JP2022079253A - Method for analyzing useful minerals included in ore - Google Patents

Abstract

To provide a method which can be applied, for example, as a method for ore concentration processing test, and with which, regarding an ore that includes useful minerals and unnecessary and gangue minerals other than those, it is possible to effectively and efficiently analyze the abundance ratio of useful minerals included in the ore.SOLUTION: The present invention is a method for analyzing the abundance ratio of useful minerals, with analysis conducted on ore concentration processing products obtained from an ore that includes translucent useful minerals, transparent unnecessary minerals, and gangue minerals. The method comprises: a step for embedding ore concentration processing products in a resin for microscopic observation and creating a sample for microscopic observation; and a step for observing the sample for microscopic observation using an optical microscope and analyzing the abundance ratio of useful minerals from the obtained observation image. In the step to analyze, the dark field and the light field images observed by the optical microscope are loaded into an image analysis device, and a total area of portions in each of the dark field and the light field images that are indicated by brightness of a prescribed threshold is compared.SELECTED DRAWING: Figure 1

Description

The present invention is a method for analyzing useful minerals contained in ore, and relates to a method for effectively and efficiently analyzing the abundance ratio of useful minerals.

In addition to useful minerals (minerals that contain a large amount of target metal in the vein), the ore mined from the mine contains a large amount of unnecessary minerals (minerals that contain almost no target metal) and gangue minerals other than the vein. There is.

Mineral processing is the first treatment for mined ore. Mineral processing means that useful minerals, waste minerals, and gangue minerals are crushed with the aim of forming a single particle, and are made into a mixture of various minerals. It is a process of separating concentrate (powdered product with a high proportion of useful minerals) and tail ore (powdered product as waste residue) by utilizing physical properties such as wettability.

Of the flotation, in the flotation, water is added to the powder and granules of the mixture obtained after crushing the ore to make a mineral slurry, which is wetted by the addition of an additive (flotation agent), the introduction of bubbles, and the operation of stirring. It is recovered as flotation (fine ore) by adhering low particles to bubbles and floating them. On the other hand, highly wet particles are settled and separated as sedimentation (tailings). Further, in the flotation beneficiation, a multi-stage treatment is usually performed, for example, a treatment such as supplying the flotation obtained in the first stage to the second stage is performed.

The operating conditions for flotation include a large number of parameters such as crushed particle size, timing of additive selection and addition, bubble size and flow rate, and appropriate number of stages. In flotation, tests are conducted to determine the conditions for beneficiation that can be separated most efficiently, and in the tests, useful minerals, waste minerals, and gangue in the concentrate or tailing obtained as flotation products. It is important to measure the abundance ratio of minerals. Among them, it is particularly important to measure at least the abundance ratio of useful minerals.

For example, it is possible to confirm the metal composition to be recovered by chemically analyzing the concentrate, but since the mineral processing is a physical separation process as described above, the mineral processing conditions can be determined only by the chemical analysis results. It's difficult to determine. At the same time, it was also necessary to confirm the separation status of the target particles by observing the concentrate powder under a microscope by a skilled worker.

On the other hand, the Mineral Liberation Analyzer (MLA), which has become popular in recent years, is a device that analyzes the type, particle size, and bonding state of minerals contained in ore, and can be obtained in various mineral processing tests. By analyzing the weight and grade of the products in combination, it is possible to understand how the mineral particles in various products are separated by the mineral processing test.

As a known technique, for example, Patent Document 1 discloses a method of embedding a mineral sample in a resin and visually observing it with an optical microscope when quantitatively analyzing the distribution of a mineral containing a metal or an oxide component. Further, in Patent Document 2, by applying a predetermined embedding method for mineral powder particles as a method for preparing an observation sample for MLA analysis, the bias of the presence state of minerals due to the difference in specific gravity of ore particles is described. The method of observation is disclosed.

