Analytical methods for mineral leachability

Abstract

The present application provides a method for analyzing the leachability of minerals, which belongs to the field of process mineralogy. The method comprises the following steps: taking a sample to be tested, crushing it, enriching it, and selecting single mineral particles to obtain target mineral particles; applying epoxy resin glue to a sample preparation abrasive, adding target mineral particles, and subjecting it to curing and grinding to obtain a primary sample; cutting the primary sample, placing it with the grinding surface facing downwards on the bottom of the sample preparation abrasive along with three pieces of wear-resistant alloy, injecting epoxy resin glue to cure it to form a composite sample, performing a first automatic mineralogical analysis after fine grinding and polishing, and carbon spraying, and measuring the target mineral area; performing a leaching treatment after cleaning, and obtaining a treated sample; performing a second automatic mineralogical analysis after curing, fine grinding and polishing, and carbon spraying, and measuring the residual target mineral area and calculating the target mineral leachability index. The present application provides reliable technical support for the optimization of mineral processing technology and resource assessment, and is particularly suitable for the development of efficient leaching processes for precious metals, rare earths, and the like.

Description

Technical Field

[0001] The invention relates to the technical field of process mineralogy, and in particular to a method for analyzing the leachability of minerals. Background Art

[0002] Mineral leachability analysis, a core technology in hydrometallurgy and mineral processing, plays a key role in low-grade ore development, tailings resource utilization, and rare metal extraction through selective dissolution methods such as chemical leaching and bioleaching. With the increasing depletion of mineral resources and increasing environmental protection requirements, the need for accurate mineral leachability evaluation is becoming increasingly prominent.

[0003] Traditional assessment methods primarily rely on batch leaching tests combined with chemical elemental analysis. While these methods can generate overall leaching rate data, they suffer from significant technical limitations in practical application. First, these methods cannot distinguish between the dissolution kinetics of the target mineral and associated minerals. Second, they lack a means to quantitatively characterize the impact of mineral occurrence (such as fine-grained inclusions and complex intergrowths) on leaching efficiency, resulting in a lack of scientific evidence for process optimization at the microscale. Current technical bottlenecks in mineral leachability analysis lie in several areas: In sample preparation, conventional pulverization and classification processes can easily lead to over-pulverization or selectivity loss of the target mineral, making it difficult to ensure representativeness of the analyzed sample, particularly for ores with unevenly distributed particle sizes. Regarding characterization techniques, while surface analysis techniques such as scanning electron microscopy (SEM) and atomic force microscopy (AFM) can provide local morphological information, they are limited by the field of view and sample size, making it impossible to achieve global quantitative analysis of mineral dissolution behavior. Furthermore, the resin embedding-grinding and polishing process, a key step in pre- and post-leaching comparative analysis, currently lacks standardized control specifications. Fluctuations in factors such as embedding agent permeability and grinding and polishing parameters can introduce analytical errors.

[0004] In view of this, it is necessary to design an improved analytical method for mineral leachability to solve the above problems. Summary of the Invention

[0005] In view of the technical problems existing in the background technology, the present application provides a method for analyzing the leachability of minerals, aiming to solve the technical problems of the lack of representativeness and low accuracy of traditional mineral leachability analysis methods.

[0006] The present application provides a method for analyzing the leachability of minerals, comprising the following steps:

[0007] S1. Take the sample to be tested and crush, enrich and select single mineral particles to obtain the target mineral particles;

[0008] S2. The epoxy resin is applied to the sample preparation mold, the target mineral particles are added, and the sample is cured and ground to obtain a primary sample;

[0009] S3 cutting the primary sample, grinding surface downward and three wear-resistant alloys placed together at the bottom of the sample preparation tool, injecting epoxy resin glue to form a composite sample;

[0010] S4. The composite sample is finely ground and polished until it is flush with the surface of the wear-resistant alloy, and after carbon spraying, the first automatic mineralogy analysis is performed to measure the target mineral area S n ; n is 1, 2, 3..., indicating the target mineral type;

[0011] S5. Cleaning the surface of the sample obtained in step S4 and performing leaching treatment to obtain a treated sample;

[0012] S6. Apply epoxy resin glue to the sample preparation grinding tool, add the treated sample, inject epoxy resin glue to cure, and finely grind and polish until it is flush with the surface of the wear-resistant alloy. After carbon spraying, perform a second automatic mineralogy analysis and measure the residual target mineral area S n ';

[0013] S7. Calculate the target mineral leachability index A n , where A n = 1-S n ' / S n .

