Method for determining the oxidation rate of silver ores

Abstract

The application discloses a silver ore oxidation rate determination method, and relates to the technical field of mineral processing and process mineralogy analysis. The determination method comprises the following steps: sample preparation and segmentation; silver grade calibration and gravity concentration enrichment to obtain products with different mineralogical characteristics; automatic mineralogical analysis to obtain the types, content and dissemination characteristics of silver minerals; chemical leaching correction coefficient determination to obtain the phase distribution of silver through ladder type chemical leaching and calculate the correction coefficient; gangue inclusion correction coefficient determination to analyze the content of residual silver and calculate the correction coefficient; and finally, based on the automatic mineralogical analysis data and the correction coefficient, the silver ore oxidation rate is calculated. Through the fusion of multiple technologies and data correction, the accuracy and reliability of the silver ore oxidation rate determination of the silver ore with low silver mineral content and uneven distribution are significantly improved, and accurate data support is provided for the development of the beneficiation process.

Description

Technical Field

[0001] This invention relates to the field of mineral processing and technological mineralogy analysis and determination technology, specifically to a method for determining the oxidation rate of silver ore. Background Technology

[0002] The oxidation rate of silver ore is a key process mineralogical parameter that determines the beneficiation process (such as flotation or cyanidation) and predicts the recovery rate. Accurate determination of the oxidation rate is crucial for process selection, reagent formulation, and prediction of final recovery and economic indicators. However, for a long time, the industry has mainly relied on traditional chemical phase analysis methods for determination. While this method is widely used, it has certain drawbacks.

[0003] Chemical phase analysis employs the selective dissolution of target minerals using different chemical solvents. By using a series of leaching agents with specific components, it attempts to extract silver in different phases, such as primary silver sulfide, secondary silver sulfide, native silver, and other states of silver, stepwise. This method is essentially an indirect inference method, and the accuracy of its analytical results is severely limited by the complexity of the ore itself. First, when silver minerals form complex symbiotic structures or fine inclusions with other minerals, selective solvents struggle to achieve ideal phase separation leaching. The target silver mineral may be densely encapsulated by carrier minerals (such as pyrite, galena, etc.), leading to cross-contamination issues. Second, chemical phase analysis provides extremely limited information. This method can only provide macroscopic, statistical elemental content data, completely failing to reveal microscopic information crucial to mineral processing. For example, key information such as the specific embedding characteristics of silver minerals (whether they are scattered granules, continuous veins, or dense disseminated structures). In recent years, automated mineralogical analysis techniques (such as MLA or QEMSCAN) have been applied. This technology combines scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) to directly observe and automatically identify light sections or mineral particles. However, applying this technology directly to the analysis of raw silver ore presents new challenges. Because silver minerals are typically present in extremely low concentrations and have highly uneven spatial distributions in raw ore, conventional area scanning of raw ore samples leads to insufficient statistical representativeness, resulting in poor reliability and reproducibility of the obtained data. Patent CN115356461A provides a method for quantitative analysis of silver minerals in oxidized silver-bearing ores, including the following steps: grinding, gravity separation, flotation, automated mineralogical analysis, data correction, and quantitative conversion. This method can accurately determine the types of silver minerals in the ore, precisely define the content of various silver minerals, and provide a stable silver grade. However, this method suffers from a technical problem: it can only accurately determine the content of silver minerals but cannot provide the key parameter of the oxidation rate of silver minerals or silver ore.

[0004] In view of this, it is necessary to study an oxidation rate determination method that can combine macroscopic chemical analysis and microscopic mineralogical information and accurately correct the measurement results, so as to provide a more accurate, reliable and comprehensive oxidation rate data support for the formulation of silver ore beneficiation process and recovery prediction, and solve the above-mentioned technical problems. Summary of the Invention

[0005] In view of the drawbacks of traditional chemical phase analysis methods, which employ selective solvent stepwise leaching and suffer from cross-phase mixing, limited information dimensions, and weak guidance, this invention provides a method for determining the oxidation rate of silver ore with a reasonable process and reliable results. While automated mineralogical analysis can provide microscopic information, its direct application to raw ore analysis suffers from insufficient statistical representativeness due to low silver mineral content and uneven distribution. This method organically combines gravity separation pre-enrichment, chemical analysis, and automated mineralogical analysis, and introduces chemical dissolution correction and gangue inclusion correction coefficients. It integrates macroscopic chemical analysis and microscopic mineralogical information, and can accurately correct the measurement results, significantly improving the accuracy and process guidance value of the results.

[0006] This invention provides a method for determining the oxidation rate of silver ore, comprising the following steps:

[0007] S1, Sample preparation and division: Representative silver ore samples are ground, mixed, and reduced in size to obtain samples;

[0008] S2, Gravity Separation and Silver Grade Determination: The sample prepared in step S1 is subjected to gravity separation to obtain gravity concentrate and gravity tailings, and the silver grade of the original ore is calculated.

[0009] S3, Stepwise gravity separation and automated mineralogical analysis: Take a sample of the same mass as in step S2 and perform at least two gravity separations to obtain at least three products with different density characteristics: first gravity separation concentrate, second gravity separation concentrate, and combined gravity separation tailings. Prepare automated mineralogical analysis samples for each product and analyze them to determine the types and contents of silver minerals, intergrowth or encapsulated minerals and their oxidation products in the silver ore samples, calculate the silver mineral metal distribution rate, and measure the proportion of silver mineral intergrowth.