Japanese Unexamined Patent Publication No. 2004-347330 Japanese Unexamined Patent Publication No. 2016-050918

However, when the method disclosed in Patent Document 1 is applied to measure at least the abundance ratio of useful minerals in the flotation test, it is difficult to improve the measurement accuracy because visual microscopic observation is required. rice field. In addition, as described above, when the basic technique is applied, chemical analysis is required, which not only takes a certain amount of time, but also requires analysis and observation by skilled workers, which is efficient. I couldn't make a good measurement.

By applying the MLA device, the efficiency is improved as compared with the chemical analysis, and the analysis observation by a skilled worker becomes unnecessary, so that the measurement accuracy can be improved.

However, although it is possible to shorten the required time compared to chemical analysis, for example, when the useful mineral is an opaque mineral and the unnecessary mineral and the gangue mineral are known to be transparent minerals. In many cases, it is over-spec to measure with an MLA device. That is, it is not necessary to analyze the type, particle size, and bonding state of the minerals contained in the ore, which reduces the processing capacity of the MLA apparatus.

In addition, since the MLA device is a mineral analyzer based on a scanning electron microscope equipped with an energy dispersive X-ray analyzer, it is difficult to place it at each operation site, and it is limited to the analysis department equipped with analysis equipment. Generally, the number of units is arranged.

The present invention has been proposed in view of such circumstances, and can be applied, for example, as a method for a mineral processing test, and is intended for ores containing useful minerals and other unnecessary minerals and gangue minerals. , It is an object of the present invention to provide a method capable of effectively and efficiently analyzing the abundance ratio of effective minerals contained in the ore.

The present inventor has made extensive studies to solve the above-mentioned problems. As a result, by observing ores containing useful minerals, which are opaque minerals, and unnecessary minerals and vein stone minerals, which are transparent minerals, with an optical microscope, dark-field images and bright-field images can be obtained. It was found that useful minerals can be recognized in dark-field images, and unnecessary minerals and ore minerals can be recognized in bright-field images. Then, they found that the abundance ratio of useful minerals could be efficiently analyzed by calculating the area ratio of each mineral from those images, and completed the present invention.

(1) The first invention of the present invention is a beneficiation treatment product obtained from an ore containing a useful mineral which is an opaque mineral (opaque mineral) and a waste mineral and a vein stone mineral which are transparent minerals (transparent mineral). Is a method of analyzing the abundance ratio of useful minerals contained in the beneficiation treatment product, and the beneficiation treatment product to be analyzed is embedded in a resin for microscopic observation, mirror-polished, and then mirror-polished. A sample preparation step for preparing a sample for microscopic observation, and an analysis step for observing the microscopic observation sample using an optical microscope and analyzing the abundance ratio of the useful mineral with an image analyzer based on the obtained observation image. In the analysis step, the dark field image observed by the optical microscope and the bright field image observed by the optical microscope are taken into the image analysis device, and the dark field image is captured by the image analysis device. This is an analysis method for comparing the total area of the portions indicated by the brightness of a predetermined threshold in each of the field image and the bright field image.

(2) In the second invention of the present invention, in the first invention, the portion indicated by the predetermined threshold brightness in the dark field image indicates the transparent mineral, and the bright field image shows the predetermined threshold brightness. The part shown indicates the opaque mineral, and in the analysis step, the abundance ratio of the useful mineral is determined by the image analyzer based on the ratio of the total area of the dark-field image and the bright-field image. It is an analysis method to calculate.

According to the present invention, the abundance ratio of useful minerals contained in ore can be effectively and efficiently analyzed without using an MLA apparatus as in the prior art.

It is a photographic figure of a dark field image obtained by observing with an optical microscope. It is a photographic figure of a bright-field image obtained by observing with an optical microscope. It is a photograph figure of the analysis image by the MLA apparatus.

Hereinafter, a specific embodiment of the present invention (hereinafter, also referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments, and can be carried out with appropriate modifications without changing the gist of the present invention.

In the analysis method according to the present embodiment, a mineral processing product obtained by subjecting an ore containing useful minerals, unnecessary minerals and gangue minerals to a mineral processing such as flotation is included in the mineral processing product. This is a method for analyzing the abundance ratio (ratio) of useful minerals.

