with the copper-containing molybdenum ore under the supply of the oxygen-containing gas. That is, in the copper leaching step, by using an acidic chloride bath as an acidic halogen bath, copper in the copper-containing molybdenum ore is leached, and here, copper ions are present in the leaching solution, The leaching reaction of copper can be promoted.

The concentration of chloride ions in the leaching solution used in the copper leaching step is preferably 100 g / L or more, more preferably 120 g / L or more, from the viewpoint of realizing a copper dissolution reaction with high efficiency. Further, it is particularly preferably 140 g / L or more. However, in consideration of economy, it is not necessary to make the concentration too high, and the concentration of chloride ions in the leachate is generally 200 g / L or less, preferably 180 g / L or less.

The concentration of copper ions in the leaching solution used in the copper leaching step is preferably 1 g / L or more, and more preferably 5 g / L or more, from the viewpoint of promoting the copper leaching reaction. However, in consideration of economy, it is not necessary to make the concentration too high, and the concentration of copper ions in the leachate is generally 30 g / L or less, preferably 20 g / L or less.

Iron ion is a suitable component for promoting copper leaching, and is preferably 1 g / L or more from the viewpoint of realizing a copper dissolution reaction with high efficiency, but if it exceeds 50 g / L, the leaching rate of Mo is remarkable. To increase and lose. In order to prevent this, the iron ion concentration in the leachate can be 50 g / L or less, preferably 10 g / L or less. The iron ion concentration is particularly preferably 8 g / L or less, and more preferably 6 g / L or less.

From the viewpoint of preventing molybdenum leaching, the total of copper ions and iron ions in the leaching solution is preferably 25 g / L or less, and more preferably 20 g / L or less.
In addition, the density | concentration of said chloride ion, copper ion, and iron ion points out the density | concentration in the leaching solution before making acidic aqueous solution contact copper-containing molybdenum ore.

The contact method between the leachate and the copper-containing molybdenum ore is not particularly limited, and there are methods such as spraying and dipping. From the viewpoint of reaction efficiency, a method of dipping and stirring the copper-containing molybdenum ore in the leachate is preferable.

It is important to carry out the copper leaching process while supplying an oxygen-containing gas to the leaching solution. By supplying the oxygen-containing gas, the copper leaching rate can be increased. By increasing the flow rate of the oxygen-containing gas, the copper leaching rate tends to increase. Thereby, since leaching of copper proceeds before leaching of molybdenum, loss of molybdenum can be suppressed. Although there is no restriction | limiting in particular as oxygen-containing gas, For example, the mixed gas of air, oxygen, oxygen, and inert gas (nitrogen, a noble gas, etc.) is mentioned. Air is preferable from the viewpoint of economy.

The oxygen-containing gas is preferably supplied at a flow rate of 0.02 L / min or more per liter of the leachate from the viewpoint of effectively exhibiting the above-described effects, and more preferably supplied at a flow rate of 0.04 L / min or more. It is even more preferable to supply at a flow rate of 0.08 L / min or more. However, if it is supplied excessively, it consumes a lot of energy such as electric power to compensate for the heat of evaporation taken away by evaporation of the liquid into the bubbles, and a layer of bubbles with concentrate particles coated on the surface ( Floss) is generated in large quantities and overflows from the reaction tank. Therefore, it is preferable to supply at a flow rate of 0.5 L / min or less per liter of the leachate, more preferably at a flow rate of 0.25 L / min or less per liter of the leachate, and further 0.15 L per liter of the leachate. It is even more preferable to supply at a flow rate of / min or less.

The supply source of chloride ions is not particularly limited, and examples thereof include hydrogen chloride, hydrochloric acid, and metal chloride. However, in consideration of economy and safety, supply in the form of metal chloride is preferable. Examples of the metal chloride include copper chloride (cuprous chloride, cupric chloride), chlorides of alkali metals (lithium, sodium, potassium, rubidium, cesium, francium), alkaline earth metals (beryllium, magnesium, calcium, (Strontium, barium, radium) chlorides are mentioned, and sodium chloride is preferable from the viewpoint of economy and availability. Moreover, since it can utilize also as a supply source of copper ion, it is also preferable to utilize copper chloride.