[0010] S4, Determination of chemical leaching correction coefficient: The sample of the second gravity concentrate and the combined gravity tailings obtained in step S3 is subjected to step chemical leaching treatment, the silver content in the leachate is determined, and the chemical leaching correction coefficient is calculated.

[0011] S5, Determination of gangue encapsulation correction factor: The final residue after chemical leaching in step S4 is analyzed for mass and silver grade, and the gangue encapsulation correction factor is calculated.

[0012] S6, Calculation of silver ore oxidation rate: Based on the silver mineral metal distribution rate and silver mineral intergrowth ratio obtained in step S3, the chemical leaching correction coefficient calculated in step S4, and the gangue encapsulation correction coefficient calculated in step S5, the silver ore oxidation rate is calculated.

[0013] As a further improvement of the present invention, in step S6, the oxidation rate of the silver ore is denoted as Q, and its calculation formula is as follows:

[0014] Q = Σ [Ri.f×( Li.1×Dn'.f / (Dn'.f + Dn.f) + Li.2×O1 + Li.3×O2 )];

[0015] Wherein, Ri.f represents the distribution rate of silver mineral metal, i is 1, 2, 3..., representing native silver, sulfide silver, and other types of silver respectively; f is 1, 2, 3, representing the intercrystallization state of silver mineral metal sulfide, intercrystallization state of metal oxide, and intercrystallization state of gangue mineral respectively.

[0016] Dn.f and Dn'.f represent the content of intergrowth or encapsulated minerals and their oxidation products, respectively. Where n is 1, 2, 3..., representing galena, sphalerite, and chalcopyrite, respectively; n' is 1, 2, 3..., representing the corresponding oxidation products of galena, sphalerite, and chalcopyrite: lead oxide, zinc oxide, and copper oxide, respectively.

[0017] Li.1, Li.2, and Li.3 represent the crystallization ratios of the corresponding silver minerals with metal sulfides, metal oxides, and gangue minerals, respectively.

[0018] O1 represents the chemical leaching correction factor; O2 represents the gangue encapsulation correction factor.

[0019] As a further improvement of the present invention, in S3, the formula for calculating the silver mineral metal distribution rate Ri.f is:

[0020] Ri.f =te×Di.f×Di.f' / ∑(te×∑(Di.f×Di.f'));

[0021] Wherein, Di.f and Di.f' represent the types and contents of silver minerals, respectively. Wherein, i is the type of silver mineral, f is 1, 2, 3, representing the first heavy separation concentrate, the second heavy separation concentrate, and the combined heavy separation tailings, respectively, and f' is 1, 2, 3, representing the silver content of the target silver mineral in the first heavy separation concentrate, the second heavy separation concentrate, and the combined heavy separation tailings, respectively.

[0022] te represents the yield of the gravity separation product; where t1 represents the yield of the first gravity separation concentrate; t2 represents the yield of the second gravity separation concentrate; and t3 = 1 - t1 - t2 represents the yield of the combined gravity separation tailings.

[0023] As a further improvement of the present invention, in step S4, the calculation formula for the chemical leaching correction coefficient O1 is as follows:

[0024] O1 = (P1×V) / [ (m×W×ΣRi.f)×Σ(Ri.f×(Li.1+ Li.2)) ];

[0025] Wherein, P1 represents the silver content in the leachate, V represents the volume of the leachate, m represents the mass of the mixed sample, and W represents the silver grade of the original ore.

[0026] Ri.f represents the metal distribution rate of silver minerals;

[0027] Li.1 and Li.2 represent the crystallization ratio of the i-th silver mineral with metal sulfides and metal oxides, respectively.

[0028] As a further improvement of the present invention, in S5, the formula for calculating the gangue encapsulation correction coefficient O2 is as follows:

[0029] O2 = (P2×m1) / [ (m×W×ΣRi.f)×Σ(Ri.f×Li.3) ];

[0030] Where P2 is the silver grade of the residue, m1 is the mass of the residue; m represents the mass of the mixed sample, and W represents the silver grade of the original ore;

[0031] Ri.f represents the metal distribution rate of silver minerals;

[0032] Li.3 represents the ratio of silver minerals to gangue minerals in a single crystal.

[0033] As a further improvement of the present invention, in S3, the step-by-step reselection includes:

[0034] The first step is to perform a first gravity separation on the silver ore sample to separate the first gravity separation concentrate and the first gravity separation tailings.

[0035] The second step is to perform a second gravity separation on the first gravity concentrate to separate the second gravity concentrate and the second gravity tailings.

[0036] The first and second gravity separation tailings are combined into the final combined gravity separation tailings.

[0037] Therefore, the yields of the first concentrate, the second concentrate, and the combined tailings are t1, t2, and (1-t1-t2), respectively.

[0038] As a further improvement of the present invention, in step S2, the formula for calculating the silver grade W of the raw ore is:

[0039] W = t×c1 + (1 - t)×c2;

[0040] Where t is the gravity concentrate yield, c1 is the silver grade of the gravity concentrate, and c2 is the silver grade of the gravity tailings.

[0041] As a further improvement of the present invention, step S4, the step-by-step chemical leaching includes the following steps:

[0042] The first step is to leach out the carbonate and some of the oxidized silver using dilute hydrochloric acid;

[0043] The second step involves using anti-aqua regia to leach sulfides that encapsulate silver and sparingly soluble silver minerals.

