Method for accurately determining source of heavy metals in coal mine water

Abstract

The application discloses a method for accurately determining the source of heavy metals in coal mine water, and relates to the field of mine water treatment. The method can accurately and quantitatively characterize the heavy metals in the mine water, and further realizes the purpose of obtaining the source of the heavy metals in the mine water. The method comprises the following steps: step 1, obtaining water chemical index parameters; step 2, determining and defining the types of heavy metals exceeding the standard; step 3, preliminarily determining the potential source of the heavy metals in the mine water; step 4, again determining the potential source of the heavy metals in the mine water; step 5, determining the possible source of the heavy metals in the mine water; step 6, performing coincidence analysis on the determination results of steps 3-5, and the coincidence object is the key source of the heavy metals in the mine water; step 7, taking a coal sample to perform a heavy metal leaching experiment, and obtaining typical heavy metal leaching parameters; and step 8, finally determining the true source of the heavy metals in the mine water. Finally, the source of the heavy metals in the mine water can be accurately identified, so as to facilitate the resource treatment of the mine water.

Description

Technical Field

[0001] This invention relates to the field of mine water treatment, and more specifically to a method for accurately determining the source of heavy metals in coal mine water. Background Technology

[0002] With the high-intensity mining of coal in my country, the discharge of mine water has also increased dramatically. Mine water contains many toxic and harmful heavy metals, making it unusable directly. However, direct discharge of mine water not only severely wastes water resources in coal-producing areas but also pollutes surrounding water bodies and damages the ecological environment of mining areas. Therefore, accurately determining the source of heavy metals in mine water is of great significance for the resource-based treatment of mine water, alleviating the contradiction between mine water waste and water environmental protection and utilization, avoiding damage to the ecological environment of mining areas, and achieving green mining of coal resources.

[0003] Heavy metals in mine water primarily originate from the surrounding coal and rock mass. On one hand, the long-term interaction between the coal and rock mass and groundwater causes heavy metals accumulated in the coal and rock mass to dissolve into the mine water. On the other hand, coal mining activities alter the original environment of the coal and rock mass, also leading to heavy metals entering the mine water. Currently, research on heavy metal removal technologies in coal mines mainly focuses on the processes, technologies, and equipment for removing heavy metals from mine water, with relatively little research on the sources of heavy metals in mine water. Conventional methods such as elemental concentration analysis and correlation analysis can only provide qualitative or semi-quantitative conclusions when identifying the sources of heavy metals in mine water, and cannot achieve precise and quantitative characterization.

[0004] Therefore, how to accurately and quantitatively characterize heavy metals in mine water has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] To address the above problems, this invention proposes a method for accurately determining the source of heavy metals in coal mine water. This method can accurately and quantitatively characterize heavy metals in mine water, thereby achieving the goal of obtaining the source of heavy metals in mine water.

[0006] The technical solution of the present invention includes the following steps:

[0007] Step 1: Collect and test rainwater, surface water, groundwater, groundwater from various aquifers, and mine water in the coal mine to obtain their water chemical parameters;

[0008] Step 2: Determine the types of heavy metals exceeding the standard based on the hydrochemical parameters of the mine water and define them as typical heavy metals of the mine.

[0009] Step 3: Compare the hydrochemical types, δD, and δ of mine water with rainwater, surface water, unconfined groundwater, and groundwater from various aquifers. 18 O value, to preliminarily determine the potential sources of heavy metals in mine water;

[0010] Step 4: Based on the typical heavy metal concentrations of rainwater, surface water, groundwater, and groundwater in each aquifer, determine the potential sources of heavy metals in the mine water again.

[0011] Step 5: Using the systematic clustering method, rainwater, surface water, groundwater, groundwater from various aquifers, and mine water are classified according to water chemical index parameters to determine the possible sources of heavy metals in the mine water.

[0012] Step 6: Perform overlap analysis on the judgment results of Steps 3-5, and identify the key sources of heavy metals in mine water that overlap.

[0013] Step 7: Take coal samples for heavy metal leaching experiments to obtain typical heavy metal leaching parameters;

[0014] Step 8: Based on the typical heavy metal leaching parameters of the coal sample and the typical heavy metal parameters of the key sources, the chemical mass balance method is used to calculate the contribution rate of each to the heavy metals in the mine water, and finally determine the true source of the heavy metals in the mine water.

