JPH05103B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for separating _and concentrating rare earth minerals, and more specifically, the present invention relates to a method for separating _and concentrating rare _earth minerals.・OH),
Barite (BaSO ₄ ), fluorite (CaF ₂ ), quartz (SiO ₂ ),
Calcite (CaCO ₃ ), Dolomite [(Ca, Mg)
CO ₃ ], apatite [Ca ₅ (PO ₄ ) ₃ (F, Cl, OH)],
The present invention relates to a method for separating and concentrating rare earth minerals at high concentrations from complex ores containing various minerals such as eridine (Na ₂ FeSi ₂ O ₅ ), amphibole, and micas. Rare earth elements are attracting attention as new materials in various fields such as glass, ceramics, alloys, electronic components, and catalysts, and demand for them continues to grow. More than 200 types of minerals containing rare earth elements are known, but the most important mineral resources among them are bastnasite, monazite [(Ln, Th, Y) PO ₄ ], and xenotime [( Ln,
Y) PO ₄ ]. As for its reserves, for example, it is estimated that there are approximately 5 million tons of bastnaesite in the Mountain Pass Mine in California, USA, and there are many minerals such as barite, calcite, quartz, etc.
It exists as a complex ore together with gangue minerals such as talc. The bastnaesite in these complex ores is finely dispersed in the ore, so in order to separate and concentrate the bastnaesite from the ore, it is necessary to continue until the amount passing through 100 meshes reaches about 96% or more. It had to be crushed and separated from the gangue minerals by a complex flotation process as described below. In other words, the typical flotation method currently in use is to maintain the pulp temperature at around 98°C, add soda ash to keep the pH at about 9.5, and add an oleic acid collector and ammonium lignosulfonate (carbonate mineral). and sulfate mineral inhibitors), and repeats one stage of rough selection and five stages of fine selection, resulting in a concentrate of approximately 63% [SHDayton: Mining
World (January 1956, pp. 43-45)]. However, if the type of gangue mineral in the raw ore is different or the grain size of the rare earth mineral is different, the operating conditions need to be readjusted, and moreover, the ore processing performance may deteriorate. Therefore, the present inventors searched for a method that could always obtain stable ore beneficiation results without being influenced by various factors on the raw ore side, but in the end, complex ores contained relatively large amounts. We came to the conclusion that it is extremely important to efficiently separate rare earth minerals from fluorite and barite, and along this line we conducted flotation experiments using various scavengers and inhibitors. Through repeated efforts, we have finally arrived at a method that can perform stable flotation at a high level. That is, the gist of the method for separating and concentrating rare earth minerals according to the present invention is to perform ore beneficiation by adding aluminum ions or an alkali silicate together with an aliphatic or aromatic sulfonate collector. The basic configuration and effects of the present invention will be explained below based on the experimental progress. In the following explanation, bastnaesite is taken up as a representative example of a rare earth mineral, but the present invention is not limited thereto, and can be similarly applied to rare earth minerals such as monazite and xenotime. I can do it. The present inventors first investigated the floating properties of bastnaesite by using four types of collectors [sodium dodecyl sulfate (SDS: C ₁₂ H ₂₅ SO ₃ Na), sodium dodecylbenzenesulfonate (SDSB:
C ₁₂ H ₂₅ C ₆ H ₄ SO ₃ Na), dodecylammonium chloride (DAC: C ₁₂ H ₂₅ NH ₃ Cl), and sodium oleate (NaOl: C ₁₇ H ₃₃ COONa)] to change the PH of the pulp. The buoyancy rate was investigated. A Halimon tube was used to measure the buoyancy rate. The results are as shown in Figure 1. Sodium dodecyl sulfate has a PH range of 1 to 5, sodium dodecylbenzenesulfonate has an acidic range, dodecyl ammonium chloride has a PH range of 8 to 12, and sodium oleate has a wide PH range of 3 to 10. It was confirmed that the buoyancy rate was high in each region. On the other hand, when similar floating tests were conducted on complex ores, it was found that sodium oleate and dodecylammonium chloride had almost no separation effect on bastnaesite, whereas sodium dodecyl sulfate and sodium dodecylbenzenesulfonate , a considerable bastnaesite separation effect is exhibited. From this experiment, it was thought that sulfonic acid-based scavengers and sulfate-based scavengers were more effective, so next we focused on pure fluorite, barite, and bastnaesite. The degree of floating was investigated when the concentration of . An example of the results is shown in Figure 2. Both fluorite and barite float in a wide pH range, but at pulp pH 3, fluorite is the easiest to float; Following this, bastnaesite is the most difficult to float. However, actual complex ores contain quartz, calcite, apatite, hematite, limonite, aegirine, amphibole, micas, etc. in addition to fluorite and barite as gangue, so these gangue minerals It is thought that it is extremely difficult to preferentially float. Therefore, we thought that it would be possible to simplify the ore processing process if we could selectively suspend bastnaesite without suspending gangue minerals, and we conducted research in the direction of suppressing gangue minerals and selectively suspending bastnasite. advanced. First, in order to clarify the suppressive effect on fluorite, which is the most easily suspended, pure fluorite was targeted, and the pulp PH:
3. Using sulfonic acid scavenger: 2.5mg/, sodium silicate: 3945mg/ as an inhibitor, and adding aluminum ions (AlCl ₃ 6H ₂ O) to this, the inhibitory effect on fluorite was investigated. . The results are shown in Figure 3, and the floating rate of fluorite starts to decrease when the aluminum chloride concentration is about 800 mg/(aluminum ion concentration: 89.2 mg/), and the aluminum chloride concentration is about 1400 mg/(aluminum ion concentration: When the amount exceeds 156 mg/), fluorite hardly floats. As is clear from the results of this experiment, even the most easily floating fluorite is sufficiently suppressed by the coexistence of aluminum ions. Therefore, a high suppressive effect on other gangue minerals is expected as well. The above was a preliminary experiment in which the inhibitory effect of aluminum ions was investigated on pure fluorite, but from a practical standpoint, it is necessary to clarify the inhibitory effect on gangue minerals in complex minerals containing many types of gangue minerals. Therefore, floating experiments were conducted using complex ores with the chemical composition shown in Table 1.