[0044] The third step involves treating the residue with sodium sulfide and concentrated nitric acid to leach out the silver that is heavily encapsulated by minerals other than gangue.

[0045] As a further improvement of the present invention, the silver mineral includes at least one of native silver, argentite, argentite, and silver-bearing chalcopyrite.

[0046] Beneficial effects:

[0047] The method for determining the oxidation rate of silver ore provided by this invention constructs a comprehensive analytical system integrating "gravity separation pre-enrichment - automated mineralogical analysis - chemical leaching correction". First, gravity separation pre-enrichment is introduced to overcome the statistical representativeness problem of low-content silver minerals. Before automated mineralogical analysis, a gravity separation pre-enrichment step is added to separate the raw ore into products with different mineralogical characteristics, greatly increasing the "probability of occurrence" of low-content silver minerals in the analytical sample. This allows the subsequent automated mineralogical analysis to capture sufficient silver mineral particles within a limited scanning area, thereby obtaining key microscopic data such as mineral composition and embedding characteristics with high statistical representativeness and reliability. Second, a chemical leaching correction coefficient is established to eliminate the interference of mineral embedding on the calculation of oxidation rate. This invention does not rely entirely on chemical leaching or mineralogical analysis, but rather organically combines the two and introduces a crucial "correction coefficient". The specific approach is as follows: 1) First, the intergrowth ratio of silver minerals with different carrier minerals is accurately determined through automated mineralogical analysis; 2) Then, through a stepwise chemical leaching experiment (dilute hydrochloric acid → anti-aqua regia → nitric acid), the dissolution behavior of silver under different chemical environments is actually measured, and correction coefficients for oxide intergrowth and gangue intergrowth are calculated. These two correction coefficients quantitatively characterize the degree of influence of mineral intergrowth relationship on silver dissolution behavior. Third, a precise correlation model between microscopic intergrowth and macroscopic oxidation rate is constructed. The oxidation rate calculation model is not a simple summation of mineralogical or chemical data, but rather a deep integration of the silver mineral distribution rate, intergrowth ratio, and carrier mineral oxidation degree obtained from automated mineralogical analysis with the correction coefficients. Mineralogical data is used to define the occurrence state of silver, and chemical correction coefficients are used to quantify the oxidizability of that state. The final calculated oxidation rate includes both the oxidation state of the silver mineral itself and the actual influence of its intergrowth environment on the degree of oxidation, thus more closely reflecting the actual behavior of the ore in the actual beneficiation process, and has unprecedented precise guiding value for predicting recovery rate and guiding process flow. It possesses the following technical advantages:

[0048] 1. High representativeness: Through reselection and pre-enrichment, the statistical representativeness and accuracy of low-silver-content minerals in automated mineralogical analysis are improved.

[0049] 2. Complementary data: Chemical analysis provides accurate grade and macroscopic phase distribution, while automated mineralogical analysis provides intuitive microscopic mineralogical information. The two mutually verify each other to ensure reliable results.

[0050] 3. Strong process guidance: This method can not only provide the oxidation rate, but also provide key process mineralogical parameters such as the degree of liberation and symbiotic relationship of silver minerals, which can directly provide a basis for the design of mineral processing flow.

[0051] 4. Accurate results: Chemical leaching correction coefficient and gangue encapsulation correction coefficient were introduced, and the influence of mineral embedding on leaching was considered, making the measured oxidation rate closer to the behavior in actual production and the predicted recovery rate more accurate.

[0052] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0053] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the present invention will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0054] Figure 1 These are reflected light micrographs of the embedding characteristics of silver minerals in the ore sample provided in Embodiment 1 of the present invention (a indicates that galena (the carrier mineral of silver minerals) is replaced by iron oxide and lead oxide, that is, the edges of galena are oxidized; b indicates that silver minerals are embedded in lead oxide and gangue; c indicates that silver minerals are embedded in lead oxide, chalcopyrite and gangue; d indicates that chalcopyrite is the carrier mineral of silver minerals).

[0055] Figure 2 This is a scanning electron microscope energy dispersive spectroscopy (EDS) elemental distribution map provided in Embodiment 1 of the present invention (showing the distribution characteristics of Pb-galena [green] and Ag-argentite [red]) (a represents the backscattering image of silver minerals; b represents the EDS of major elements; c represents the scanning electron microscope (EDS) image of silver and lead elements).

[0056] Figure 3 This is a scanning electron microscope energy dispersive spectroscopy (EDS) elemental distribution map provided in Embodiment 1 of the present invention (showing the distribution characteristics of Pb-galena [blue] and Pb / O-lead oxide [gray]) (a represents the backscattering image of lead minerals; b represents the EDS of major elements; c represents the oxygen, sulfur and lead elemental scanning map).

[0057] Figure 4 This is a scanning electron microscope energy dispersive spectroscopy (SEM) composition analysis diagram provided in Embodiment 1 of the present invention (a represents the backscattering spectrum of silver minerals and other minerals; b represents the energy dispersive spectroscopy of chalcopyrite; c represents the energy dispersive spectroscopy of native silver; d represents the energy dispersive spectroscopy of galena; e represents the energy dispersive spectroscopy of quartz).