[0015] In the above:

[0016] Step 3 determines that the conditions for identifying a potential source of heavy metals in mine water are that the following three conditions are met simultaneously:

[0017] Condition 1: Same water chemistry type as mine water;

[0018] Condition 2, δD = (90%~110%) δD 矿井水 ;

[0019] Condition 3, δ 18 O = (90%~110%)δ 18 O 矿井水 ;

[0020] In the above, δD is the value of deuterium, a stable isotope of hydrogen. 矿井水 The value of deuterium, a stable isotope of hydrogen in mine water, is given by δ. 18 O is a stable isotope of oxygen. 18 The value of O, δ 18 O 矿井水 Stable isotopes of oxygen in mine water 18 The value of O.

[0021] Step 4 determines that a potential source of heavy metals in mine water meets any one of the following conditions:

[0022] Condition 1: The concentration of any typical heavy metal exceeds the standard;

[0023] Condition 2: The concentration of any typical heavy metal reaches 10% of the concentration of that typical heavy metal in the mine water.

[0024] Step 5 determines the possible source of heavy metals in mine water as follows: it is classified in the most recent category as mine water;

[0025] The equations involved in the systematic clustering method are:

[0026] Based on conventional ions, typical heavy metals, and δD and δ¹⁸O in rainwater, surface water, groundwater from various aquifers, and mine water. 18 O-parameters construct the matrix:

[0027] ;

[0028] Where, x mn Let n be the water chemical index parameter of the m-th water sample, where m = 4 + total number of aquifers and n = 9 + total number of typical heavy metals.

[0029] Equation for eliminating dimensional differences:

[0030] , where x ij These are the corresponding values ​​of the water chemical parameters in the original water sample after eliminating dimensional differences.

[0031] Similarity representation equation:

[0032] d represents the similarity distance between the two types of water samples, i represents the i-th water sample, j represents the j-th chemical index parameter, and k represents the k-th water sample.

[0033] Step 7 determines the true source of heavy metals in mine water based on the following conditions:

[0034] Condition 1: Contribution rate greater than 5%;

[0035] The equations involved in the chemical mass balance method are:

[0036] Equation for calculating contribution concentration:

[0037] ;

[0038] Where J = 1 + total number of key sources; C i The typical heavy metal concentration i in mine water; F ij The mass proportion of typical heavy metal i in a coal sample or key source j to all typical heavy metals; S j The contribution concentration of coal sample or key source j;

[0039] Contribution rate calculation equation:

[0040] .

[0041] When performing step 8, if the total number of typical heavy metals is greater than or equal to the total number of key sources plus 1, the chemical mass balance method has a solution. Complete all steps 1 to 8 to determine the source of heavy metals in the mine water.

[0042] When the total number of typical heavy metals is less than the total number of key sources plus 1, the chemical mass balance method has no solution. Only steps 1 to 6 need to be completed to determine that the key source is the heavy metal source in the mine water.

[0043] The beneficial effects of this invention are as follows:

[0044] This invention provides a method for accurately determining the source of heavy metals in coal mine water. It is applicable to the rapid and accurate identification of heavy metal sources in coal mine water. By comprehensively analyzing the differences between the water chemical parameters of various water sources in the mining area and those of the mine water, the method can quickly and accurately identify the source of heavy metals in the mine water. This helps reduce heavy metal pollution in mine water and promote the resource-based treatment of mine water, thereby alleviating the contradiction between mine water waste and water environmental protection and water resource utilization, avoiding damage to the ecological environment of the mining area, and achieving the goal of green mining of coal resources. Attached Figure Description

[0045] Figure 1 This is the genealogy diagram of the system clustering method in this case. Detailed Implementation

[0046] To clearly illustrate the technical features of this patent, the following detailed description is provided through specific embodiments and in conjunction with the accompanying drawings.

[0047] The purpose of this case is to identify which of the following sources of heavy metals in mine water are rainwater, surface water, groundwater, and groundwater from various aquifers: This includes the following steps:

[0048] Step 1: Collect and test rainwater, surface water, groundwater, groundwater from various aquifers, and mine water in the coal mine to obtain their water chemical parameters;

[0049] Specifically, rainwater from coal mines, surface water, Quaternary unconfined water, groundwater from the Middle Jurassic Zhiluo Formation aquifer (hereinafter referred to as Aquifer I), groundwater from inter-coal sandstone aquifer (hereinafter referred to as Aquifer II), and mine water were collected and tested to obtain their hydrochemical parameters, as shown in Table 1.