[Table] This complex ore contains bastnaesite as a rare earth mineral, fluorite, barite, calcite, hematite, limonite, apatite, aegirine, amphibole, micas, etc. as gangue minerals, and contains rare earth elements. In addition to Ce, La, Pr, and Nd, a small amount of Sm,
Contains Eu and Y. An MS-type flotation machine was used for flotation, and aluminum ions ( _AlCl3 .
A flotation test was conducted by varying the amount of 6H ₂ O) added.
The results are shown in Table 2.

[Table] As is clear from Table 2, the collector concentration is 1.0 mg/
In this case, the aluminum chloride concentration was set to 1250mg/
From 2000mg/(Aluminum ion concentration 140
mg/ to 280 mg/).
The Ce grade in the flotation concentrate (represented by Ce, which is the most abundant rare earth element) ranges from 8.22% to
This has improved to 11.73%, and bastnaesite is clearly concentrated. Furthermore, although the concentration of the collector differs, the higher the concentration of aluminum ions, the higher the Ce grade in the concentrate; in any case, the presence of amminium ions considerably improves the separation and concentration effect of bastnaesite. . Furthermore, exam No. 3 and No. 5
This is an example in which flotation was carried out under the same conditions except that the liquid temperature was changed, and the flotation efficiency was improved by increasing the liquid temperature. Next, as a result of a preliminary experiment, it was confirmed that the flotation efficiency was further improved when an appropriate amount of alkali silicate was used together with aluminum ions as an inhibitor, so this will also be explained. That is, Table 3 below shows the results of a flotation test conducted in the same manner as above, except that aluminum chloride (AlCl ₃ 6H ₂ O) and sodium silicate were used together as inhibitors. Especially when the aluminum chloride concentration is 1250 mg/(aluminum ion concentration 140
mg/), the Ce grade in the concentrate improves considerably as the sodium silicate concentration increases. However, when the aluminum chloride concentration was 2500 mg/(aluminum ion concentration 560 mg/), the Ce grade actually decreased as the sodium silicate concentration increased.

