JP6163392B2 - Germanium recovery method - Google Patents

Description

  The present invention relates to a method for recovering germanium from a solution containing germanium.

Germanium (Ge) is a material for so-called high-tech industries such as optical fibers and solar cells, a polymerization accelerating catalyst for polyethylene terephthalate resin, and an organic germanium compound (for example, poly-trans-[(2-carboxyethyl) germaseski Oxane]) is an indispensable element in various fields as a raw material for production.
Particularly recently, the use of germanium as an electronic material such as a magnetic disk material has increased, and the demand for high-quality germanium with a low content of arsenic and non-ferrous metals has increased.

  However, in recent years, the supply of germanium has not been able to keep up with the demand, and it has been regarded as a problem because the demand-supply balance continues to be unbalanced. Therefore, if high-quality germanium, which is mainly smelted as a byproduct of zinc smelting, can be recovered efficiently and inexpensively at a high recovery rate, the balance between demand and supply will be improved, and resource resources will be improved. It is also preferable from the viewpoint of saving.

Conventionally, as a method for recovering germanium contained in zinc concentrate, zinc concentrate is roasted, the leaching residue after leaching with acid is dried, heated, and then germanium salified with hydrochloric acid is recovered (Eagle- (Picher method) is known (see Non-Patent Document 1).
However, the method according to this document has a problem that the recovery rate of germanium from the zinc concentrate is low and it cannot be stably recovered.

Therefore, the applicant of the present application first includes a germanium chloride recovery step of recovering germanium as chloride from a germanium-containing intermediate in a metal recovery step by using hydrochloric acid and hydrogen peroxide in combination. A collection method is proposed (see Patent Document 1). According to this method, the recovery rate of germanium can be improved to some extent as compared with the conventional method.
However, in the proposed method, germanium is concentrated with an intermediate containing germanium in the indium recovery step, and germanium is recovered from the concentrate. The germanium concentration step is a substitution process, and since the germanium recovery rate here is poor, there is a problem that a high germanium recovery rate cannot be obtained. For this reason, if it is going to raise the recovery rate of germanium in a substitution process, problems, such as an increase in zinc powder cost and zinc mixture in an indium sponge, will generate | occur | produce.

  Therefore, a method for recovering high-grade germanium from a solution containing germanium at a high recovery rate efficiently and inexpensively has not yet been provided, and there is a strong demand for prompt provision. It is.

Rare Metal Handbook 2008, metal review

JP 2012-91968 A

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, an object of the present invention is to provide a method for recovering germanium from a solution containing germanium efficiently and inexpensively at a high recovery rate with high quality germanium.

  The method for recovering germanium according to the present invention as a means for solving the above-described problems includes a germanium sulfide process for recovering germanium as a sulfide by adding sodium hydrosulfide and sulfuric acid to a solution containing germanium. Features.

  According to the present invention, conventional problems can be solved, and a method for recovering germanium from a solution containing germanium at a high recovery rate, efficiently and inexpensively can be provided. .

1 is a graph showing the relationship between the amount of sodium hydrosulfide added and the Ge concentration in Example 1. FIG. FIG. 2 is a graph showing the relationship between the Zn powder addition amount and the Ge concentration in Comparative Example 1. FIG. 3 is a graph showing the relationship between temperature and Ge concentration in Example 2.

(Recovery method of germanium)
The method for recovering germanium according to the present invention includes at least a germanium sulfide step, and further includes other steps as necessary.
Preferably, the solution containing germanium includes indium and cadmium, and includes a step of recovering indium from the solution after the sulfide is recovered in the germanium sulfide step.

<Germanium sulfide process>
The germanium sulfiding step is a step of adding germanium hydrosulfide and sulfuric acid to a solution containing germanium and recovering germanium as a sulfide.
About the method of recovering germanium of the present invention, in the conventionally known Eagle-Pitcher method (rare metal handbook 2008, metal review, p.164), sodium hydrosulfide and sulfuric acid are used in combination. A germanium sulfide process for recovering germanium as a sulfide will be described.
In zinc smelting, sulfide concentrate is generally roasted and various metals are separated into residues and liquids by leaching with acid and neutralization treatment. It is possible to generate a germanium enriched residue from such a zinc smelting process. In particular, the intermediate product used in the indium recovery process derived from the zinc smelting process contains germanium at a relatively high concentration, and can be used as a raw material (a solution containing germanium) of the present invention. .