As described above, in the beneficiation treatment such as flotation, there are many parameters such as pulverization particle size, selection and addition timing of additives, bubble size and flow rate, and appropriate number of stages. In the mineral processing, conditions that enable the most efficient separation of concentrates (granular products with a high proportion of useful minerals) and taillings (granular products as waste residues) (mineral processing conditions). Must be confirmed and set in advance. Then, a mineral processing test is conducted to investigate the mineral processing conditions. In the mineral processing test, it is important to measure the abundance ratio of useful minerals, waste minerals, and gangue minerals in the concentrate or tailing obtained as a flotation product (mineral processing product).

According to the analysis method according to the present embodiment, it can be applied to the method in the mineral processing test, the abundance ratio of useful minerals can be effectively analyzed, and it contributes to appropriate setting of the mineral processing conditions of various parameters. .. In addition, since the analysis that was conventionally performed using the mineral particle analysis device (MLA device) can be performed using a relatively simple device called an optical microscope, on-site analysis is also possible, and it is operational. It is possible to perform highly efficient analysis both economically and economically.

Here, the "useful mineral" refers to a mineral containing a desired metal (target metal) among the vein minerals. Further, the "unused mineral" refers to a mineral containing almost no target metal among the vein minerals, as opposed to a useful mineral. Further, the "gangue mineral" is a mineral that is not a vein mineral and does not contain a target metal.

Further, in this analysis method, useful minerals are opaque minerals (hereinafter, also referred to as "opaque minerals"), and unnecessary minerals and vein stone minerals (minerals other than useful minerals) are transparent minerals (hereinafter, "transparent minerals"). ”), Which is particularly suitable.

Specifically, the analysis method according to the present embodiment is obtained by observing a sample preparation step for preparing a sample for microscopic observation from a beneficiation treatment product to be analyzed and the sample for microscopic observation using an optical microscope. It has an analysis step of analyzing the abundance ratio of useful minerals based on the observed image.

[Sample preparation process]
In the sample preparation step, the beneficiation treatment product to be analyzed is embedded in a resin for microscopic observation and mirror-polished to prepare a sample for microscopic observation.

Here, the "mineral processing product" to be analyzed is a processed product (granular ore) obtained by performing a mineral processing such as flotation under arbitrary conditions, and even if it is a concentrate, it is a tailing ore. May be. As described above, the analysis method according to the present embodiment can be preferably applied to a mineral processing test for confirming and setting the optimum mineral processing conditions for efficiently separating the concentrate and the tailling. For example, the Tailings, which is a mineral processing product, is observed using an optical microscope in the analysis step described later, and the abundance ratio of useful minerals is analyzed from the observed images to perform the analysis under arbitrary conditions. The effectiveness of the mineral processing can be judged. Specifically, when the abundance ratio of useful minerals in the Tailings to be analyzed is large, it is possible to grasp the result that the Tailings contain a large amount of useful minerals to be separated as floating ores. For example, it can be used as an index for crushing conditions of minerals, selection of additives, and adjustment of addition timing.

In the sample preparation step, the mineral processing product to be analyzed is mixed with a resin for microscopic observation and embedded in the resin. By embedding the mineral processing product in resin in this way, it is possible to immobilize the analysis target that is powdery and granular, and the cross section of the sample is easily exposed by subsequent mirror polishing to perform clear observation analysis. It becomes possible.

The resin is not particularly limited. For example, a thermosetting resin (hot resin) can be used. By embedding and fixing the mineral processing product with a thermosetting resin in this way, cutting processing is not required when observing under a microscope, and good observation analysis is possible simply by mirror polishing and exposing the cross section. Become. As the thermosetting resin, known ones can be used, and examples thereof include epoxy resin, phenol resin, acrylic resin, and diallyl resin.

The mixing amount of the resin is not particularly limited as long as it can embed the mineral processing product, and can be, for example, about 5 to 25 times the volume of the mineral processing product.