[0058] (Where, 1 represents chalcopyrite (Cu: 35.07%, S: 34.56%, Fe: 30.37%);

[0059] 2 represents native silver (Ag: 97.51%, S: 1.34%, Fe: 1.15%);

[0060] 3 represents galena (Pb: 87.75%, O: 0.23%, S: 12.02%);

[0061] 4 represents quartz (O: 55.58%, Si: 44.42%). Detailed Implementation

[0062] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0063] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the invention, are intended to cover non-exclusive inclusion.

[0064] In the description of the embodiments of this invention, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this invention, "multiple" means two or more, unless otherwise explicitly defined.

[0065] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0066] In the description of the embodiments of this invention, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0067] In the description of the embodiments of the present invention, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0068] In the description of the embodiments of the present invention, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0069] In the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0070] To address the technical problems of cross-contamination and limited information dimensions in traditional chemical phase analysis, as well as the insufficient statistical representativeness when automated mineralogical analysis is directly applied to silver ore, this invention provides a method for determining the oxidation rate of silver ore with a reasonable process and reliable results. This method organically combines gravity separation pre-enrichment, chemical analysis, and automated mineralogical analysis, and introduces chemical dissolution correction and gangue inclusion correction coefficients, significantly improving the accuracy and process guidance value of the results. First, a stepwise gravity separation pre-enrichment system is constructed. Through two gravity separations of the silver ore sample, a concentrate rich in sulfide minerals and coarse-grained native silver, a concentrate of intergrowths and oxide minerals, and tailings mainly composed of gangue are separated, enriching low-content and unevenly distributed silver minerals, greatly improving the statistical representativeness of subsequent analyses. Second, it integrates the advantages of automated mineralogical analysis and chemical analysis. Automated mineralogical analysis accurately obtains microscopic information such as silver mineral types, metal distribution, and intergrowth ratio, while chemical analysis provides macroscopic grade data. The two complement each other for verification, overcoming the limitations of single technologies. Thirdly, a dual correction coefficient is introduced. A chemical leaching correction coefficient is calculated through stepwise leaching with dilute hydrochloric acid, anti-aqua regia, sodium sulfide, and concentrated nitric acid. Simultaneously, a gangue encapsulation correction coefficient is obtained through residue analysis, fully considering the influence of mineral embedding and encapsulation states on oxidation rate determination. Fourthly, a scientific oxidation rate calculation model is established, integrating silver mineral metal distribution, crystallization ratio, correction coefficients, and the proportion of mineral oxidation products to achieve precise quantification of the oxidation rate. This invention not only solves the problem of insufficient accuracy in traditional methods but also provides process parameters such as liberation degree and symbiotic relationships, offering reliable data support for mineral processing flow selection and recovery rate prediction.

[0071] This invention provides a method for determining the oxidation rate of silver ore, comprising the following steps:

[0072] S1, Sample Preparation and Segmentation

[0073] Select representative silver ore samples of 3.0–6.0 kg and grind them in a laboratory mill, controlling the grinding fineness to be -0.074 mm (200 mesh) 100%. Then, thoroughly mix the ground samples and divide them into two portions of approximately equal mass using the standard quartering method or a trough divider, and label them as samples a1 and a2 respectively.

[0074] S2, Reselection and Silver Grade Calibration

[0075] Sample a1 was subjected to gravity separation (such as Nelson centrifuge, shaking table, spiral chute, etc.), with a gravity separation yield of t (0.5%~2.0%). The gravity separation concentrate and gravity separation tailings were denoted as sample b1 and sample b2, respectively.

[0076] The silver grade of the gravity separation concentrate b1 was analyzed in full volume, and the silver grade of the gravity separation tailings b2 was analyzed by sampling, and denoted as c1 g / t and c2 g / t, respectively.

[0077] The silver grade of a silver ore sample is denoted as W g / t, and its calculation formula is: W=t×c1+(1-t)×c2 g / t.

[0078] S3, Stepwise Reselection and Automated Mineralogical Analysis

[0079] S31, perform the first gravity separation on sample a2 to obtain the first gravity concentrate (gravity concentrate 1) and the first gravity tailings (gravity tailings 1); then, further gravity separation is performed on the first gravity concentrate (gravity concentrate 1) to obtain the second gravity concentrate (gravity concentrate 2) and the second gravity tailings (gravity tailings 2). Gravity tailings 1 and gravity tailings 2 are combined and denoted as combined gravity tailings.

[0080] te represents the yield of gravity separation products; among which, the yields of the first gravity separation concentrate (gravity separation concentrate 1), the second gravity separation concentrate (gravity separation concentrate 2), and the combined gravity separation tailings are t1 (0.1%~5.0%), t2 (3.0%~10.0%), and t3 (1-t1-t2), respectively.

[0081] The first heavy concentration concentrate (heavy concentration concentrate 1) mainly consists of dense sulfide minerals and some coarse-grained native silver.

[0082] Secondary concentrate (gravity concentrate 2): mainly consists of intergrowth minerals and medium-density oxide minerals.

[0083] Combined gravity separation tailings: mainly low-density gangue minerals and some fine-grained silver minerals.

[0084] S32, accurately weigh appropriate amounts (preferably 3~6 g) of representative samples from the first gravity concentrate (gravity concentrate 1), the second gravity concentrate (gravity concentrate 2), and the combined gravity tailings product, respectively, and prepare high-quality automated mineralogical analysis samples Ef (f is 1, 2, 3, representing gravity concentrate 1, gravity concentrate 2, and combined gravity tailings, respectively).