[0050] Table 1. Water Chemical Parameters

[0051] rainwater Surface water diving I. Water content II. Water content Mine water <![CDATA[K + ]]> 8.64 19.16 17.59 20.31 28.93 31.67 <![CDATA[Ca 2+ ]]> 16.47 64.84 216.17 127.56 197.45 203.32 <![CDATA[Na + ]]> 7.16 498.15 945.97 1756.18 3690.75 4860.17 <![CDATA[Mg 2+ ]]> 4.52 37.24 145.76 97.86 160.73 207.41 <![CDATA[SO4 2- ]]> 17.55 375.62 617.97 1256.81 3142.22 4057.16 <![CDATA[HCO3 - ]]> 37.89 235.18 364.14 504.43 424.14 396.17 <![CDATA[Cl - ]]> 9.31 443.29 794.24 1597.71 3071.57 3475.77 Fe ND ND ND ND 0.03 0.05 Mn ND ND ND ND ND ND Cu ND ND ND ND ND ND Zn ND ND ND 0.06 0.12 0.16 Hg ND ND ND 0.00005 0.00011 0.00014 As ND ND ND ND ND ND Se ND ND 0.00003 0.00004 0.00023 0.0003 Cd ND ND ND ND 0.009 0.05 Cr ND ND ND ND ND ND Pb ND ND ND 0.0097 0.19 0.27 δD / % -100.43 -117.35 -101.45 -123.48 -124.51 -121.51 <![CDATA[δ 18 O / %]]> -12.45 -13.11 -16.12 -16.54 -14.69 -15.72 Water chemistry types <![CDATA[Ca 2+ -HCO3 - ]]> <![CDATA[Na + -Cl - ]]> <![CDATA[Na + -SO4 2- -Cl - ]]> <![CDATA[Na + -SO4 2- -Cl - ]]> <![CDATA[Na + -SO4 2- -Cl - ]]> <![CDATA[Na + -SO4 2- -Cl - ]]>

[0052] Unit: mg / L, ND: If the detection result is below the method detection limit, it is calculated as 0.

[0053] The water chemical parameters include seven common ions, K. + Ca2+ Na + Mg 2+ SO4 2- HCO3 - Cl - Ten common heavy metals in mine water are Fe, Mn, Cu, Zn, Hg, As, Se, Cd, Cr, Pb, as well as δD and δ 18 O.

[0054] Step 2: Determine the types of heavy metals exceeding the standard based on the hydrochemical parameters of the mine water and define them as typical heavy metals of the mine. Specifically, the Class III standard of the Groundwater Quality Standard (GB / T 14848-2017) is used as the condition for determining typical heavy metals. In this case, Cd and Pb are determined to be typical heavy metals exceeding the standard based on the hydrochemical parameters of the mine water.

[0055] Step 3: Compare the hydrochemical types, δD, and δ of mine water with rainwater, surface water, unconfined groundwater, and groundwater from various aquifers. 18 O value, to preliminarily determine the potential sources of heavy metals in mine water;

[0056] The following three conditions must be met simultaneously for a mine water to be identified as a potential source of heavy metals:

[0057] Condition 1: Same water chemistry type as mine water;

[0058] Condition 2, δD = (90%~110%) δD 矿井水 ;

[0059] Condition 3, δ 18 O = (90%~110%)δ 18 O 矿井水 ;

[0060] In the above, δD is the value of deuterium, a stable isotope of hydrogen. 矿井水 The value of deuterium, a stable isotope of hydrogen in mine water, is given by δ. 18 O is a stable isotope of oxygen. 18 The value of O, δ 18 O 矿井水 Stable isotopes of oxygen in mine water 18 The value of O.

[0061] This embodiment compares the hydrochemical types, δD, and δ of mine water with rainwater, surface water, unconfined groundwater, groundwater from aquifer I, and groundwater from aquifer II. 18 Based on the O value, it was initially determined that aquifer I and aquifer II are potential sources of heavy metals in the mine water.

[0062] Step 4: Based on the typical heavy metal concentrations of rainwater, surface water, groundwater, and groundwater in each aquifer, determine the potential sources of heavy metals in the mine water again.

[0063] The following conditions must be met for a mine water to be identified as a potential source of heavy metals:

[0064] Condition 1: The concentration of any typical heavy metal exceeds the standard;

[0065] Condition 2: The concentration of any typical heavy metal reaches 10% of the concentration of that typical heavy metal in the mine water.

[0066] In this embodiment, based on the typical heavy metal concentrations of rainwater, surface water, groundwater, groundwater in aquifer I, and groundwater in aquifer II, it is determined that aquifer II is a potential source of heavy metals in mine water.