[0014] As a further improvement of the present application, in step S2, the coating thickness of the epoxy resin glue is 0.1~0.3mm.

[0015] As a further improvement of the present application, the grinding process uses 200~600 mesh grinding materials, and the grinding thickness is 0.05~0.15mm.

[0016] As a further improvement of the present application, in step S3, the wear-resistant alloy is tungsten carbide with a hardness of ≥9 Mohs, and its three-dimensional size is 1~5 mm, and the lower surfaces of the three alloys are kept horizontal and not on the same straight line.

[0017] As a further improvement of the present application, in step S3, the height of the composite sample is 0.8-1.2 cm.

[0018] As a further improvement of the present application, in step S1, the single mineral particles include one or more target mineral particles in a monomeric state, an intergrown state, and an encapsulated state.

[0019] As a further improvement of the present application, the crushing adopts a jaw crusher to reduce the particle size to 1-5 mm or a roller crusher to reduce the particle size to >0.5 mm.

[0020] As a further improvement of the present application, the fine grinding uses 1000-1400 mesh abrasives, the polishing uses abrasives with a particle size of ≤1 μm, and the polishing time is ≥5 min.

[0021] The beneficial effects of this application are:

[0022] The present application provides a method for analyzing the leachability of minerals, which comprises taking a sample to be tested and crushing, enriching and selecting single mineral particles to obtain target mineral particles; applying epoxy resin glue to a sample preparation abrasive, adding target mineral particles, and subjecting to curing and grinding treatment to obtain a primary sample; cutting the primary sample, placing the grinding surface downward together with three pieces of wear-resistant alloy at the bottom of the sample preparation abrasive, injecting epoxy resin glue to cure to form a composite sample; fine-grinding and polishing the composite sample until it is flush with the surface of the wear-resistant alloy, and performing a first automatic mineralogical analysis after carbon spraying to measure the target mineral area; cleaning the surface of the obtained sample, and performing a leaching treatment to obtain a treated sample; applying epoxy resin glue to a sample preparation abrasive, adding the treated sample, injecting epoxy resin glue to cure, fine-grinding and polishing until it is flush with the surface of the wear-resistant alloy, and performing a second automatic mineralogical analysis after carbon spraying to measure the residual target mineral area; and calculating the target mineral leachability index based on the target mineral area measured before and after leaching treatment. The present application provides reliable technical support for the optimization of mineral processing technology and resource assessment, and is particularly suitable for the development of efficient leaching processes for precious metals, rare earths, etc.

[0023] This application eliminates grinding and polishing depth errors by using a wear-resistant alloy reference and two resin fixation steps. A wear-resistant alloy (tungsten carbide) serves as a grinding and polishing end indicator, combined with a thin layer of resin adhesive technology to ensure consistent exposure of the target mineral. High-resolution scanning combined with area ratio calculations avoids the dissolution loss errors associated with traditional gravimetric methods. Automatic mineralogy (such as MLA or QEMSCAN) scanning for mineral area changes eliminates impurity interference in traditional chemical analysis, resulting in more reliable results.

[0024] This application can analyze minerals in different occurrence states (single / conjoined / inclusions) and is applicable to various mineral types such as sulfide ores and oxide ores.

[0025] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] To more clearly illustrate the technical solution of this application, the following is a brief introduction to the drawings used in this application. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be derived from these drawings without inventive effort.

[0027] Figure 1 Flow chart of the method for analyzing the leachability of minerals provided in the embodiments of the present application;

[0028] Figure 2 This is a comparison diagram of the chalcopyrite before and after treatment in the examples of this application;

[0029] Figure 3 This is a comparison diagram of the results before and after chalcocite treatment in the examples of this application. DETAILED DESCRIPTION

[0030] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0032] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0033] Traditional mineral leachability analysis methods cannot accurately distinguish the dissolution kinetics differences between target minerals and associated minerals, and it is difficult to quantitatively characterize the impact of mineral occurrence status on leaching efficiency. At the same time, there are limitations in sample preparation and characterization techniques, resulting in a lack of representativeness and accuracy in the analysis results.

[0034] In order to solve the technical problems of lack of representativeness and low accuracy of traditional mineral leachability analysis methods, the present application provides a mineral leachability analysis method, wherein, by combining a comprehensive method of special sample processing and preparation, further chemical leaching treatment and automatic mineralogical quantitative analysis, the leachable ratio of the target mineral is accurately and quantitatively evaluated, the quantitative statistics of the mineral composition and embedding characteristics are achieved, the mineral dissolution behavior during the in situ leaching process is tracked, and a quantitative correlation model of the mineral surface changes before and after leaching is established.