[Table] As is clear from these experiments, the effect of adding sodium silicate varies depending on the amount of aluminum ions coexisting, and when the aluminum ion concentration is relatively low, the suppressing effect is significantly promoted. In the above experimental example, ACC#845 was used as the collector and aluminum chloride 6 was used as the aluminum ion source.
Sodium silicate was used as the hydrate and alkali silicate, respectively, but it has been confirmed through experiments conducted in parallel that the following compounds can be used as the same effective substances. That is, aliphatic or aromatic sulfonates are most effective as collectors, and examples of particularly preferred ones include alkyl sulfonates (CnH _2o+1 SO ₃ Na, etc.), amidosulfonates [ CH ₃ (CH ₂ ) ₇ CH=CH (CH ₂ ) ₇ CON (CH ₃ )−
CH ₂ CH ₂ SO ₃ Na etc.], dialkyl sulfosuccinate (

Examples include aliphatic sulfonates such as [Formula], etc.; aromatic sulfonates such as alkylbenzene sulfonates (C ₁₂ H ₂₅ C ₆ H ₄ SO ₃ Na, etc.) and alkylnaphthalene sulfonates. All aluminum salts that dissociate aluminum ions in an aqueous solution can be used as the aluminum ion source, and in addition to the aluminum chloride hexahydrate, anhydrous aluminum chloride, aluminum citrate, aluminum hydroxide, and oxalic acid. Aluminum, aluminum phosphate, aluminum tartrate, potassium aluminum sulfate (potash alum), sodium aluminum sulfate,
Examples include aluminum sulfate. Examples of alkali silicate include water glass represented by (Me ₂ O)・nSiO ₂・mH ₂ O (where Me is an alkali metal) (e.g., sodium metasilicate, sodium orthosilicate, etc.), potash water glass, lithium water glass, or Mixtures of these are utilized. As mentioned above, when an aliphatic or aromatic sulfonate collector is used in combination with aluminum ion or an alkali silicate, bastnaesite in complex ores can be efficiently separated and concentrated. We have also confirmed the favorable conditions for carrying out ore beneficiation, so further explanation will be added. First, the PH of pulp is almost determined by the concentration of the scavenger and alkali silicate, but we investigated the preferred PH range based on the effect of improving the Ce grade in the concentrate and found that the range of 2 to 6 was optimal. It was confirmed that outside this range, the Ce quality tends to decrease slightly.
As for the temperature of the pulp, as explained in Table 2 above, the Ce grade can be improved by heating the pulp slightly higher than room temperature, but the effect of heating becomes obvious at 50°C or higher. However, when the temperature exceeds 90°C, the effect of improving Ce quality is saturated, and instead, problems such as a decrease in selective buoyancy and decomposition of the collecting agent appear due to accelerated adsorption of the collecting agent to other gangue minerals. , most preferably in the range of 50 to 90°C. Next, an experiment was conducted to determine the preferred concentration range of the inhibitor (especially aluminum ion) when a collector and inhibitor are used together, and the results shown in FIG. 4 were obtained. ACC #845 was used as the collector, and its concentration range was 0 to 10.5 mg/, and AlCl ₃ 6H ₂ O was used as the aluminum ion source.
is used in combination with 0 to 4000 mg/sodium silicate,
The pulp pH was 3.00 to 3.68, and the pulp temperature was 72 to 81°C. To evaluate the flotation efficiency, when the Ce grade in the feed at the rough sorting stage is (f) and the Ce grade in the flotation concentrate is (c), a c/f of 1.63 or higher is considered good. (○ mark), and those with a value less than 1.63 were considered defective (x mark). As is clear from Figure 4, as an inhibitor
The preferred concentration range when AlCl ₃ 6H ₂ O is used alone or in combination with sodium silicate is 1250 to 5000.
mg/(aluminum ion concentration 140 to 560 mg/
). The preferred concentration of the scavenger and alkali silicate differs depending on the type, but
Collection agent 0.5-4mg/degree, alkali silicate 4000
It has been confirmed in another experiment that it is preferable to use less than mg/mg. The timing of addition of each of the above reagents is not particularly limited, but it is most preferable to add aluminum ions or aluminum silicate and alkali silicate to the pulp solution to adjust the pH to a predetermined level, and then add the reagents at an appropriate time before or after heating. This was a method of ore beneficiation by adding an astringent. The present invention is roughly constructed as described above, and uses an aliphatic or aromatic sulfonate as a collector and an aluminum ion or aluminum ion and an alkali silicate as a suppressor. At the same time, it has become possible to separate and concentrate high-grade rare earth minerals in high yield from complex ores containing many gangue minerals. Next, the effects of the present invention will be explained with reference to Examples. Example 1 A complex ore containing bastnaesite was targeted, and bastnaesite was separated and concentrated by flotation in five stages of coarse selection and fine selection according to the process shown in FIG.
The sample was pulverized to 44 μm or less, and slime of 5 μm or less was removed before use. In addition, an alkyl sulfonate (ACC# 845: same as before) was used as a collector, AlCl ₃ 6H ₂ O was used as a suppressor, and flotation was carried out using an MS type flotation machine (capacity 200c.c.). This was done using The results are shown in Table 4, and the final flotation concentrate yielded high-grade bastnaesite with a Ce grade of 27.64% (total content of Ce, La, Pr, and Nd: 54.71%). Ta.