The operation of mixing the mineral processing product and the resin is to put the mineral processing product in a container such as a vial, add a resin such as a thermosetting resin to it, and mix it for a predetermined time with a mixer such as a locking mill. Can be done by.

Further, for example, when a thermosetting resin is used as the resin, the resin is cured by heat-treating the mineral processing product embedded in the resin. The heat treatment conditions (curing conditions) are preferably set appropriately according to the type of the thermosetting resin to be used, and the heat treatment is performed at a heating temperature equal to or higher than the curing temperature of the thermosetting resin. The heating time is not particularly limited, but may be a time for curing until a strength that can withstand the mechanical processing of the mirror surface polishing to be performed later is obtained, and a maximum of about 1 hour is sufficient.

In the heat treatment, the heat-curable resin is heated to a temperature lower than the curing temperature, preferably a lower temperature (for example, a temperature of about 75% of the curing temperature, preferably a temperature of about 70%), and held at that temperature for a certain period of time. After that, the treatment may be performed so as to raise the temperature to a temperature equal to or higher than the curing temperature (set heating temperature). As described above, by performing the treatment of holding the resin at a temperature lower than the curing temperature for a certain period of time, the resin can be infiltrated into the voids of the beneficiation treatment product, and a better sample for microscopic observation can be prepared.

Mirror polishing can be performed by a known method. For example, it can be performed by mechanical polishing such as buffing or polishing with abrasive paper. By polishing the predetermined surface of the sample in this way, a smooth surface (polished surface) in which the cross section of the mineral processing product (granular ore) is exposed is formed. Thereby, a sample for microscopic observation can be obtained. Then, the obtained sample for microscopic observation is subjected to the analysis step of the next step, and observation by an optical microscope and image analysis are performed on the polished surface of the sample for microscopic observation.

[Analysis process]
In the analysis step, the sample for microscopic observation is observed using an optical microscope, and the abundance ratio of useful minerals is analyzed by an image analyzer based on the obtained observation image.

Specifically, a dark-field image obtained by observation with an optical microscope and a bright-field image obtained by observation with an optical microscope are captured in an image analysis device. Then, the image analysis device compares the total area of the portion indicated by the brightness of the predetermined threshold value in each of the dark field image and the bright field image.

First, in the analysis step, a sample for microscopic observation is observed with an optical microscope, and observation images of a dark field image and a bright field image are obtained.

As described above, the analysis method according to the present embodiment targets mineral processing products obtained from ores containing useful minerals which are opaque minerals and unnecessary minerals and gangue minerals which are transparent minerals. Therefore, in an optical microscope, opaque useful minerals are observed brightly in the dark field, and transparent unnecessary minerals and gangue minerals are observed brightly in the bright field. By utilizing these properties and obtaining dark-field images and bright-field images by observation using an optical microscope, the presence of useful minerals on the observation surface of the sample for microscopic observation, and unnecessary minerals and veins other than useful minerals. The presence of stone minerals can be explicitly confirmed.

In the dark-field image and the bright-field image, a predetermined threshold brightness is set, and useful minerals, unnecessary minerals, and gangue minerals are clearly indicated by observation images based on the brightness. The setting of the brightness is not particularly limited, and it may be set so that the existence of useful minerals, which are opaque minerals, can be sufficiently confirmed in a dark field image. If it is a bright-field image, it may be set so that the existence of unnecessary minerals and gangue minerals, which are transparent minerals, can be sufficiently confirmed. Further, as will be described later, when capturing an observation image into an image analysis device, for example, in the case of a dark-field image, the range (area) where useful minerals exist, and in the case of a bright-field image, the range where unnecessary minerals and gangue minerals exist. It is preferable to set the brightness to the extent that (area) can be calculated appropriately.

Next, in the analysis step, the obtained dark-field image and bright-field image are taken into an image analysis device, respectively, and each of the dark-field image and the bright-field image has a predetermined threshold of brightness, that is, a dark field. If it is an image, compare the total area of the part where useful minerals are present, and if it is a bright-field image, compare the total area of the part where unnecessary minerals and vein stone minerals are present.