-Solution containing germanium-
The germanium-containing solution (raw material) is obtained in the metal recovery step (treatment) and is not particularly limited as long as it contains germanium, and can be appropriately selected according to the purpose. Incineration of waste liquid from the production of non-ferrous smelting intermediate products such as residues generated by smelting processes such as oxidation and acid leaching of germanium-containing ores such as zinc ore and polyethylene terephthalate and polyester based on them Ash obtained in this way, MCVD processing waste, intermediate products such as recovery of rare metals such as the material after being used as a semiconductor material or waste generated in the production thereof. Among these, a solution obtained by acid leaching of an intermediate product in zinc smelting is preferable.
The form of the raw material is not particularly limited as long as it can react with sulfuric acid, and may be, for example, a form of a metal compound or a form of a complex compound including an organic substance other than an inorganic substance.

In the Eagle-Pitcher method, first, zinc concentrate containing germanium (the content ratio of germanium is usually 0.01% by mass to 0.015% by mass) is oxidized and roasted. Mix salt and coal and sinter. The sintered residue becomes a raw material for zinc smelting, but volatiles (smoke ash) generated during sintering include germanium, cadmium, copper, lead, and the like.
Next, the volatiles are leached with sulfuric acid and filtered to remove lead sulfide, and zinc powder is added to the obtained filtrate. Thereby, since germanium and copper are substituted with zinc, germanium and copper are aggregated and precipitated while cadmium remains in the solution.
Furthermore, by adding sulfuric acid and zinc powder to the obtained precipitate, copper is left in the solution, and germanium is aggregated and precipitated. After the precipitate is collected by filtration, the filtrate is dried and heated, and the resultant is used as a raw material for the germanium sulfide process. The above is a normal process in the Eagle-Pitcher method.

In the method for recovering germanium of the present invention, before the substitution treatment for adding zinc powder, sodium hydrosulfide and sulfuric acid are added to the raw material (a solution containing germanium) to recover germanium sulfide.
By adding sodium hydrosulfide and sulfuric acid before the substitution treatment of adding zinc powder, the recovery rate of germanium can be greatly improved. Further, since impurities such as Sn and Pb become solid due to germanium sulfide (included in the residue), filtration after the neutralization step is not necessary.
Since the filtration after the neutralization step is not required before the substitution treatment for adding the zinc powder, it is possible to increase the recovery rate of germanium without increasing the number of steps and adversely affecting the indium recovery step. However, if the germanium remaining in the solution without being precipitated by the substitution treatment in which zinc powder is added is collected using sodium hydrosulfide and sulfuric acid in combination, the number of steps is increased, and the collection cost is greatly increased.
There is no restriction | limiting in particular about the addition order of the said sodium hydrosulfide and the said sulfuric acid, which may be added first and may be added simultaneously. Moreover, there is no restriction | limiting in particular as the addition method of the said sodium hydrosulfide and the said sulfuric acid, Although it can select suitably according to the objective, For example, it is preferable to mix two reagents before contact with an object liquid. . This is because when added separately, the filterability may deteriorate and the impurity quality in the germanium sulfide may increase. In addition, another chemical | medical agent may be further added if the sulfidation of germanium can be accelerated | stimulated.

The germanium sulfiding step is preferably performed at a temperature of 30 ° C to 70 ° C. The temperature here is the temperature of the mixed solution when sodium hydrosulfide and sulfuric acid are added to the stock solution and sulfidized. If the temperature is lower than 30 ° C, the filterability of germanium sulfide may be deteriorated. If the temperature is higher than 70 ° C, germanium is not easily sulfided, and the amount of sodium hydrosulfide necessary for sulfidation is excessive, resulting in a recovery cost. May increase significantly.
The free sulfuric acid (FA) concentration in the germanium sulfiding step is preferably 20 g / L to 100 g / L, and more preferably 80 g / L to 100 g / L. If the free sulfuric acid concentration is less than 20 g / L, the quality of germanium sulfide impurities (Zn, In) may increase, and if it exceeds 100 g / L, germanium tends to be redissolved during filtration after the reaction. Sometimes.

<Other processes>
In the germanium oxide recovery step, which is a normal step in the Eagle-Pitcher method, water is added to the recovered germanium sulfide and hydrolyzed to recover germanium (germanium dioxide) as an oxide.
In the hydrolysis, the amount of water with respect to the germanium sulfide is preferably 2 to 100 times, more preferably 2 to 5 times, from the viewpoint of sufficiently performing the reaction. Moreover, it is preferable to perform the said hydrolysis at 10 to 30 degreeC.

  The germanium recovery method of the present invention is capable of recovering high-quality germanium efficiently and inexpensively at a high recovery rate. Therefore, development of materials for so-called high-tech industries such as optical fibers and solar cells, polymerization promotion catalyst for polyethylene terephthalate resin It is suitable as a method for recovering germanium that can be used for semiconductor elements such as diodes and transistors, electronic materials such as phase change magnetic disk materials, catalysts, and other raw materials for processing.

  Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1
As a raw material for recovering germanium (Ge), zinc concentrate obtained by importing overseas (the content of germanium contained in the zinc concentrate is about 0.01% to 0.015% by mass) is oxidized and roasted. The residue (intermediate product) after leaching zinc (Zn) with acid is subjected to a leaching treatment using sulfuric acid, and copper (Cu), lead (Pb) and tin (Sn) are recovered as residues. Solution (hereinafter referred to as “stock solution”) was used.
The ingredients of the stock solution are shown in Table 1. In addition, each content of the said component was measured using ICP emission spectral analysis.

<Germanium (Ge) sulfide conditions>
A mixture of 15% by mass sodium hydrosulfide (NaSH) and 24% by mass sulfuric acid in advance was added to 1,400 mL of the stock solution in a thermostatic bath at an addition rate of 0.5 mL / min. The set temperature of the thermostatic bath was 70 ° C., the 15 mass% sodium hydrosulfide used was 75.5 mL, and the 24 mass% sulfuric acid was 38.0 mL. The reaction principle is as shown in the following reaction formula.
<Reaction formula>
GeO ₂ + 2NaSH + H ₂ SO ₄ → GeS ₂ + Na ₂ SO ₄ + 2H ₂ O

  After sulfurization, filtration was performed using a filter press to obtain a filtrate and germanium sulfide. The filtrate composition after filtration is shown in Table 2 and FIG.

表２及び図１の結果から、原液中のゲルマニウム（Ｇｅ）濃度は４２６ｍｇ／Ｌから２８ｍｇ／Ｌまで低下し、９３％のゲルマニウムをゲルマニウム硫化物として回収できた。
不純物のＳｎ、Ｐｂは、ゲルマニウム硫化物中に取り込まれ、ろ液中のＳｎ、Ｐｂ濃度はいずれもＩＣＰ発光分光分析の検出下限値以下になった。
中和前に原液中の不純物が除去されるため、従来行われていた中和でのろ過（Ｓｎ、Ｐｂの除去）が不要となる。また、Ｃｄも一部ゲルマニウム硫化物中に取り込まれるが、約半分は液中に残る。 <Filtration composition after sulfurization>

From the results of Table 2 and FIG. 1, the germanium (Ge) concentration in the stock solution decreased from 426 mg / L to 28 mg / L, and 93% of germanium was recovered as germanium sulfide.
Impurities Sn and Pb were incorporated into germanium sulfide, and the Sn and Pb concentrations in the filtrate were both below the detection lower limit of ICP emission spectroscopic analysis.
Since impurities in the undiluted solution are removed before neutralization, filtration (removal of Sn and Pb) in neutralization that has been conventionally performed becomes unnecessary. Cd is also partially incorporated into the germanium sulfide, but about half remains in the liquid.

<Others>
The recovered germanium sulfide was subjected to oxidative leaching, hydrolysis, and the like to remove impurities such as Cd, Sn, and Pb, and germanium was recovered from the germanium sulfide as germanium dioxide.
In addition, the sulfurized liquid obtained in Example 1 was neutralized in the same manner as Comparative Example 1 below, and zinc powder was added to the neutralized solution to perform a substitution treatment, and the precipitate was leached with hydrochloric acid. Then, when electrolytic recovery of indium from the leachate was performed, the recovery rate of indium calculated from the concentration of indium in the liquid before and after electrolytic recovery was 95%. The results of the recovery rates of germanium and indium are shown in Table 5.

(Comparative Example 1)
To 1,400 mL of the stock solution having the same composition as in Example 1, 160 mL of 48 mass% NaOH was added as a neutralization step, and filtration was performed using a filter press.
The filtrate composition after neutralization is as shown in Table 3. A neutralization residue containing Sn and Pb was generated.

<Neutralized filtrate composition>

Next, zinc (Zn) powder was added to the filtrate after neutralization, and a substitution treatment was performed. The temperature at this time was 55 ° C., and the amount of zinc (Zn) powder added was 1.8 equivalents (49 g) with respect to indium (In). The reaction principle is as shown in the following reaction formula.
<Reaction formula>
In ₂ (SO ₄ ) ₃ + 3Zn (powder) → 3ZnSO ₄ + 2In

The filtrate composition after the substitution treatment is shown in Table 4 and FIG.
<Filtration composition after substitution treatment>

From the results shown in Table 4 and FIG. 2, the germanium (Ge) concentration decreased from 393 mg / L to 213 mg / L, and 46% of germanium was recovered (mixed in sponge-like indium metal).
Moreover, germanium can be collect | recovered in the state of an oxide from the residue which leached indium by hydrochloric acid leaching about the deposit of the substitution process obtained in the comparative example 1. When electrolytic recovery of indium was performed from the hydrochloric acid leaching solution, the recovery rate of indium calculated from the concentration of indium in the liquid before and after electrolytic recovery was 95%. The results of the recovery rates of germanium and indium are shown in Table 5.

