Rapid quantitative evaluation method for comprehensive performance of semi-hydrated phosphogypsum filling material

Abstract

The invention discloses a rapid quantitative evaluation method for comprehensive performance of a semi-hydrated ardealite filling material, and belongs to the technical field of performance evaluation of semi-hydrated ardealite-based paste filling materials. The method comprises the following steps: taking original HPG as a cementing material, quicklime as a modifier and phosphorus total tailings as an inert material in a laboratory, then adding water, mixing to prepare HPG-based paste filling slurry, rapidly determining the pH value of the slurry, analyzing the acid-base neutralization reaction degree, simultaneously carrying out a filling material performance determination test, and constructing a filling material performance calculation model taking the pH value as an independent variable. And finally, directly receiving the filling slurry from a filling material preparation site, measuring the pH value of the slurry, and substituting the pH value into the calculation model to obtain the performance index of the HPG-based paste filling material, so that the rapid, accurate and quantitative evaluation of the material performance is realized, and the adjustment of the quicklime mixing amount of the filling material in the production process is timely guided to ensure that the filling requirement is met.

Description

Technical Field

[0001] The invention relates to a method for quickly and quantitatively evaluating the comprehensive performance of a hemihydrate phosphogypsum filling material, and belongs to the technical field of performance evaluation of hemihydrate phosphogypsum-based paste filling materials. Background Art

[0002] Hemihydrated phosphogypsum (HPG)-based paste filling materials provide an important path for synergistically solving the problems of large-scale disposal of phosphogypsum and low-cost filling materials in mines. They have been widely used in disaster management of underground mine goafs. This material is prepared by mixing original HPG as a cementing material, alkaline materials such as quicklime as a modifier, and phosphorus tailings or dihydrated phosphogypsum as an inert material. Quicklime reacts with P2O5 and F in HPG to form a paste filling material. - The neutralization reaction of acidic impurities such as alkali and alkali determines the water exudation, coagulation, strength, and environmental performance of the filling material. Exploring the degree of acid-base neutralization reactivity is a prerequisite for evaluating whether the performance of HPG-based filling materials meets the safety and environmental protection requirements of mines. However, due to the influence of the upstream wet-process phosphoric acid production process, the acidic impurity content of HPG produced at different times fluctuates greatly, and the degree of acid-base neutralization reactivity changes dynamically and has high uncertainty, making it difficult to quickly and immediately evaluate the performance of HPG-based paste filling materials during the production process. Furthermore, the mapping relationship between the internal neutralization reactivity of HPG-based paste filling materials and their performance is unclear, making it impossible to provide accurate quantitative guidance for adjusting the quicklime content of the filling material from a production perspective. Therefore, it is necessary to construct a rapid quantitative evaluation method for the comprehensive performance of HPG-based paste filling materials based on rapid pH testing of the filling slurry and mathematical quantitative calculation of filling performance indicators to ensure production safety and environmental friendliness during the filling mining process. Summary of the Invention

[0003] To address or partially address the problems existing in related technologies, the present invention provides a method for rapid quantitative evaluation of the comprehensive properties of hemihydrate phosphogypsum filling materials. The comprehensive properties include bleeding, setting, strength, and environmental performance, specifically bleeding rate, initial setting time, final setting time, uniaxial compressive strength, and leachate total phosphorus and fluoride content.

[0004] The present invention provides a method for rapid quantitative evaluation of the comprehensive performance of hemihydrate phosphogypsum filling materials, comprising the following steps: (1) Using the same batch of hemihydrate phosphogypsum, hemihydrate phosphogypsum-based paste filling material slurry was prepared in the laboratory. The slurry mass concentration and the total tailings content were fixed. The quicklime content was adjusted within the range of 0% to 3% based on the mass of hemihydrate phosphogypsum. (2) Then, a portion of the hemihydrated phosphogypsum-based paste filling material slurry was taken and allowed to stand for 10 minutes, and then vacuum filtered to measure the pH value of the filtrate under the corresponding quicklime dosage conditions; at the same time, the remaining hemihydrated phosphogypsum-based paste filling material slurry was taken to carry out a filling material comprehensive performance test to measure the filling material bleeding rate, setting time, strength, and total phosphorus content and fluoride content of the leachate; (3) Using regression analysis method to construct a mathematical calculation model of the performance indicators of hemihydrate phosphogypsum-based paste filling materials with respect to pH value; (4) Directly collect the semi-hydrated phosphogypsum-based paste filling slurry from the filling material preparation site, quickly measure the pH value of the slurry after standing for 10 minutes, and substitute it into the calculation model obtained in step (3) to obtain the performance index parameters of the semi-hydrated phosphogypsum-based paste filling material.