[0035] Please refer to Figure 1 The present invention provides a method for analyzing the leachability of minerals, comprising the following steps:

[0036] S1. Take the sample to be tested and crush, enrich and select single mineral particles to obtain the target mineral particles;

[0037] S2. Apply epoxy resin glue to the sample preparation mold, add the target mineral particles, and cure and grind to obtain a primary sample;

[0038] Specifically, according to the target mineral species, primary samples of different mineral species are prepared respectively;

[0039] S3. Cut the primary sample, place the ground surface downward with three pieces of wear-resistant alloy on the bottom of the sample preparation tool, and inject epoxy resin to cure to form a composite sample;

[0040] Specifically, multiple primary samples can be placed in the same sample preparation mold. If the number of samples is large, multiple composite samples can be prepared;

[0041] S4. The composite sample is finely ground and polished until it is flush with the wear-resistant alloy surface. After carbon spraying, the first automatic mineralogy analysis is performed to measure the target mineral area S. n ; n is 1, 2, 3..., indicating the target mineral type;

[0042] S5. Cleaning the surface of the sample obtained in step S4 and performing leaching treatment to obtain a treated sample;

[0043] S6. Apply epoxy resin glue to the sample preparation abrasive, add the treated sample, inject epoxy resin glue to cure, and fine-grind and polish until it is flush with the wear-resistant alloy surface. After carbon spraying, perform a second automatic mineralogy analysis and measure the residual target mineral area S. n ';

[0044] S7. Calculate the target mineral leachability index A n , where A n = 1-S n ' / S n .

[0045] In the technical solution of the embodiment of the present application, the sample to be tested is crushed, enriched and single mineral particles are selected to separate the target mineral particles and reduce the interference of other minerals; the mineral particles are fixed by epoxy resin glue to facilitate subsequent cutting and grinding; the height consistency after two fine grindings is controlled by wear-resistant alloy to ensure the accuracy of the data; the leaching treatment simulates the leaching conditions in actual hydrometallurgy or mineral processing to observe the dissolution of the target mineral; based on the results of two automatic mineralogical analyses, the target mineral leachability index is calculated. This index reflects the degree of solubility of the target mineral under specific leaching conditions. The larger the value, the better the leachability of the target mineral.

[0046] Furthermore, in some embodiments, in step S2, the coating thickness of the epoxy resin glue is 0.1-0.3 mm.

[0047] In the technical solution of the embodiment of the present application, the thickness of the epoxy resin glue needs to be sufficient to ensure that the target mineral particles can be firmly fixed. If it is too thick, it may affect the subsequent grinding and polishing accuracy and the exposure of the target mineral. If the resin layer is too thin, it may not provide sufficient support force, causing the mineral particles to move or be damaged during the grinding process. After adding the epoxy resin glue, the sample preparation abrasive tool is left to stand for 2 to 5 minutes, and the target mineral particles are placed. Preferably, the target mineral particles are spread flat on the surface of the epoxy resin glue to avoid overlapping or tilting. Vacuum is used to remove bubbles, and the tool is left to stand and solidify at room temperature (20 to 30°C).

[0048] Furthermore, in some embodiments, the grinding process uses 200-600 mesh grinding materials, and the grinding thickness is 0.05-0.15 mm.

[0049] In the technical solution of the embodiment of the present application, 200~600 mesh sandpaper or abrasive is preferred. During grinding, the mineral surface is exposed, and the force needs to be controlled to prevent the mineral from falling off. The degree of mineral exposure can be observed under a microscope during grinding. The grinding thickness is controlled to be 0.05~0.15mm, preferably 0.5 times the thickness of the thin layer of resin glue.

[0050] Furthermore, in some embodiments, in step S3, the wear-resistant alloy is tungsten carbide with a hardness of ≥9 Mohs, and its three-dimensional dimensions are 1-5 mm, and the lower surfaces of the three alloys are kept horizontal and not on the same straight line.

[0051] In the technical solution of the embodiment of the present application, the purpose of cutting samples is to place multiple target mineral samples in the same sample preparation tool; after cutting, the samples are placed at the bottom of the sample preparation tool, preferably, the bottom is at the same height as the lower surface of the wear-resistant alloy; the three wear-resistant alloys are preferably tungsten carbide, and the alloy serves as a height reference and grinding and polishing termination indicator. The lower surfaces of the three wear-resistant alloys are horizontal and not on the same straight line, and the three-dimensional dimensions are within the range of 1~5mm.