[0085] Then, the material composition was determined as follows: Di.f (i = 1, 2, 3..., representing native silver, sulfide silver, other types of silver, etc.), Di.f' (silver content of silver minerals), Dn.f (n = 1, 2, 3..., representing galena, sphalerite, chalcopyrite, etc., respectively), and Dn'.f (n' = 1, 2, 3..., representing the oxidation products of galena, sphalerite, chalcopyrite, etc.: lead oxide, zinc oxide, copper oxide, etc.). Note: Silver ore is an aggregate containing different types of silver minerals.

[0086] S33, calculate the silver mineral metal distribution rate Ri.f, the calculation formula is as follows:

[0087] Ri.f=te×Di.f×Di.f' / ∑(te×∑(Di.f×Di.f'))= [ te×(Di.f×Di.f') ] / [ t1×Σ(Di.f×Di.f') + t2×Σ(Di.f×Di.f') + (1-t1-t2) ×Σ(Di.f×Di.f') ];

[0088] Wherein, Di.f and Di.f' represent the silver mineral type and silver content, respectively. i is the silver mineral type, f is 1, 2, or 3, representing gravity concentrate 1, gravity concentrate 2, and combined gravity tailings, respectively, and f' is 1, 2, or 3, representing the silver content of the target silver mineral in gravity concentrate 1, gravity concentrate 2, and combined gravity tailings, respectively; te represents the gravity separation product yield; t1 represents the first gravity concentrate yield; t2 represents the second gravity concentrate yield; and t3 = 1 - t1 - t2 represents the combined gravity tailings yield.

[0089] S34, measure the intergrowth ratio of silver minerals Li.f (f is 1, 2, 3, representing the intergrowth and inclusion state of silver mineral metal sulfides, metal oxides, and gangue minerals, respectively).

[0090] S4, Determination of Chemical Leaching Correction Factor

[0091] Sampling and mixing of gravity concentrate 2 and combined gravity tailings from S3 according to the original yield ratio, with a mixed sample mass m of 50~100 g, were carried out in a stepwise chemical leaching process. The specific process is as follows:

[0092] First, the mixed sample was treated with dilute hydrochloric acid (analytical grade, volume concentration 15-20%), solid-liquid ratio 1:4, room temperature 20-30°C, stirring for 2-3 h) to dissolve carbonates, some iron oxides and silver minerals bound to them.

[0093] Then, the residue was treated with anti-aqua regia (anti-aqua regia: analytical grade, nitric acid and hydrochloric acid volume ratio 3:1), solid-liquid ratio 1:4, water bath 90~95°C, stirring reaction 2~3 h) to dissolve the silver encapsulated by sulfides and the remaining insoluble silver minerals.

[0094] Finally, for the final residue after the anti-aqua regia treatment, an excess of sodium sulfide (Na2S) solution was added (first add enough solution (0.1 mol / L Na2S solution) to completely submerge the precipitate; if the white color does not completely disappear after stirring, continue adding dropwise until the color no longer changes). The residue was then treated with concentrated nitric acid under heating conditions (nitric acid: analytical grade, solid-liquid ratio 1:2, water bath 90-95°C, stirring reaction for 1-2 h). After stirring and leaching, the residue was filtered, dried, and the silver content in the filtrate (volume VL) was determined.

[0095] In step S4, silver that can be leached by dilute hydrochloric acid and sodium sulfide is defined as "oxidized silver"; silver that can be leached by anti-aqua regia is defined as "sulfide-treated and encapsulated silver".

[0096] After chemical leaching treatment, the silver content P1 in the filtrate was analyzed, and the chemical leaching correction factor O1 was calculated using the following formula:

[0097] O1 = (P1×V) / [ (m×W×ΣRi.f)×Σ(Ri.f×(Li.1+ Li.2)) ];

[0098] Wherein, P1 represents the silver content in the leachate, V represents the volume of the leachate, m represents the mass of the mixed sample, and W represents the silver grade of the original ore.

[0099] Ri.f represents the metal distribution rate of silver minerals;

[0100] Li.1 and Li.2 represent the crystallization ratio of the i-th silver mineral with metal sulfides and metal oxides, respectively.

[0101] Note: if calculates data for samples E2 and E3; this step calculates the test data (silver mineral content and crystallization ratio) in samples E2 and E3, but does not calculate the data in E1. This corresponds to the calculation of O, which requires calculating all data for samples E1, E2 and E3.

[0102] S5, Determination of correction factor for gangue inclusions

[0103] For the slag treated in step S4 (nitric acid slag), the mass of the residue was measured as m1 g, the silver grade of the slag was analyzed as P2 g / t, and the correction factor for gangue encapsulation, O2, was calculated using the following formula:

[0104] O2 = (P2×m1) / [ (m×W×ΣRi.f)×Σ(Ri.f×Li.3) ];

[0105] Where P2 is the silver grade of the residue, m1 is the mass of the residue; m represents the mass of the mixed sample, and W represents the silver grade of the original ore;

[0106] Ri.f represents the metal distribution rate of silver minerals;

[0107] Li.3 represents the ratio of silver minerals to gangue minerals in a single crystal.

[0108] Note: if means calculates data for samples E2 and E3.