Copper ions and iron ions are usually supplied in the form of a salt, and can be supplied, for example, in the form of a halide salt. From the viewpoint that it can also be used as a supply source of chloride ions, copper ions are preferably supplied as copper chloride and iron ions as iron chloride. It is desirable to use cupric chloride (CuCl ₂ ) and ferric chloride (FeCl ₃ ) as copper chloride and iron chloride, respectively, from the viewpoint of oxidizing power, but cuprous chloride (CuCl) and ferric chloride. monoferric even when using the (FeCl _2), by supplying an oxygen-containing gas in the leaching solution, to be oxidized respectively cupric (CuCl ₂₎ and ferric chloride (FeCl _3), There is no big difference.

In order to increase the copper leaching efficiency from the copper-containing molybdenum ore, the leaching solution should be acidic, and since it can be used as a supply source of chloride ions, it is preferably made acidic with hydrochloric acid. The pH of the leaching solution is preferably about 0 to 3, more preferably about 0.2 to 2.5, as measured by the glass electrode, in order to ensure the solubility of the leached copper.

From the above, a mixed solution of hydrochloric acid, cupric chloride, ferric chloride, and sodium chloride can be used as the leaching solution in the copper leaching step.

The temperature of the leaching solution used in the copper leaching step is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, and even more preferably 70 ° C. or higher, from the viewpoint of leaching efficiency and material of the apparatus. . On the other hand, if the temperature of the leachate is too high, the leachate will evaporate and the heating cost will increase, so it is preferably 100 ° C. or less, more preferably 90 ° C. or less, and 85 ° C. or less. Even more preferred. Although it is possible to carry out the copper leaching step under pressure for the purpose of increasing the leaching efficiency, it is sufficient under atmospheric pressure. This makes it possible to use a simpler apparatus without requiring a pressure vessel for performing the leaching process at high pressure. In order to promote copper leaching, it is preferable to pulverize and grind the copper-containing molybdenum ore to be treated in advance.

The copper leaching step is preferably carried out with an increased amount of copper-containing molybdenum ore with respect to the leaching solution used from the viewpoint of reducing the leaching cost. Therefore, for example, the leaching step can be performed at a pulp concentration of 50 g / L or higher, the leaching step can be performed at a pulp concentration of 150 g / L or higher, and the pulp concentration of 300 g / L or higher is further achieved. The leaching process can be performed. On the other hand, from the viewpoint of increasing the leaching rate, since it is preferable that the amount of the copper-containing molybdenum ore with respect to the leaching solution used is small, the leaching step can be performed at a pulp concentration of 800 g / L or less, and 600 g The leaching step can be performed at a pulp concentration of / L or less, and the leaching step can be performed at a pulp concentration of 500 g / L or less. Here, the pulp concentration is the ratio of the copper-containing molybdenum ore (dry weight (g)) to the volume (L) of the leachate used.

It is preferable to carry out the copper leaching until the copper component in the copper-containing molybdenum ore is sufficiently leached, specifically, until the copper grade in the leaching residue is 0.5% by mass or less. Thereby, the leaching residue from which copper is sufficiently removed can be effectively used, for example, as a steel additive.
After the leaching of copper is completed, the obtained leaching reaction liquid is separated into a liquid after leaching and a leaching residue by solid-liquid separation using a filter press, a thickener or the like.

Here, copper leaching in the copper leaching step can be performed only once, but it is preferable to repeat the process by replacing the acidic halogen bath. Thereby, the molybdenum purity in the copper-free molybdenum ore which is the leaching residue is increased to increase the market value, and an advantage that more copper can be recovered is obtained. When copper leaching is repeated multiple times, specifically, after the first copper leaching is completed, solid-liquid separation is performed with a filter press, thickener, etc., and the leaching residue is second time, as required. It can be carried out by leaching copper after the third time. Typically, copper leaching can be performed two to four times.

In this embodiment shown in FIG. 2, copper can be leached at a high leaching rate while suppressing leaching of molybdenum into the solution after leaching. For example, it is possible to achieve a copper leaching rate of 70% or more while suppressing the molybdenum concentration in the liquid after leaching to 0.001 g / L or less, or the molybdenum concentration in the liquid after leaching is 0.005 g / L. While suppressing below, copper leaching rate of 90% or more can be achieved, and depending on conditions, the copper leaching rate is 95% while suppressing the molybdenum concentration in the liquid after leaching to 0.005 g / L or less. The above can be achieved. In this regard, the embodiment of FIG. 2 is more advantageous than the embodiment of FIG.