Specifically, a dark-field image showing the presence of useful minerals obtained by observation with an optical microscope is taken into an image analysis device, and a bright-field image showing the presence of unnecessary minerals and vein stone minerals is used into an image analysis device. take in. Then, in the image analysis device, the total area of the particle portions of the useful minerals specified in the image is calculated from the captured dark-field image, and similarly, the captured bright-field image is not clearly shown in the image. Calculate the total area of the particle parts of minerals and gangue minerals. As a result, the abundance ratio of useful minerals on the observation surface of the sample for microscopic observation and the abundance ratios of unnecessary minerals and gangue minerals are quantitatively calculated as numerical values.

In this way, by calculating the area of useful minerals in the dark-field image and the areas of unnecessary minerals and gangue minerals in the bright-field image in the image analysis device, for example, useful minerals and unnecessary minerals are not used based on the area ratio. The abundance ratio of minerals and gangue minerals can be calculated.

As described above, for example, when the Tailings, which is a mineral processing product, is analyzed, the abundance ratio of useful minerals can be calculated from the dark-field image and the bright-field image obtained by observation with an optical microscope. , The ratio of useful minerals to be separated as floating ore in Tailings can be properly grasped. Thereby, the conditions (mineral processing conditions) in the mineral processing process can be appropriately set.

The image analysis device is not particularly limited as long as it can analyze a microscope image, and a known image analysis device can be used. Further, the image analysis device may be incorporated in the device of the optical microscope, for example, in the form of analysis software. If the optical microscope has an image analysis device built-in, the time and effort can be reduced and the time required for analysis can be shortened.

As described in detail above, according to the analysis method according to the present embodiment, it can be effectively applied to the mineral processing test, and at least the abundance ratio of useful minerals can be effectively analyzed, and various parameters can be analyzed. Contributes to the appropriate setting of mineral processing conditions. In addition, since the analysis that was conventionally performed using the mineral particle analysis device (MLA device) can be performed using a relatively simple device called an optical microscope, on-site analysis is also possible, and it is operational. It is possible to perform highly efficient analysis both economically and economically.

Further, since the image of the microscopic observation is obtained, the same sample and the same field of view can be analyzed by the conventional MLA device, and the validity of the analysis result by the optical microscope can be confirmed. Further, even if there is a difference in the measured absolute value between the analysis method according to the present embodiment and the analysis using the conventional MLA device, the results of both are compared and a calibration curve correction is performed. can do.

In addition, in order to analyze the mineral processing product and search for the mineral processing conditions, that is, in the mineral processing test, the value obtained by the analysis method according to the present embodiment (the abundance ratio of useful minerals) and the analysis value by the MLA apparatus are used. Differences in results do not pose a major problem. It is important to obtain a numerical value of the abundance ratio of useful minerals for the degree of mineral separation, and it can also be used as an index of whether the degree of separation due to mineral processing changes when the mineral processing conditions are changed. be.

Hereinafter, examples of the present invention will be described in more detail, but the present invention is not limited to the following examples.

[Example 1]
(About the analysis target)
As the sample powder to be analyzed, ore in which useful minerals are opaque minerals and unnecessary minerals and gangue minerals are transparent minerals are crushed to a particle size of 100 μm (P80) and flotated. It was subjected to treatment, and the powder of the flotation product, which was the flotation product, was recovered and used. The useful minerals were chalcopyrite (opaque minerals mainly composed of copper sulfide minerals), and the unnecessary minerals and vein stone minerals were minerals mainly composed of oxidized minerals such as alumina and silica (transparent minerals). ..

(Sample preparation process)
The dried sample powder (mineral processing product) was weighed 0.5 cc with a measuring spoon and tapped lightly for about 5 minutes with a spatula to crush the weak agglomerates generated during drying. Subsequently, the crushed powder mixture is placed in a polypropylene vial, a phenolic thermosetting resin (Bakelite PR50252, manufactured by Sumitomo Bakelite) is added, and a locking mill (RM-05, Seiwa Giken Co., Ltd.) is added. The sample powder was embedded in the resin by mixing for 10 minutes.