[0067] Step 5: Using the systematic clustering method, rainwater, surface water, groundwater, groundwater from various aquifers, and mine water are classified according to water chemical index parameters to determine the possible sources of heavy metals in the mine water.

[0068] The criteria for determining whether heavy metals in mine water are a possible source are: the water must be classified in the most recent category as mine water.

[0069] The equations involved in the systematic clustering method are:

[0070] Based on conventional ions, typical heavy metals, and δD and δ¹⁸O in rainwater, surface water, groundwater from various aquifers, and mine water. 18 O-parameters construct the matrix:

[0071] ;

[0072] Where, x mn This refers to the nth hydrochemical parameter in the mth water sample, where m = 4 + total number of aquifers and n = 9 + total number of typical heavy metals. In m = 4 + total number of aquifers, the "4" represents the four basic water bodies: rainwater, surface water, groundwater, and mine water. In n = 9 + total number of typical heavy metals, the "9" represents seven common ions (K⁺, Ca²⁺, Na⁺, Mg²⁺, SO₄²⁻, HCO₃⁻, Cl⁻) and δD, δ¹⁻. 8 O isotope parameters.

[0073] Equation for eliminating dimensional differences:

[0074] , where x ij These are the corresponding values ​​of the water chemical parameters in the original water sample after eliminating dimensional differences.

[0075] Similarity representation equation:

[0076] d represents the similarity distance between the two types of water samples, i represents the i-th water sample, j represents the j-th chemical index parameter, and k represents the k-th water sample.

[0077] In this embodiment, rainwater, surface water, groundwater, groundwater from aquifer I, groundwater from aquifer II, and mine water are classified as follows: Figure 1 As shown in Table 2, the II aquifer is identified as a possible source of heavy metals in the mine water.

[0078] Table 2 Distance Characterization Table for System Clustering

[0079] rainwater Surface water diving Ⅰ Including II includes Mine water rainwater 0 0.87 1.75 2.12 2.87 3.67 Surface water 0.87 0 1.31 1.42 2.34 3.23 diving 1.75 1.31 0 1.30 2.12 2.93 Ⅰ Including 2.12 1.42 1.30 0 1.68 2.57 II includes 2.87 2.34 2.12 1.68 0 1.16 Mine water 3.67 3.23 2.93 2.57 1.16 0

[0080] Step 6: Perform overlap analysis on the judgment results of Steps 3-5, and identify the key sources of heavy metals in mine water that overlap.

[0081] In this embodiment, the overlapping object II aquifer is determined to be a key source of heavy metals in mine water.

[0082] Step 7: Take coal samples for heavy metal leaching experiments and obtain typical heavy metal leaching parameters, as shown in Table 3.

[0083] Table 3 Typical Heavy Metal Leaching Parameters for Coal Samples

[0084] Cd Pb coal sample 0.039 0.011

[0085] Unit: mg / L

[0086] Step 8: Based on the typical heavy metal leaching parameters of the coal sample and the typical heavy metal parameters of the key sources, the chemical mass balance method is used to calculate the contribution rate of each to the heavy metals in the mine water, and finally determine the true source of the heavy metals in the mine water.

[0087] The conditions for determining the true source of heavy metals in mine water are:

[0088] Condition 1: Contribution rate greater than 5%;

[0089] The equations involved in the chemical mass balance method are:

[0090] Equation for calculating contribution concentration:

[0091] ;

[0092] Where J = 1 + total number of key sources; C i The typical heavy metal concentration i in mine water; F ij The mass proportion of typical heavy metal i in a coal sample or key source j to all typical heavy metals; S j The contribution concentration of coal sample or key source j;

[0093] Contribution rate calculation equation:

[0094] .

[0095] In the above:

[0096] When the total number of typical heavy metals is greater than or equal to the total number of key sources plus 1; the chemical mass balance method has a solution, complete all steps 1 to 8 to determine the source of heavy metals in mine water;

[0097] When the total number of typical heavy metals is less than the total number of key sources plus 1, the chemical mass balance method has no solution. Only steps 1 to 6 need to be completed to determine that the key source is the heavy metal source in the mine water.

[0098] As shown in Table 4, this implementation example ultimately determined that the II aquifer and coal seam were the true sources of heavy metals in the mine water.

[0099] Table 4 Contribution Rate of Heavy Metals

[0100] II Aquifer coal seam Contribution rate / % 84.89 15.11

[0101] There are many specific ways to implement this invention. The above description is only a preferred embodiment of this invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of this invention, and these improvements should also be considered within the scope of protection of this invention.

