Method for detecting pyrite in talc raw ore

Abstract

The invention belongs to the technical field of detection. The invention provides a method for detecting pyrite in talc raw ore, which comprises the following steps: S1, collecting not less than 5kg of talc raw ore, crushing, uniformly mixing, and splitting to 1 + / -0.005 kg to obtain a sample to be detected; s2, preparing a heavy liquid with the density of 2.8-2.83 g / cm < 3 >, carrying out centrifugal treatment on the to-be-detected sample obtained in the step S1 by using the heavy liquid, and collecting a bottom precipitate; and S3, drying the bottom precipitate obtained in the step S2, and calculating the mass fraction of the bottom precipitate in the to-be-detected sample obtained in the step S1. The method can effectively improve the detection data accuracy of the pyrite in the talc raw ore.

Description

Technical Field

[0001] This invention belongs to the field of detection technology, specifically relating to a method for detecting pyrite in raw talc ore. Background Technology

[0002] Talc is a hydrothermal alteration mineral. Magnesium-rich minerals often transform into talc through hydrothermal alteration, hence talc often exhibits pseudomorphs such as olivine, enstatite, amphibole, and tremolite. Talc ore is often associated with other minerals, such as magnesite, dolomite, serpentine, chlorite, tremolite, siderite, quartz, and pyrite. These associated minerals can alter the chemical composition of the ore, making its color more vibrant and significantly affecting its physical properties. For example, the presence of magnesite increases the hardness of talc, while the presence of dolomite makes its texture finer. Pyrite, an associated mineral, has a hardness of 6-6.5, which can cause severe wear on grinding equipment during talc grinding and reduce the whiteness of the ground talc powder. Therefore, testing the pyrite content in raw talc ore can directly confirm whether the raw talc material is suitable for grinding, reducing unnecessary wear costs on grinding equipment and lowering the risk of substandard whiteness in the ground talc powder.

[0003] The existing detection method is versatile and simple to operate. First, take 1000g of sample passing through a 7mm sieve and pour it into a 35-mesh (420μm) circular test sieve with a diameter of 20cm. Rinse with running water (not lower than the laboratory grade III water standard). Observe the material remaining on the 35-mesh (420μm) sieve and check the number of pyrite particles. The definition of the quantity of pyrite in the raw ore is as follows: ① Pyrite quantity < 2 particles, defined as a small amount; ② Pyrite quantity 2-24 particles, defined as a large amount; Pyrite quantity > 24 particles, defined as a large amount. Specific detected pyrite particles are as follows: Figure 3 As shown in the image. This detection method is simple to operate and the results are intuitive.

[0004] However, focusing solely on the total number while ignoring the finer details can lead to early missed detections, resulting in a lower pyrite discovery rate than the actual data and inaccurate detection data. Summary of the Invention

[0005] To address the problems existing in the background art, the present invention provides a method for detecting pyrite in talc ore, which can effectively improve the accuracy of detection data.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for detecting pyrite in raw talc ore, comprising the following steps: S1. Collect no less than 5 kg of raw talc ore, crush it, mix it evenly, and reduce it to 1 ± 0.005 kg to obtain the sample to be tested. Talc ore is unevenly distributed in the stockpile (containing pyrite lumps, impurity bands, etc.), and small samples are prone to missing key areas; however, a large sample size of ≥5kg conforms to statistical principles (according to the central limit theorem, the larger the sample size, the smaller the sampling error). Stockpile sampling needs to cover spatial heterogeneity, and 5kg is a common threshold for balancing efficiency and accuracy. Through standardized sampling → controlled crushing → fine screening, a highly representative and low-error input sample was constructed, laying the foundation for subsequent separation.

[0007] S2, with a density of 2.8-2.83 g / cm³ 3 The heavy liquid was used to centrifuge the sample obtained from S1 and the bottom precipitate was collected. Talc has a density of 2.7-2.8 g / cm³. 3 Pyrite has a density of 4.9-5.2 g / cm³. 3 Choose a density slightly higher than the upper limit of talc (2.8-2.83 g / cm³). 3 This ensures that talc remains suspended on the upper layer of the heavy liquid (floats) while pyrite completely sinks to the bottom (sinks); by precisely matching the density difference of the minerals, non-destructive separation is achieved.

[0008] S3. After drying the bottom precipitate obtained in S2, calculate its mass fraction relative to the mass of the sample obtained in S1. The formula for calculating the mass fraction is: (Mass of dried precipitate / Mass of sample obtained in S1) × 100%.

[0009] By combining drying with simple calculations, reliable mass fractions can be obtained, avoiding heat damage or moisture interference. This is a key bridge connecting laboratory data with industrial applications.

[0010] This detection method is based on the density difference separation principle (heavy liquid centrifugation method). By precisely controlling the sampling, separation and drying processes, it achieves highly accurate and repeatable quantitative detection of pyrite in raw talc ore.

[0011] Furthermore, in S1, the nine-point plum blossom pattern sampling method is implemented according to GB / T 27405 to collect talc ore from different locations in the raw material stockpile.