[0109] S6, Oxidation Rate Calculation

[0110] Based on the silver mineral metal distribution rate and silver mineral intergrowth ratio obtained in step S3, the chemical leaching correction coefficient O1 calculated in step S4, and the gangue inclusion correction coefficient O2 calculated in step S5, the silver ore oxidation rate Q is calculated using the following formula:

[0111] Q = Σ [ Ri.f×( Li.1×Dn'.f / (Dn'.f + Dn.f) + Li.2×O1 + Li.3×O2 )];

[0112] Wherein, Ri.f represents the distribution rate of silver mineral metal, i is 1, 2, 3..., representing native silver, sulfide silver, and other types of silver respectively; f is 1, 2, 3, representing the intergrowth and inclusion state of silver mineral metal sulfides, the intercrystallization state of metal oxides, and the intercrystallization state of gangue minerals respectively.

[0113] Dn.f and Dn'.f represent the content of intergrowth or encapsulated minerals and their oxidation products, respectively. Where n is 1, 2, 3..., representing galena, sphalerite, and chalcopyrite, respectively; n' is 1, 2, 3..., representing the corresponding oxidation products of galena, sphalerite, and chalcopyrite: lead oxide, zinc oxide, and copper oxide, respectively.

[0114] Li.1, Li.2, and Li.3 represent the crystallization ratios of the corresponding silver minerals with metal sulfides, metal oxides, and gangue minerals, respectively.

[0115] O1 represents the chemical leaching correction factor; O2 represents the gangue encapsulation correction factor.

[0116] The silver minerals include at least one of native silver, argentite, argentite, and silver-bearing chalcopyrite.

[0117] It should be noted that the above sampling quality and experimental parameter data are only implementation examples, and the parameters in specific implementations are not limited to the above data.

[0118] Example 1

[0119] Example 1 of this invention provides a method for determining the oxidation rate of silver ore, using ore samples taken from a silver mine in Luoyang, Henan Province. Please refer to... Figure 1 As shown, the ore has a low content of metal sulfides, mainly galena and sphalerite; the main metal oxides are hematite and magnetite; the main precious metal mineral is native silver; the gangue minerals are mainly plagioclase, orthoclase, and quartz, and the ore has a high oxidation rate. The silver minerals in this ore are mainly fine-grained, micro-grained, and medium-grained. The silver minerals are mainly angular, long-angular, and platy.

[0120] Figure 1 Characterizing the oxidation phenomena of silver minerals and their intercalated minerals; Figure 2 Characterizing the intercrystallization features of argentite and galena; Figure 3 Characterizing the properties of galena and its oxidation products; Figure 4 Characterizes the actual embedded state of silver minerals.

[0121] The determination method specifically includes the following steps:

[0122] S1, Sample Preparation and Segmentation

[0123] A representative silver ore sample of 6.0 kg was selected and ground in a laboratory ball mill to a fineness of -0.074 mm (200 mesh). The ground sample was thoroughly mixed and divided into two portions (3.0 kg) of approximately equal mass using a divider, which were labeled as samples a1 and a2, respectively.

[0124] S2, Reselection and Silver Grade Calibration

[0125] Sample a1 was subjected to gravity separation on a shaking table with a gravity separation yield of t=1%. The gravity separation concentrate and gravity separation tailings were denoted as sample b1 and sample b2, respectively. The silver grade of gravity separation concentrate b1 was analyzed by total analysis, and the silver grade of gravity separation tailings b2 was analyzed by sampling and denoted as c1=6344.21 g / t and c2=215.63 g / t, respectively.

[0126] If the silver grade of the silver ore sample is W g / t, the calculation formula is as follows:

[0127] W = t × c1 + (1 - t) × c2

[0128] =6344.21×1%+215.63×(1-1%)

[0129] =276.92 g / t.

[0130] S3, Stepwise Reselection and Automated Mineralogical Analysis

[0131] Sample a2 is subjected to gravity separation to obtain gravity concentrate 1 and gravity tailings 1. Gravity concentrate 1 is further subjected to gravity separation to obtain gravity concentrate 2 and gravity tailings 2. Gravity tailings 1 and gravity tailings 2 are combined and referred to as combined gravity tailings.

[0132] The yields of gravity concentrate 1, gravity concentrate 2 and gravity tailings are t1=1.44%, t2=6.14% and t3=(1-t1-t2)=92.42%, respectively.

[0133] Representative samples of 4 g each were accurately weighed from gravity concentrate 1, gravity concentrate 2, and gravity tailings products. After being inlaid with epoxy resin and polished, they were used to prepare automated mineralogical analysis samples Ef (f is 1, 2, and 3, representing gravity concentrate 1, gravity concentrate 2, and combined gravity tailings, respectively), as detailed in Table 1.

[0134] The material composition of sample Ef was determined by Di.f (i is 1, 2, 3..., representing native silver, sulfide silver, other types of silver, etc.), Di.f' (silver content of silver minerals), Dn.f (n is 1, 2, 3..., representing galena, sphalerite, chalcopyrite, etc., respectively), and Dn'.f (n' is 1, 2, 3..., representing the oxidation products of galena, sphalerite, chalcopyrite, etc.: lead oxide, zinc oxide, copper oxide, etc., respectively). Ri.f was calculated, as detailed in Table 2.

[0135] The intergrowth ratio of silver minerals, Li.f (f is 1, 2, and 3, representing the intergrowth and inclusion of silver mineral metal sulfides, metal oxides, and gangue minerals, respectively), is measured, as detailed in Table 3.