[0052] Furthermore, in some embodiments, in step S3, the height of the composite sample is 0.8-1.2 cm.

[0053] In the technical solution of the embodiment of the present application, the height of the composite sample needs to be moderate to facilitate operation during the subsequent grinding and polishing processes.

[0054] Furthermore, in some embodiments, in step S1 , the single mineral particle includes one or more target mineral particles in a monomeric state, an intergrown state, or an encapsulated state.

[0055] In the technical solution of the embodiment of the present application, the single mineral particle is preferably a target mineral particle in a monomeric state, and may also be a target mineral particle in an intergrown state or an encapsulated state.

[0056] Furthermore, in some embodiments, the crushing is performed using a jaw crusher to reduce the particle size to 1-5 mm or a roller crusher to reduce the particle size to >0.5 mm.

[0057] In the technical solution of the embodiment of the present application, it is preferred to use a jaw crusher for coarse crushing to reduce the particle size to 1~5mm; or a roller crusher for fine crushing to make the particle size greater than 0.5mm; it is necessary to avoid over-crushing to cause loss of target minerals; enrichment of target minerals can be carried out by gravity separation (shaking table, centrifugal separation), flotation and other means to increase the content of target minerals; selection of single mineral particles of target minerals can be carried out by manual sorting methods.

[0058] Furthermore, in some embodiments, the fine grinding uses a 1000-1400 mesh abrasive, the polishing uses a grinding material with a particle size of ≤1 μm, and the polishing time is ≥5 min.

[0059] In the technical solution of the embodiments of this application, 1200-grit sandpaper or abrasive is preferred for fine grinding, and polishing with abrasives of 1 μm or less is preferred. Polishing should last for at least 5 minutes, until the target mineral is flush with the alloy block, ensuring a smooth surface. The treated sample should be consistent with the initial polishing depth of the composite sample (error < ±0.02 mm). Leaching treatment conditions are selected based on the properties of the mineral, using an acid or alkaline leaching agent, with controlled concentration, temperature, and time.

[0060] Some specific examples are listed below. It should be noted that the examples described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used without manufacturer's indication are all commercially available conventional products.

[0061] Example

[0062] This embodiment provides a method for analyzing the leachability of minerals, which is used to analyze the leachability of copper minerals in a copper deposit:

[0063] S1. Based on the properties of the ore (relevant geological data are available), the copper minerals in this copper ore are primarily chalcopyrite and chalcocite, with very small amounts of bornite and copper oxide minerals. An analysis of the leachability of chalcopyrite and chalcocite is planned.

[0064] Take 1.0 kg of the sample to be tested and use a jaw crusher to crush it to a particle size of less than 5 mm; use gravity separation (centrifugal separation) to increase the content of the target minerals chalcopyrite and chalcocite; use manual separation to select single mineral particles of the target minerals; select single mineral particles of chalcopyrite and chalcocite, mainly select mineral particles in a monomeric state;

[0065] S2. First fixation: Apply a thin layer of epoxy resin glue to a thickness of 0.1 mm to both sample preparation abrasives. Allow to rest for 2 minutes. Target mineral particles are then placed and laid flat on the resin surface, avoiding overlap or tilting. Vacuum the sample to remove air bubbles. Allow the sample to cure at room temperature. Samples a1 and a2 are obtained, where 1 represents chalcopyrite and 2 represents chalcocite. Preliminary grinding of samples a1 and a2 using 300-grit sandpaper exposes the target minerals, removing a thickness of 0.05 mm to obtain samples b1 and b2, respectively.

[0066] S3. Cut samples b1 and b2, ground surface downward, and place them on the bottom of the sample preparation mold together with three wear-resistant alloys. The wear-resistant alloys are specifically tungsten carbide cubes with a three-dimensional size of 2 mm. The lower surfaces of the three alloys are pressed to keep them level with the cut samples and placed at the same height as the bottom of the sample preparation mold. The three wear-resistant alloys are not in the same straight line. Epoxy resin glue is added to a height of 1.10 cm, and air bubbles are removed under vacuum. The sample is cured at rest to obtain sample c.