[0012] Pyrite is often distributed in a scattered or nodular pattern, and the nine-point method can effectively capture its spatial variability. This method meets the minimum requirements for solid mineral sampling as per GB / T27405 (Laboratory Quality Control Standard), avoiding distorted results due to insufficient samples. The quincunx sampling pattern ensures forced coverage of the upper, middle, and lower layers of the stockpile, as well as the edge areas, avoiding biases caused by sampling only the surface or a single location, which could lead to the identification of "enriched" or "depleted" areas.

[0013] Furthermore, in S1, a jaw crusher is used for crushing.

[0014] Jaw crushers offer gentle crushing force, avoiding losses due to over-fine processing. Compared to hammer crushers, jaw crushers produce less dust, reducing the risk of fine pyrite particles escaping. They efficiently homogenize the minerals while preserving their integrity.

[0015] Furthermore, the particle size of the sample to be tested is ≤0.074mm.

[0016] A particle size ≤0.074mm ensures the liberation of pyrite monomers and prevents inclusions from remaining in talc, which could affect the separation effect. Fine particles settle more stably in heavy liquids, reducing misclassification caused by eddy current disturbances. This both improves the efficiency of heavy liquid separation and eliminates particle size interference.

[0017] Furthermore, the heavy liquid comprises bromoform and acetone.

[0018] Furthermore, the method for preparing the heavy liquid is as follows: using bromoform as the base liquid, while continuously stirring, acetone is added dropwise to the bromoform to adjust the density to the standard, thus obtaining the liquid.

[0019] The density of pure bromoform is approximately 2.89 g / cm³. 3 (Close to target value), providing a high-density framework as the base solution; acetone is a low-density solvent, with a density of ≈0.79 g / cm³. 3 After dropwise addition, the density of bromoform can be precisely adjusted to 2.8-2.83 g / cm³. 3 The mixture exhibits good stability and is not easily volatile (acetone inhibits bromoform decomposition), and its cost is lower than that of dedicated commercial heavy liquids.

[0020] Furthermore, in S2, the centrifugation conditions are: rotation speed 8000-8500 rpm, time 12-15 min.

[0021] Centrifugation conditions: 8000-8500 rpm, 12-15 min; high speed (8000+ rpm) utilizes centrifugal force to enhance sedimentation, compressing the process of natural sedimentation that takes several hours to minutes; time control (12-15 min) is sufficient to allow pyrite particles (≤0.074 mm) to settle completely, while avoiding the formation of talc particles that may sink due to prolonged centrifugation (false positive); ensuring accurate and reliable test data.

[0022] Furthermore, in S3, the drying temperature is 100±5℃, and the drying time is 3-5h.

[0023] The drying temperature is 100±5℃, which can completely remove moisture (water boils at 100℃) without triggering a chemical reaction. The drying time is 3-5 hours. 3 hours is sufficient to dry the internal moisture of particles ≤0.074mm (capillary action is slow); the upper limit of 5 hours should be avoided to prevent over-drying. Excessive drying time does not improve accuracy but increases energy consumption and oxidation risk.

[0024] This application has the following beneficial effects: This detection method first constructs a highly representative and low-error input sample through standardized sampling, controlled crushing, and fine sieving, laying the foundation for subsequent separation.

[0025] Then select a density slightly higher than the upper limit of talc, 2.8-2.83 g / cm³. 3 By controlling the high speed of centrifugation and the time, the complete settling time is compressed, avoiding the talc particles from being carried down and sinking due to prolonged centrifugation (false positive). This ensures that while the talc is suspended in the upper layer of the heavy liquid (floating), the pyrite completely sinks to the bottom (sinking), achieving non-destructive separation.

[0026] Finally, by using low-temperature drying and simple calculations, a reliable mass fraction is obtained, avoiding heat damage or moisture interference, and ensuring high accuracy and repeatability of the pyrite detection data in the raw talc ore. Attached Figure Description

[0027] Figure 1 This is a trend chart comparing the detection data of Example 1 and Comparative Examples 1-3 in the experimental examples of the present invention. Figure 2 This is a trend chart comparing the error range / uncertainty of three detection data from Example 1 and Comparative Examples 1-3 in the experimental examples of this invention; Figure 3 The image shows a physical sample of pyrite detected in the background / existing technology of this invention. Detailed Implementation

[0028] The present application will be further described in detail below with reference to the embodiments.

[0029] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are all commercially available.

[0030] Example 1: A method for detecting pyrite in raw talc ore, comprising the following steps: S1. Following the requirements of GB / T 27405, a nine-point plum blossom pattern sampling method was used to collect talc ore from different locations in the raw material stockpile. Specifically, 5 kg of talc ore was collected, crushed using a jaw crusher, mixed evenly, and reduced to 1 kg to obtain the sample to be tested. The particle size of the sample to be tested is ≤0.074 mm.

[0031] By standardizing sampling, controlling crushing, and fine screening, a highly representative and low-error input sample was constructed, laying the foundation for subsequent separation.