表５の結果より、実施例１においてもインジウムの電解回収への悪影響は無いことがわかった。また、原液からインジウム電解回収前の塩酸浸出までのインジウムの回収率も、実施例１と比較例１とでは差が無いので、実施例１では、インジウムの回収率を低下させることなく、ゲルマニウムを高収率で回収できる。

From the results of Table 5, it was found that Example 1 also had no adverse effect on the electrolytic recovery of indium. Moreover, since there is no difference between Example 1 and Comparative Example 1 in the recovery rate of indium from the stock solution to hydrochloric acid leaching before indium electrolysis recovery, in Example 1, germanium was used without reducing the recovery rate of indium. It can be recovered in high yield.

(Comparative Example 2)
Germanium that could not be recovered in Comparative Example 1 was recovered by adding NaSH and H ₂ SO ₄ to the liquid after the substitution treatment of Comparative Example 1 and performing sulfidation in the same manner as in Example 1. As a result, in Comparative Example 2, not only the number of steps increased, but there was a risk that dissolved H ₂ S remained in the filtrate and harmful H ₂ S gas was generated. Moreover, since the recovery of germanium is distributed to the germanium dioxide recovered in Comparative Example 1 and the germanium dioxide obtained through oxidation leaching or the like, the two solids must be processed. Has become worse.

(Example 2)
<Influence of temperature>
Except for changing the temperature range from 30 ° C. to 80 ° C. with a set temperature of 30 ° C. to 80 ° C. with respect to 1,400 mL of the stock solution having the composition of Table 6 below, 40 mL of 15% by mass sodium hydrosulfide and 40 mL of 24% by mass sulfuric acid. The effect of temperature was tested in the same manner as in Example 1. The results are shown in Table 7 and FIG.

表７の結果から、温度が低いほど、ゲルマニウム（Ｇｅ）濃度は下がることがわかった。

From the results in Table 7, it was found that the lower the temperature, the lower the germanium (Ge) concentration.

(Example 3)
<Influence of Cd concentration>
With respect to 1,400 mL of the stock solution having the composition shown in Table 8 below, 15 mass% sodium hydrosulfide is 40 mL, 24 mass% sulfuric acid is 40 mL, and Cd is added to change the Cd concentration to 740 mg / L and 1740 mg / L. The effect of Cd concentration was tested in the same manner as in Example 1 except that the temperature was 50 ° C. and 70 ° C. The results are shown in Table 9.

表９の結果から、Ｃｄ濃度が上がると、ゲルマニウム（Ｇｅ）濃度は下がることがわかった。即ち、原液のＣｄ濃度は高いほどゲルマニウム硫化工程でのゲルマニウムの硫化物への分配率は上がるため、ゲルマニウムの回収工程及びインジウムの回収工程内で分離されるＣｄ（Ｃｄ含有液）を、原液の製造に再利用してＣｄ濃度を調整することがよいことが分かった。

From the results of Table 9, it was found that the germanium (Ge) concentration decreased as the Cd concentration increased. That is, the higher the Cd concentration of the stock solution, the higher the distribution ratio of germanium to sulfides in the germanium sulfide process. Therefore, Cd (Cd-containing solution) separated in the germanium recovery step and indium recovery step is converted into It has been found that it is better to adjust the Cd concentration by reuse in production.

Example 4
<Influence of free sulfuric acid (FA) concentration>
With respect to 1,400 mL of the stock solution having the same composition as in Example 2, 15% by mass of sodium hydrosulfide was adjusted to 40 mL, sulfuric acid and NaOH were appropriately added to change the concentration of free sulfuric acid (FA), and the temperature was set to 40 ° C. Except for the above, the effect of free sulfuric acid (FA) concentration was tested in the same manner as in Example 1. The results are shown in Table 10.

表１０の結果から、遊離硫酸（ＦＡ）濃度が３５ｇ／Ｌの時に、最もゲルマニウム（Ｇｅ）濃度が低くなった。遊離硫酸（ＦＡ）濃度が低すぎると、他の不純物が落ちやすく（硫化沈殿しやすく）なり、ゲルマニウム（Ｇｅ）濃度が低くならないと考えられる。

From the results shown in Table 10, the germanium (Ge) concentration was lowest when the free sulfuric acid (FA) concentration was 35 g / L. If the free sulfuric acid (FA) concentration is too low, other impurities are likely to fall off (sulfidation precipitation is likely), and the germanium (Ge) concentration is not likely to be low.