Claims

1. A method for accurately determining the source of heavy metals in coal mine water, characterized in that, Includes the following steps: Step 1: Collect and test rainwater, surface water, groundwater, groundwater from various aquifers, and mine water in the coal mine to obtain their water chemical parameters; Step 2: Determine the types of heavy metals exceeding the standard based on the hydrochemical parameters of the mine water and define them as typical heavy metals of the mine. Step 3: Compare the hydrochemical types, δD, and δ of mine water with rainwater, surface water, unconfined groundwater, and groundwater from various aquifers. 18 O value, to preliminarily determine the potential sources of heavy metals in mine water; Step 3 determines that the conditions for identifying a potential source of heavy metals in mine water are that the following three conditions are met simultaneously: Condition 1: Same water chemistry type as mine water; Condition 2, δD = (90%~110%) δD 矿井水 ; Condition 3, δ 18 O = (90% - 110%)δ 18 O 矿井水 ; In the above, δD is the value of deuterium, a stable isotope of hydrogen. 矿井水 The value of deuterium, a stable isotope of hydrogen in mine water, is given by δ. 18 O is a stable isotope of oxygen. 18 The value of O, δ 18 O 矿井水 Stable isotopes of oxygen in mine water 18 The value of O; Step 4: Based on the typical heavy metal concentrations of rainwater, surface water, groundwater, and groundwater in each aquifer, determine the potential sources of heavy metals in the mine water again. Step 4 determines that a potential source of heavy metals in mine water meets any one of the following conditions: Condition 1: The concentration of any typical heavy metal exceeds the standard; Condition 2: The concentration of any typical heavy metal reaches 10% of the concentration of that typical heavy metal in the mine water; Step 5: Using the systematic clustering method, rainwater, surface water, groundwater, groundwater from various aquifers, and mine water are classified according to water chemical index parameters to determine the possible sources of heavy metals in the mine water. Step 6: Perform overlap analysis on the judgment results of Steps 3-5, and identify the key sources of heavy metals in mine water that overlap. Step 7: Take coal samples for heavy metal leaching experiments to obtain typical heavy metal leaching parameters; If the total number of typical heavy metals is greater than or equal to the total number of key sources plus 1, proceed to the next step; if the total number of typical heavy metals is less than the total number of key sources plus 1, then the result of step 6 is determined as the true source of heavy metals in the mine water. Step 8: Based on the typical heavy metal leaching parameters of coal samples and the typical heavy metal parameters of key sources, the chemical mass balance method is used to calculate the contribution rate of each to the heavy metals in the mine water, and finally determine the true source of heavy metals in the mine water. The criterion for determining the true source of heavy metals in mine water is that the contribution rate is greater than 5%. The equations involved in the chemical mass balance method are: Equation for calculating contribution concentration: ； Where J = 1 + total number of key sources; C i The typical heavy metal concentration i in mine water; F ij The mass proportion of typical heavy metal i in a coal sample or key source j to all typical heavy metals; S j The contribution concentration of coal sample or key source j; Contribution rate calculation equation: 。 2. The method for accurately determining the source of heavy metals in coal mine water according to claim 1, characterized in that, Step 5 determines the possible source of heavy metals in mine water as follows: it is classified in the most recent category as mine water; The equations involved in the systematic clustering method are: Based on conventional ions, typical heavy metals, and δD and δ¹⁸O in rainwater, surface water, groundwater from various aquifers, and mine water. 18 O-parameters construct the matrix: ； Where, x mn Let n be the water chemical index parameter of the m-th water sample, where m = 4 + total number of aquifers and n = 9 + total number of typical heavy metals. Equation for eliminating dimensional differences: , where x ij These are the corresponding values ​​of the water chemical parameters in the original water sample after eliminating dimensional differences. Similarity representation equation: d represents the similarity distance between the two types of water samples, i represents the i-th water sample, j represents the j-th chemical index parameter, and k represents the k-th water sample.

3. The method for accurately determining the source of heavy metals in coal mine water according to claim 1, characterized in that, When performing step 8, if the total number of typical heavy metals is greater than or equal to the total number of key sources plus 1, the chemical mass balance method has a solution. Complete all steps 1 to 8 to determine the source of heavy metals in the mine water. When the total number of typical heavy metals is less than the total number of key sources plus 1, the chemical mass balance method has no solution. Only steps 1 to 6 need to be completed to determine that the key source is the heavy metal source in the mine water.

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