The time required for the leaching depends on the copper quality in the copper-containing molybdenum ore as the raw material, but the time required for the copper quality in the leaching residue to be 0.5% by mass or less is about 4 to 10 hours, for example. Yes, typically around 5-6 hours.

(Iron oxidation process)
The leached solution obtained by the copper leaching step contains iron ions in which part of iron in the copper-containing molybdenum ore is dissolved, in addition to iron ions originally contained in the leaching solution. Many of these iron ions are thought to be Fe (II).
In this iron oxidation process, the above iron ions are oxidized to Fe (III) and used again for leaching, and the pH is adjusted to precipitate a part of Fe (III) to produce an iron compound. By doing so, the iron concentration in the leachate can be controlled. Here, Cu (I) in the solution after leaching is also oxidized to Cu (II).

Here, as described above, the leached solution contains a small amount of molybdenum eluted in the copper leaching process, and in this embodiment, iron ions are oxidized in the iron oxidation process in order to recover this molybdenum. By doing so, molybdenum is co-precipitated with the iron compound in which iron ions are deposited, and this is recovered as a solid. Thereby, the recovery rate of molybdenum can be increased effectively.

Iron oxidation in the iron oxidation step can be performed at room temperature, but may be heated a little to accelerate the reaction. Specifically, the temperature of the liquid after leaching here can be set to 20 to 70 ° C., for example.

In this iron oxidation step, the pH of the solution after leaching is set within the range of 0.5 to 3.0 in order to effectively oxidize iron ions and prevent precipitation of copper ions. The reason for this is that if the pH of the solution after leaching is less than 0.5, iron ions may not be precipitated, and thereby molybdenum co-precipitated with iron may not be sufficiently precipitated. On the other hand, if the pH of the solution after leaching exceeds 3.0, precipitation of copper ions may occur.
From such a viewpoint, the pH of the solution after leaching in the iron oxidation step is more preferably 0.5 to 2.0, and still more preferably 1.0 to 2.0.

The oxidation of iron in the iron oxidation process includes the addition of hydrogen peroxide water to the solution after leaching or the blowing of oxygen-containing gas such as oxygen, oxygen and inert gas (nitrogen, rare gas, etc.) However, it is particularly preferable to carry out by blowing oxygen-containing gas. Among these, it is preferable in terms of cost to blow air.
When the oxygen-containing gas is blown, it is preferably supplied at a flow rate of 0.01 L / min to 1.5 L / min per liter of the leached liquid. 0.01 L / min is a supply amount that does not lower the dissolved oxygen in water at 60 ° C. Thus, if the supply flow rate of the oxygen-containing gas is too small, it takes time to oxidize. On the other hand, when the supply flow rate of the oxygen-containing gas is too large, a large amount of energy such as electric power is consumed to compensate for the heat of evaporation taken away by the evaporation of the liquid into the bubbles.

By performing the iron oxidation step under such conditions, the recovery rate of molybdenum in the iron oxidation step, that is, the ratio of the amount of molybdenum in the oxidation residue to the amount of molybdenum in the liquid after leaching is 95. % Or more is preferable. Depending on the molybdenum concentration in the liquid after leaching and the oxidation conditions, it is possible to recover almost all of the molybdenum contained in the liquid after leaching.

The oxidation residue obtained in the iron oxidation process contains molybdenum in the liquid after leaching as a solid, so in addition to the leaching residue obtained in the copper leaching process described above, these are the main applications of molybdenum. It can be used as a certain steel additive.
However, when these residues are used as a steel additive, the properties of the steel product are lowered if a large amount of copper is contained therein, so that the copper quality in the residue is preferably small. Specifically, the copper quality in the oxidation residue is preferably 0.5% by mass or less.

(Copper extraction process)
In the copper extraction step, copper can be recovered from the post-oxidation solution after the iron oxidation step. Although there is no restriction | limiting in particular as a copper collection | recovery method here, For example, solvent extraction, ion exchange, substitution precipitation with a base metal, electrowinning, etc. can be utilized. The copper in the solution after oxidation has both monovalent and divalent states. However, in order to perform solvent extraction and ion exchange smoothly, the copper should be oxidized beforehand so that it becomes divalent copper ions. Is preferred. The method of oxidation is not particularly limited, but a method of blowing air or oxygen into the solution after oxidation is simple.