[0032] S2, prepared using bromoform and acetone, yields a density of 2.82 g / cm³. 3The heavy liquid is prepared as follows: using bromoform as the base liquid, while continuously stirring, acetone is added dropwise to the bromoform until the density reaches the target. Then, the heavy liquid is used to centrifuge the sample obtained in S1. The centrifugation conditions are: 8000-8500 rpm, 12-15 min, and the bottom precipitate is collected.

[0033] Choose a density slightly higher than the upper limit of talc, 2.81 g / cm³. 3 By controlling the high speed of centrifugation and the time, the complete settling time is compressed, avoiding the talc particles from being carried down and sinking due to prolonged centrifugation (false positive). This ensures that while the talc is suspended in the upper layer of the heavy liquid (floating), the pyrite completely sinks to the bottom (sinking), achieving non-destructive separation.

[0034] S3. The bottom precipitate obtained in S2 is dried at 100℃ for 4.5 hours. Then, the mass fraction of the dried precipitate relative to the sample obtained in S1 is calculated. The formula for calculating the mass fraction is: (Mass of dried precipitate / Mass of sample obtained in S1) × 100%.

[0035] By using low-temperature drying and simple calculations, a reliable mass fraction can be obtained, avoiding heat damage or moisture interference, and ensuring high accuracy and repeatability of the detection data of pyrite in raw talc ore.

[0036] Comparative Example 1: The difference between this comparative example and Example 1 is that the particle size of the sample to be tested is ≤0.2mm.

[0037] Comparative Example 2: The difference between this comparative example and Example 1 is that the heavy liquid is replaced with bromoform.

[0038] Comparative Example 3: The difference between this comparative example and Example 1 is that the particle size of the sample to be tested is ≤0.2mm; and the heavy liquid is replaced with bromoform.

[0039] Experimental example: For Example 1 and Comparative Examples 1-3, each was tested three times, and the results are shown in Table 1.

[0040] Table 1. Test Data for Experimental Examples Results Analysis: Combining the data in Table 1 and... Figures 1-2 Analysis of Example 1 and Comparative Examples 1-3 shows that the detection data of pyrite in the raw talc ore of the present invention (Example 1) has high accuracy and high repeatability.

[0041] Specifically, by comparing Example 1 and Comparative Example 1, it can be seen that, compared with the particle size of the sample to be tested in Comparative Example 1 being ≤0.2mm, the particle size of the sample to be tested in Example 1 being ≤0.074mm, which is beneficial to improving the repeatability of the detection data of pyrite in talc ore and reducing the data error between multiple tests.

[0042] Specifically, comparing Example 1 and Comparative Example 2, it can be seen that, compared to Comparative Example 2 which used bromoform as the centrifugal liquid, Example 1, which used bromoform and acetone, prepared a solution with a density of 2.82 g / cm³. 3 Using heavy liquid as a centrifuge fluid can also help improve the repeatability of pyrite detection data in raw talc ore and reduce data errors between multiple tests.

[0043] Comparing with Comparative Example 3, it can be seen that the particle size of the sample to be tested is ≤0.074mm, and the density prepared using bromoform and acetone is 2.82g / cm³. 3 Using heavy liquid as a centrifugal fluid can synergistically improve the repeatability of pyrite detection data in talc ore, synergistically reduce data errors between multiple tests, and ensure small error and high accuracy in a single test.

[0044] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0045] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for detecting pyrite in raw talc ore, characterized in that, Includes the following steps: S1. Collect no less than 5 kg of raw talc ore, crush it, mix it evenly, and reduce it to 1 ± 0.005 kg to obtain the sample to be tested. S2, with a density of 2.8-2.83 g / cm³ 3 The heavy liquid was used to centrifuge the sample obtained from S1 and the bottom precipitate was collected. S3. After drying the bottom precipitate obtained in S2, calculate its mass fraction relative to the sample obtained in S1.

2. The method for detecting pyrite in talc ore according to claim 1, characterized in that, In S1, the nine-point plum blossom pattern sampling method is implemented according to GB / T27405 to collect talc ore from different locations in the raw material stockpile.

3. The method for detecting pyrite in talc ore according to claim 1, characterized in that, In S1, a jaw crusher is used for crushing.

4. The method for detecting pyrite in talc ore according to claim 1, characterized in that, The particle size of the sample to be tested is ≤0.074 mm.

5. The method for detecting pyrite in talc ore according to claim 1, characterized in that, The heavy liquid includes bromoform and acetone.

6. The method for detecting pyrite in talc ore according to claim 1 or 5, characterized in that, The method for preparing the heavy liquid is as follows: using bromoform as the base liquid, while continuously stirring, acetone is added dropwise to the bromoform to adjust the density to the standard.

7. The method for detecting pyrite in talc ore according to claim 1, characterized in that, In S2, the centrifugation conditions are: rotation speed 8000-8500 rpm, time 12-15 min.

8. The method for detecting pyrite in talc ore according to claim 1, characterized in that, In S3, the drying temperature is 100±5℃ and the drying time is 3-5h.

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