(Example 5 and Comparative Example 3)
Into a 1,400 mL stock solution having the same composition as in Example 2 in a thermostatic bath, 40 mL of 15% by mass sodium hydrosulfide was mixed with 40 mL of 24% by mass sulfuric acid (15% by mass sodium hydrosulfide ( NaSH) and 24 wt% sulfuric acid at a mixing mass ratio of 1: 1 (Example 5)) and 24 wt% sulfuric acid not mixed at all (15 wt% sodium hydrosulfide (NaSH) and 24 A mixing mass ratio of 1% to 0% by mass of sulfuric acid (Comparative Example 3)) was added at an addition rate of 0.5 mL / min. The temperature of the thermostatic bath was 40 ° C. After sulfurization, filtration was performed using a filter press to obtain a filtrate and germanium sulfide. The germanium (Ge) concentration in the filtrate was measured using ICP emission spectroscopy. The results are shown in Table 11.
In the filter press, 5C filter paper (φ125 mm) was used for solid-liquid separation at 4.2 kgf, and the time (seconds) when 500 mL was passed from the start of filtration was measured as the number of filtration seconds. The filtration time of Example 5 was 44 seconds, and the filtration time of Comparative Example 3 was 146 seconds. Filterability was evaluated based on the following criteria. The results are shown in Table 11.
[Evaluation criteria for filterability]
◯: Filtration time is less than 60 seconds Δ: Filtration time is 60 seconds to 120 seconds X: Filtration time is over 120 seconds

表１１の結果から、比較例３のように硫酸を添加していない場合には、溶液中にゲルマニウム（Ｇｅ）が残りやすくなるだけでなく、硫化後のフィルタープレスでのろ過性が悪く、生産性が悪化するため、水硫化ナトリウム（ＮａＳＨ）と硫酸とを併用することが必要であることがわかった。

From the results of Table 11, when sulfuric acid is not added as in Comparative Example 3, not only germanium (Ge) is likely to remain in the solution, but also the filterability with a filter press after sulfidation is poor, resulting in production. It was found that it was necessary to use sodium hydrosulfide (NaSH) and sulfuric acid together because the properties deteriorated.

Examples of the aspect of the present invention include the following.
<1> A method for recovering germanium, comprising a germanium sulfide process in which sodium hydrosulfide and sulfuric acid are added to a solution containing germanium to recover germanium as a sulfide.
<2> The method for recovering germanium according to <1>, wherein the solution containing germanium includes indium and cadmium, and includes a step of recovering indium from the solution after the sulfide is recovered in the germanium sulfide step. It is.
<3> The germanium recovery method according to any one of <1> to <2>, wherein the germanium sulfide step is performed at a temperature of 30 ° C to 70 ° C.
<4> The method for recovering germanium according to any one of <1> to <3>, wherein a free sulfuric acid (FA) concentration in the germanium sulfiding step is 20 g / L to 100 g / L.
<5> The germanium recovery method according to any one of <1> to <4>, wherein the germanium-containing solution is a solution obtained by acid leaching of an intermediate product in zinc smelting.

  The germanium recovery method of the present invention is capable of recovering high-quality germanium efficiently and inexpensively at a high recovery rate. Therefore, development of materials for so-called high-tech industries such as optical fibers and solar cells, polymerization promotion catalyst for polyethylene terephthalate resin It is preferably used as a method for recovering germanium that can be used for semiconductor elements such as diodes and transistors, electronic materials such as phase change magnetic disk materials, catalysts, and other raw materials for processing.

Claims (5)

To a solution containing germanium in addition a mixture of sodium hydrosulfide and sulfuric acid, a method of recovering germanium, which comprises germanium sulfide recovering germanium as a sulfide.   2. The method for recovering germanium according to claim 1, wherein the solution containing germanium includes indium and cadmium, and includes a step of recovering indium from the solution after the sulfide is recovered in the germanium sulfide step.   The method for recovering germanium according to claim 1, wherein the germanium sulfiding step is performed at a temperature of 30 ° C. to 70 ° C. 3.   The method for recovering germanium according to any one of claims 1 to 3, wherein a free sulfuric acid (FA) concentration in the germanium sulfiding step is 20 g / L to 100 g / L.   The method for recovering germanium according to any one of claims 1 to 4, wherein the solution containing germanium is a solution obtained by acid leaching of an intermediate product in zinc smelting.

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