This copper extraction step further includes a process of recovering copper in the solution after oxidation as electrolytic copper on the cathode by electrolytic extraction after subjecting it to solvent extraction and back extraction. This process is generally called a SX-EW (Solvent® Extraction® and Electro-Winning) method and is well known to those skilled in the art.

Also, before the solvent extraction, an oxygen-containing gas such as air can be blown into the post-oxidation solution to oxidize copper in the solution. This provides the advantage that copper can be back extracted (striped) after solvent extraction and directly electrowinned. When the oxidation treatment is not performed, monovalent copper is present in a high concentration in the strong chloride bath, so that it is deposited as dendritic copper during electrowinning. Dendritic copper precipitates in the electrolytic cell as a metal powder. It is overwhelmingly more advantageous in terms of operability such as transportation when recovered as plate-like copper on the cathode. Furthermore, solid-liquid separation can also be performed after the oxidation treatment. Solid-liquid separation is advantageous in increasing the purity of copper in the liquid after leaching because it moves to the residue after oxidation when iron is contained in the leaching liquid.

The post-extraction liquid (copper post-extraction liquid) obtained after such a copper extraction process may contain copper ions and iron ions. In this case, the post-extraction liquid is acidified in the copper leaching process described above. It is preferred to use repeatedly as a halogen bath leaching solution. In the present invention, as described above, molybdenum is sufficiently removed from the liquid after leaching in the iron oxidation process, so that the liquid after extraction obtained in the copper extraction process is substantially free of molybdenum, As described above, the liquid after extraction can be effectively circulated and used.

(Molybdenum recovery process)
The leaching residue obtained in the copper leaching step can be used as molybdenum concentrate to produce a molybdenum intermediate product through a purification process known to those skilled in the art. For example, molybdenum trioxide products can be produced by oxidation roasting, molybdenum trioxide briquettes can be produced through molding and drying processes, and low carbon ferromolybdenum can be produced through thermite reduction. Furthermore, it is possible to obtain metallic molybdenum by performing ammonia extraction and hydrogen reduction after oxidative roasting and desulfurization.

<Second embodiment>
Another embodiment shown in FIG. 3 is a method commonly known in the art as the so-called iron chloride method. The treatment method of the present invention can be applied to the iron chloride method as described below.
In this method shown in FIG. 3, first, a copper leaching process is performed in which copper-containing molybdenum ore is leached in an autoclave heated to about 110 ° C. using a leaching solution. The leaching solution here contains, for example, Fe ³⁺ ions at about 100 g / L to 120 g / L, halide ions at about 300 g / L to 350 g / L, and further contains copper ions. it can. Examples of the halide ions include chloride ions and bromide ions. Among them, chloride ions are generally used.

Next, a cementation process is performed on the leached solution obtained in this copper leaching process. Here, the copper in the leachate is allowed to react with iron scraps or the like, thereby precipitating cement copper (Cu quality of about 90%).

Then, an iron oxidation process is performed with respect to the solution obtained at the cementation process. Here, in the iron chloride method, the iron ions are usually oxidized from divalent to trivalent without precipitating the iron by blowing in chlorine gas. By precipitating in the form of a site, Mo dissolved in the above solution can be coprecipitated and recovered. If necessary, the iron oxidation step may be performed separately from the iron oxidation step using chlorine gas and the iron oxidation step using oxygen-containing gas.
In the iron chloride method, since a large amount of molybdenum is leached together with the copper contained in the copper-containing molybdenum ore by the above leaching treatment, the leached solution contains a relatively large amount of molybdenum. Therefore, as described above, it is effective to precipitate and recover molybdenum in the solution obtained by performing the cementation step on the leached solution in the iron oxidation step.
In addition, the solution after iron and molybdenum are collect | recovered by an iron oxidation process can be used again as a leaching liquid for the leaching process of the copper in a copper-containing molybdenum ore as mentioned above.

Next, the present invention was experimentally implemented and will be described below. However, the description here is provided for illustrative purposes only and is not intended to be limiting.

The raw material containing copper and molybdenum was pulverized and processed according to the flow shown in FIG. When the residue in each step and the molybdenum, copper and iron contained in the solution were analyzed by ICP emission spectroscopy (ICP-OES), the results shown in FIG. 4 were obtained.