[Table] Example 2 Targeting complex ores including bastnaesite
I did a Locked Cycle Test. The sample used was one that had been finely ground to 44 μm or less and had slime of 5 μm or less removed in advance. The flotation machine is a Kyoto University style flotation machine (capacity
1750c.c.), an alkyl sulfonate (ACC#845) was used as a collector, and aluminum chloride (AlCl.6H ₂ O) and sodium silicate were used as inhibitors. The results are shown in Table 5, and in the final concentrate
We were able to obtain high-grade bastnaesite with a Ce grade of 29.69%.

【table】 [Brief explanation of drawings]

Figure 1 is a graph showing the influence of pH of various collectors on the flotation of bastnaesite, and Figure 2 is a graph showing the effect of alkyl sulfonate collectors on the flotation rate of bastnaesite, barite, and fluorite. Figure 3 is a graph showing the influence of aluminum chloride concentration on the flotation rate of fluorite. Figure 4 is a graph showing the relationship between the collector and aluminum chloride concentration on the flotation efficiency of complex ores. The graph shown in FIG. 5 is a diagram showing the selection process adopted in the example.

Claims (1)

[Claims] 1. In separating and concentrating rare earth minerals from complex ores containing rare earth minerals by flotation, beneficiation is performed by adding aluminum ions together with an aliphatic or aromatic sulfonate collector. A method for separating and concentrating rare earth minerals. 2. The method for separating and concentrating rare earth minerals according to claim 1, which comprises adding aluminum ions to the pulp, adjusting the pH to 2 to 6, and then adding a collector to perform ore beneficiation. 3. The method for separating and concentrating rare earth minerals according to claim 1 or 2, in which ore beneficiation is carried out at a pulp liquid temperature of 50 to 90°C. 4. A method for separating and concentrating rare earth minerals according to any one of claims 1 to 3, in which ore beneficiation is performed at an aluminum ion concentration of 140 to 560 mg/. 5. When separating and concentrating rare earth minerals from complex ores containing rare earth minerals by the flotation method, beneficiation is performed by adding aluminum ions and alkali silicate together with an aliphatic or aromatic sulfonate collector. A method for separating and concentrating rare earth minerals. 6 In claim 5, after adding aluminum ions and alkali silicate to the pulp, the PH
A method for separating and concentrating rare earth minerals, which adjusts the concentration to 2 to 6, and then performs beneficiation by adding a collector. 7. The method for separating and concentrating rare earth minerals according to claim 5 or 6, in which ore beneficiation is carried out at a pulp liquid temperature of 50 to 90°C. 8. A method for separating and concentrating rare earth minerals according to any one of claims 5 to 7, in which ore beneficiation is performed at an aluminum ion concentration of 140 to 560 mg/.