[0136] Table 1 Results of Automated Mineralogical Analysis of Material Composition (%)

[0137]

[0138] Table 2. Results of Ri.f Automated Mineralogical Analysis (%)

[0139]

[0140] Table 3. Results of automated mineralogical analysis of the degree of liberation of silver minerals (%)

[0141]

[0142] S4, Determination of Chemical Leaching Correction Factor

[0143] Samples of the gravity concentrate 2 and the combined gravity tailings from step S3 were taken and mixed according to the original yield, and 50 g of the mixed sample was taken.

[0144] First, the mixed sample was treated with dilute hydrochloric acid (analytical grade, volume concentration 15-20%), solid-liquid ratio 1:4, room temperature 20-30°C, stirring for 2-3 h) to dissolve carbonates, some iron oxides and silver minerals bound to them.

[0145] Then, the residue was treated with aqua regia (analytical grade aqua regia, hydrochloric acid to nitric acid volume ratio 3:1, solid-liquid ratio 1:4, water bath 90-95°C, stirring reaction 2-3 h) to dissolve the silver encapsulated by sulfides and the remaining insoluble silver minerals. For the final residue after aqua regia treatment, excess sodium sulfide (Na2S) solution was added, and the residue was treated with concentrated nitric acid under heating conditions (nitric acid: analytical grade, solid-liquid ratio 1:2, water bath 90-95°C, stirring reaction 1-2 h). After stirring and leaching, the residue was filtered, dried, and the silver content in the filtrate (5 L) was determined.

[0146] The silver content of the filtrate, P1, is 80.22 × 10⁻⁶. -6 g / L;

[0147] The correction factor O1 is calculated using the following formula:

[0148] O1 = (P1×V) / [ (m×W×ΣRi.f)×Σ(Ri.f×(Li.1+ Li.2)) ]

[0149] =(80.2210 -6 g / L5L) / (50 g×276.92g / t×(11.09%+3.25%+……7.84%)×(11.09%×(6.44%+2.59%)+3.25%×(6.47%+4.56%)+……7.84%))

[0150] =6.11523 / 6.60445

[0151] =1.08.

[0152] S5, Determination of correction factor for gangue inclusions

[0153] For the residue (nitric acid residue) treated in step S4, the residue mass m2 = 43.18 g;

[0154] Analysis showed that the silver grade in the slag was P2 = 401.40 g / t;

[0155] The correction factor O2 is calculated using the following formula:

[0156] O2 = (P2×m1) / [ (m×W×ΣRi.f)×Σ(Ri.f×Li.3) ]

[0157] =(401.3991 g / t ×43.18 g) / (50 g×276.92g / t ×(11.09%+3.25%+……7.84%)×(11.09%×5.14%+3.25%×6.24%+……7.84%×4.66%))

[0158] =2.6426 / 2.3595

[0159] =1.12.

[0160] S6, Calculate the oxidation rate Q of silver ore.

[0161] The calculation formula is as follows:

[0162] Q = Σ [ Ri.f×( Li.1×Dn'.f / (Dn'.f + Dn.f) + Li.2×O1 + Li.3×O2 ) ]

[0163] =(3.59%×((10.23%×0.1294)+(5.54%×1.08)+(4.87%×1.12)+……)+4.47%×((28.67%×0.2828)+……))

[0164] =10.39%.

[0165] The silver ore oxidation rate calculated in Example 1 of this invention was verified by flotation test and was close to the test index, providing good guidance.

[0166] In summary, this invention discloses a method for determining the oxidation rate of silver ore, relating to the field of mineral processing and technological mineral analysis technology. The method includes: sample preparation and segmentation; silver grade calibration and gravity concentration to obtain products with different mineralogical characteristics; automated mineralogical analysis to obtain the types, contents, and distribution characteristics of silver minerals; determination of chemical leaching correction coefficients, obtaining the phase distribution of silver through stepwise chemical leaching and calculating correction coefficients; determination of gangue inclusion correction coefficients, analyzing the silver content in the residue and calculating correction coefficients; and finally, calculation of the silver ore oxidation rate based on the automated mineralogical analysis data and correction coefficients. This invention, through the integration of multiple technologies and data correction, significantly improves the accuracy and reliability of determining the oxidation rate of silver ores with low and unevenly distributed silver mineral content, providing precise data support for the formulation of mineral processing technologies.

[0167] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A method for determining the oxidation rate of a silver ore, characterized by, The method comprises the following steps: S1, sample preparation and division: grinding, mixing and dividing a representative silver ore sample to obtain a sample; S2, gravity separation and silver grade calibration: performing gravity separation on the sample prepared in step S1 to obtain gravity separation concentrate and gravity separation tailings, and calculating the silver grade of the raw ore; S3, step-by-step gravity separation and automatic mineralogy analysis: performing at least two times of gravity separation on the sample with the same mass as that in step S2 to obtain at least three products with different density characteristics, i.e., first gravity separation concentrate, second gravity separation concentrate and combined gravity separation tailings, and preparing automatic mineralogy analysis samples of the products for analysis, measuring the types and silver content of silver minerals, the types and content of associated or wrapped minerals and their oxidation products in the silver ore sample, calculating the silver mineral metal distribution rate, and measuring the silver mineral intercrystalline ratio; S4, determination of chemical leaching correction coefficient: performing stepwise chemical leaching treatment on the sample obtained by mixing the second gravity separation concentrate and the combined gravity separation tailings in step S3 in a certain proportion, measuring the silver content in the leaching solution, and calculating the chemical leaching correction coefficient; S5, determination of gangue wrapping correction coefficient: performing quality and silver grade analysis on the final residue after chemical leaching in step S4, and calculating the gangue wrapping correction coefficient; S6, calculation of silver ore oxidation rate: based on the silver mineral metal distribution rate and the silver mineral intercrystalline ratio obtained in step S3, the chemical leaching correction coefficient calculated in step S4, and the gangue wrapping correction coefficient calculated in step S5, the silver ore oxidation rate is calculated.