In the copper leaching step, a leaching solution (Cu leaching solution) mixed with hydrochloric acid, ferric chloride, cupric chloride, and sodium chloride was heated to 75 ° C. with a hot stirrer, and the raw materials were added thereto. Stirring while blowing air.
In the iron oxidation step, the temperature of the liquid after leaching was set to 60 ° C., and air was blown into the liquid after leaching at 0.15 L / min for oxidation for 8 hours. The transition of pH and ORP with the lapse of oxidation time at that time is shown in a graph in FIG.

From the results shown in FIG. 4, in the copper leaching process, 99.8% of the molybdenum in the raw material could be recovered as a leaching residue, but the remainder was slightly eluted and contained in the liquid after leaching. became.
After that, by performing an iron oxidation process, all of the molybdenum contained in the solution after leaching was coprecipitated with iron and recovered into an oxidation residue, so that the solution after oxidation did not contain molybdenum. .

Further, from the graph shown in FIG. 5, since the concentration of iron in the liquid after leaching is effectively reduced after the pH of the liquid after leaching becomes 0.5 or more, precipitation of molybdenum co-precipitated with iron. It can be seen that the pH of the solution after leaching is preferably 0.5 or more in order to effectively promote the above.

In addition, when the oxidation residue obtained in this iron oxidation process was examined, the Mo concentration in the residue was low and the detailed form of precipitated Mo could not be confirmed, but X-ray diffraction (XRD) or automatic mineral analysis As a result of the test using the apparatus (MLA), a compound of Mo and Fe was not confirmed, and most of Fe was goethite FeOOH. Therefore, in the iron oxidation process, Mo is a common Fe compound. It is thought that it settles by sedimentation.

From the above results, according to this method, molybdenum in the liquid after leaching obtained in the copper leaching step can be effectively recovered as a solid, and as a result, the recovery rate of molybdenum from the raw material containing copper and molybdenum. It was found that can be further improved.

Claims (9)

1. A method for separating molybdenum from an acidic solution containing copper ions, iron ions and molybdenum ions,
   By oxidizing iron ions in the acidic solution and adjusting the pH of the acidic solution to 0.5 to 3.0, at least a part of the iron ions is precipitated as an iron compound, and molybdenum in the acidic solution A method for separating molybdenum, in which ions are deposited as a solid to separate molybdenum.
2. The method for separating molybdenum according to claim 1, wherein an oxygen-containing gas is blown into the acidic solution when oxidizing the iron ions in the acidic solution.
3. The method for separating molybdenum according to claim 1 or 2, wherein a separation rate of molybdenum separated as a solid by oxidation of the iron ions is set to 95% or more with respect to an amount of molybdenum contained in the acidic solution.
4. The method for separating molybdenum according to any one of claims 1 to 3, wherein a copper grade in an oxidation residue obtained by oxidation of the iron ions is 0.5 mass% or less.
5. The method for separating molybdenum according to any one of claims 1 to 4, wherein the acidic solution is obtained by leaching a copper component in a raw material containing copper and molybdenum in an acidic halogen bath containing iron ions.
6. The method for separating molybdenum according to claim 5, wherein the raw material containing copper and molybdenum is copper-containing molybdenum ore.
7. Copper leaching process in which copper components contained in copper-containing molybdenum ore are leached in an acidic halogen bath containing iron ions, and after the copper leaching process, iron ions in the leached liquid obtained in the copper leaching process are oxidized. And an iron oxidation step for precipitating at least part of the iron ions as an iron compound,
   The leached liquid contains molybdenum ions eluted from the copper-containing molybdenum ore in the copper leaching step,
   In the iron oxidation step, the pH of the liquid after leaching is adjusted to 0.5 to 3.0 to oxidize iron ions in the liquid after leaching and precipitate molybdenum ions in the liquid after leaching as a solid. Treatment method for copper molybdenum ore.
8. After the iron oxidation step, further comprising a copper extraction step for extracting at least part of the copper ions in the post-oxidation solution obtained in the iron oxidation step,
   The processing method of the copper-containing molybdenum ore of Claim 7 which uses the liquid after extraction after extracting copper by the said copper extraction process for the acidic halogen bath of a copper leaching process.
9. The method for treating copper-containing molybdenum ore according to claim 7 or 8, wherein, in the copper leaching step, leaching is performed until the copper grade in the obtained leaching residue is 0.5 mass% or less.

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