The sample powder embedded in the resin was heat-treated to cure the resin. For the heat treatment, a pressure heating device (CitoPress-20, manufactured by Marumoto Struas Co., Ltd.) is used, the temperature is raised to 90 ° C. and held for 4 minutes, then heated to 180 ° C. and held under a pressure of 75 bar for 5 minutes. I went by that. Then, the observation surface of the sample was polished and mirror-finished to obtain a sample for microscopic observation.

(Analysis process)
Next, the microscope observation sample was observed with an optical microscope (microscope VHX-6000, manufactured by KEYENCE CORPORATION) at a magnification of 300 times, and a dark-field image and a bright-field image were obtained. FIG. 1 is a photographic diagram of a dark-field image, (A) is a photographic diagram showing particles of a useful mineral which is an opaque mineral with a brightness of a predetermined threshold, and (B) is a photographic diagram of the useful mineral of (A). It is a photograph figure which colored the part of a particle. Further, FIG. 2 is a photographic diagram of a bright-field image, (A) is a photographic diagram in which particles of unnecessary minerals and vein stone minerals, which are transparent minerals, are clearly shown at a predetermined threshold of brightness, and (B) is (B). It is a photograph figure which colored the part of the particle of the useless mineral and the vein stone mineral of A).

Subsequently, the obtained dark-field image and bright-field image are taken into an image analysis device (image analysis software (WinROOF2018, PC equipped with Mitani Shoji Co., Ltd.)), and the area value of the particles obtained in each image is calculated. Based on the area values of the particles in the dark-field image and the area values of the particles in the bright-field image, the abundance ratios of useful minerals, which are opaque minerals, and unnecessary minerals and vein stone minerals, which are transparent minerals, were calculated.

As a result, it was found that the abundance ratio of useful minerals was 24%.

[Reference Example 1]
As Reference Example 1, the abundance ratio of useful minerals was analyzed by a mineral particle analyzer (Mineral Liberation Analyzer, MLA apparatus) in the same field of view using the same sample. FIG. 3 is a photographic diagram showing an analysis image by the MLA apparatus.

As a result of the analysis, it was found that the abundance ratio of useful minerals was 33%.

From the results of Example 1 and Reference Example 1, the abundance ratio of the useful mineral obtained by the analysis method of Example 1 is different from the ratio by the analysis by the MLA device (result of Reference Example 1). However, the difference is about 10% when compared with the absolute value of the calculated area, and the difference can be reduced by comparing the results regularly and making a calibration curve correction, which is an effective analysis result. I was able to judge that.

Claims (2)

Mineral processing products obtained from ores containing useful minerals that are opaque minerals (opaque minerals) and unnecessary minerals and vein stone minerals that are transparent minerals (transparent minerals) are included in the beneficiation treatment products. It is a method to analyze the abundance ratio of useful minerals.
A sample preparation step of embedding the beneficiation treatment product to be analyzed in a resin for microscopic observation and mirror polishing to prepare a sample for microscopic observation.
It has an analysis step of observing the sample for microscopic observation using an optical microscope and analyzing the abundance ratio of the useful mineral by an image analyzer based on the obtained observation image.
In the analysis step,
The dark-field image observed by the optical microscope and the bright-field image observed by the optical microscope are captured in the image analyzer, respectively.
The image analysis apparatus compares the total area of the portions indicated by the brightness of a predetermined threshold between the dark field image and the bright field image.
Analytical method. The portion of the dark-field image indicated by the brightness of the predetermined threshold indicates the transparent mineral, and the portion of the bright-field image indicated by the brightness of the predetermined threshold indicates the opaque mineral.
In the analysis step,
The image analysis apparatus calculates the abundance ratio of the useful mineral based on the ratio of the total area of the dark-field image and the bright-field image.
The analysis method according to claim 1.

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