2. The method for determining the oxidation rate of silver ore according to claim 1, characterized by, In step S6, the silver ore oxidation rate is marked as Q, and the calculation formula is: Q = Σ [ Ri.f×( Li.1×Dn'.f / (Dn'.f + Dn.f) + Li.2×O1 + Li.3×O2 ) ]; Wherein, Ri.f represents the silver mineral metal distribution rate, i is 1, 2, 3…, representing natural silver, sulfide silver and other types of silver respectively; f is 1, 2, 3, representing the intercrystalline state of silver mineral metal sulfide, the intercrystalline state of metal oxide, and the intercrystalline state of gangue mineral respectively; Dn.f and Dn'.f represent the content of associated or wrapped minerals and their oxidation products, wherein n is 1, 2, 3…, representing galena, sphalerite and chalcopyrite respectively; n' is 1, 2, 3…, representing the oxidation products of galena, sphalerite and chalcopyrite: lead oxide, zinc oxide and copper oxide respectively; Li.1, Li.2 and Li.3 represent the intercrystalline ratio of the corresponding silver mineral and metal sulfide, metal oxide and gangue mineral respectively; O1 represents the chemical leaching correction coefficient; O2 represents the gangue wrapping correction coefficient.

3. The method for determining the oxidation rate of silver ore according to claim 2, characterized by, In S3, the silver mineral metal distribution rate is marked as Ri.f, and the calculation formula is: Ri.f =te×Di.f×Di.f' / ∑(te×∑(Di.f×Di.f’)) Wherein, Di.f and Di.f' represent the silver mineral species and silver content, respectively, wherein i is the type of silver mineral, f is 1, 2, 3, representing the first gravity concentrate, the second gravity concentrate, and the combined gravity tailings, respectively, and f' is 1, 2, 3, representing the silver content of the target silver mineral in the first gravity concentrate, the second gravity concentrate, and the combined gravity tailings, respectively; te represents the yield of the gravity product; wherein t1 represents the yield of the first gravity concentrate; t2 represents the yield of the second gravity concentrate; t3 = 1 - t1 - t2 represents the yield of the combined gravity tailings.

4. The method for determining the oxidation rate of silver ore according to claim 3, characterized by, In step S4, the chemical leaching correction coefficient is marked as O1, and the calculation formula is: O1 = (P1×V) / [ (m×W×ΣRi.f)×Σ(Ri.f×(Li.1+ Li.2)) ]; Wherein, P1 represents the silver content in the leaching solution, V represents the volume of the leaching solution, m represents the mass of the mixed sample, and W represents the silver grade of the raw ore; Ri.f represents the metal distribution rate of the silver mineral; Li.1 and Li.2 represent the intercrystalline ratio of the i-th silver mineral and the metal sulfide and the metal oxide, respectively.

5. The method for determining the oxidation rate of silver ore according to claim 3, characterized by, In S5, the gangue package correction coefficient is marked as O2, and the calculation formula is: O2 = (P2×m1) / [ (m×W×ΣRi.f)×Σ(Ri.f×Li.3) ]; Wherein, P2 is the silver grade of the residue, m1 is the mass of the residue; m represents the mass of the mixed sample, and W represents the silver grade of the raw ore; Ri.f represents the metal distribution rate of the silver mineral; Li.3 represents the intercrystalline ratio of the silver mineral and the gangue mineral.

6. The method for determining the oxidation rate of silver ore according to claim 3, characterized by, In S3, the step-by-step gravity separation includes: First, the silver ore sample is subjected to a first gravity separation to separate a first gravity concentrate and a first gravity tailings; Second, the first gravity concentrate is subjected to a second gravity separation to separate a second gravity concentrate and a second gravity tailings; The first gravity tailings and the second gravity tailings are combined into a final combined gravity tailings; Thus, the yields of the first gravity concentrate, the second gravity concentrate, and the combined gravity tailings are t1, t2, and (1-t1-t2), respectively.

7. The method for determining the oxidation rate of silver ore according to claim 2, characterized by, In step S2, the silver grade of the raw ore is marked as W, and the calculation formula is: W = t×c1 + (1 - t)×c2; Wherein, t is the yield of the gravity concentrate, c1 is the silver grade of the gravity concentrate, and c2 is the silver grade of the gravity tailings.

8. The method for determining the oxidation rate of silver ore according to claim 2, characterized by, In step S4, the step-by-step chemical leaching includes the following steps: First, dilute hydrochloric acid is used to leach carbonates and part of the oxidized silver; Second, reverse aqua regia is used to leach sulfide-encapsulated silver and refractory silver minerals; Third, sodium sulfide and concentrated nitric acid are used to treat the residue to leach the silver that is severely encapsulated by minerals other than gangue.

9. The method for determining the oxidation rate of silver ore according to claim 1, characterized by, The silver mineral includes at least one of natural silver, argentite, stibian silver, and silver-containing tetrahedrite.

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