[0067] S4. Grind sample c again and perform carbon spraying, using 1200 mesh abrasive until the target mineral is flush with the alloy block to ensure a smooth surface. Polish again, using abrasive less than 1 micron, for 5 minutes to obtain sample d. Grind and polish to the height of the tungsten carbide block. Perform automatic mineralogical analysis on sample d, scanning the area of ​​chalcopyrite and chalcocite. S1 = 130245mm 2 ; S2=17761mm 2 ;

[0068] S5. Clean the measurement surface with alcohol and then perform a leaching test. Leaching conditions: select an acidic leaching agent, H2SO4, at a concentration of 2 mol / L, based on the mineral properties, and react at room temperature for 6 hours. Wash the sample again and shake it with ethanol to remove surface adsorbents, obtaining sample e.

[0069] S6. Secondary fixation and comparison test: inject a thin layer of resin glue into the sample preparation abrasive, add sample e, and cure again to obtain sample f. Fine-grind sample f by carbon spraying, preferably using 1200-mesh abrasive, until the target mineral is flush with the alloy block, ensuring a smooth surface. Polishing is then performed, preferably using abrasive less than 1 micron, for at least 5 minutes to obtain sample g. Automatic mineralogical analysis is performed on sample g, and the target mineral areas S1' and S2' are obtained by scanning. S1' = 32507 mm 2 , S2'=874mm 2 ;like Figures 2 to 3 As shown in the figure, the single mineral particles of chalcopyrite and chalcocite become significantly smaller after leaching treatment;

[0070] S7. Calculate the mineral leachability index: A1 = 1 - S1' / S1 = 1 - 32507 / 130245 = 0.7504;

[0071] A2=1-S2' / S2=1-874 / 17761=0.9508; this indicates that chalcopyrite has medium leachability and chalcocite has good leachability.

[0072] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and any embodiments having substantially the same structure and effect as the technical concept within the scope of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the present application, any other embodiments that can be conceived by those skilled in the art and that combine some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for analyzing the leachability of minerals, characterized in that: The following steps are involved: S1. Take the sample to be tested and crush, enrich and select single mineral particles to obtain the target mineral particles; S2. The epoxy resin is applied to the sample preparation mold, the target mineral particles are added, and the sample is cured and ground to obtain a primary sample; The grinding thickness is 0.5 times the thickness of the epoxy resin glue; S3 cutting the primary sample, grinding surface downward and three wear-resistant alloys placed together on the bottom of the sample preparation tool, the lower surface of the three alloys remain horizontal and not in the same line, the epoxy resin glue is injected and cured to form a composite sample; S4. The composite sample is finely ground and polished until it is flush with the surface of the wear-resistant alloy, and after carbon spraying, the first automatic mineralogy analysis is performed to measure the target mineral area S n ; n is 1, 2, 3..., indicating the target mineral type; S5. Cleaning the surface of the sample obtained in step S4 and performing leaching treatment to obtain a treated sample; S6. Apply epoxy resin glue to the sample preparation grinding tool, add the treated sample, inject epoxy resin glue to cure, and finely grind and polish until it is flush with the surface of the wear-resistant alloy. After carbon spraying, perform a second automatic mineralogy analysis and measure the residual target mineral area S n '; S7. Calculate the target mineral leachability index A n , where A n = 1-S n ' / S n .

2. The method for analyzing mineral leachability according to claim 1, wherein: In step S2, the coating thickness of the epoxy resin glue is 0.1-0.3 mm.

3. The method for analyzing mineral leachability according to claim 2, wherein: The grinding process uses 200-600 mesh grinding materials, and the grinding thickness is 0.05-0.15 mm.

4. The method for analyzing mineral leachability according to claim 1, wherein: In step S3, the wear-resistant alloy is tungsten carbide with a hardness of ≥9 Mohs and a three-dimensional size of 1-5 mm.

5. The method for analyzing mineral leachability according to claim 1, wherein: In step S3, the height of the composite sample is 0.8-1.2 cm.

6. The method for analyzing mineral leachability according to claim 1, wherein: In step S1 , the single mineral particles include one or more target mineral particles in a single state, an intergrown state, or an encapsulated state.

7. The method for analyzing mineral leachability according to claim 6, characterized in that: The crushing adopts a jaw crusher to reduce the particle size to 1-5 mm or a roller crusher to reduce the particle size to more than 0.5 mm.

8. The method for analyzing mineral leachability according to claim 1, wherein: The fine grinding adopts 1000-1400 mesh abrasives, the polishing adopts abrasives with a particle size of ≤1 μm, and the polishing time is ≥5 min.

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