[0005] The present invention also carries out a comprehensive performance measurement experiment of the filling slurry to verify the calculation accuracy of each performance index parameter; when the error is within 15%, it indicates that the calculation model has high accuracy; otherwise, the model is continuously optimized until the model calculation accuracy meets the requirements.

[0006] This invention, based on a rapid quantitative evaluation method for the comprehensive performance of hemihydrate phosphogypsum filling materials, can adjust the proportion of hemihydrate phosphogypsum-based paste filling materials to meet mine filling requirements. Specifically, the method determines whether the performance parameters of the hemihydrate phosphogypsum-based paste filling material meet the filling requirements. If the filling requirements are met, normal filling is carried out. If not, the quicklime content is adjusted until the filling material performance meets the requirements.

[0007] Preferably, the mass proportion of soluble P2O5 in the hemihydrate phosphogypsum is 0.3% to 0.8%, and the mass proportion of soluble F - The mass ratio is 0.2%~0.35%.

[0008] Preferably, the effective calcium oxide content of the quicklime is not less than 80%.

[0009] Preferably, in step (2), the preparation method of the HPG-based paste filling material slurry comprises: adding hemihydrated phosphogypsum, quicklime, whole tailings and water into an iron container at the same time, and then stirring for 3 minutes.

[0010] Preferably, in step (2), the mass concentration of the HPG-based paste filling material slurry is 59% to 71%; and the total tailings content is 0 to 100% based on the mass of hemihydrate phosphogypsum.

[0011] Preferably, the vacuum filtration is performed by using a vacuum water circulation pump to filter the filling slurry, the filter medium is a 0.45 micron filter membrane, and the filtration time is 1 minute.

[0012] Preferably, the pH value is measured using a pH detector, and the pH value is measured three times at different positions in the filtrate within 1 minute and the average value is taken.

[0013] The water bleeding rate test includes: pouring the semi-hydrated phosphogypsum-based paste filling slurry into a 500 ml beaker and letting it stand, measuring the amount of exuded water every 5 minutes, and measuring it every 1 minute when the amount of exuded water is significantly reduced, and calculating the water bleeding rate based on the total amount of exuded water.

[0014] The setting time test is carried out in accordance with the national standard GB / T 1346-2011, and the setting time includes the initial setting time and the final setting time.

[0015] The strength test is carried out in accordance with the industry standard JGJ / T 70-2009, and refers to the uniaxial compressive strength of the HPG-based filling specimens after curing for 3 days under standard curing conditions.

[0016] The phosphorus and fluoride leaching test was conducted in accordance with the industry standard HJ 557-2010, with total phosphorus determined by ammonium molybdate spectrophotometry and fluoride determined by ion selective electrode method.

[0017] The technical solution provided by the present invention can have the following beneficial effects: This method comprehensively evaluates the performance indicators of the filling material throughout its setting and curing process, including water bleeding rate, setting time, uniaxial compressive strength, and phosphorus and fluoride extract concentration, rather than being limited to single surface performance indicators. Furthermore, by precisely measuring the pH value of the filling slurry, this method enables simple, rapid, and quantitative evaluation of the comprehensive performance of HPG-based paste filling materials, reducing the evaluation time from 3 days to 15 minutes. Furthermore, the performance evaluation of HPG-based paste filling materials is convenient and technically simple to conduct, allowing for timely on-site guidance on the dynamic adjustment of quicklime dosage to avoid safety and environmental incidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0019] Figure 1 This is a flow chart of the rapid quantitative evaluation method for the comprehensive performance of HPG-based paste filling materials.

[0020] Figure 2 Figure 1 shows the regression analysis results of the comprehensive performance and pH value of the HPG-based paste filling material in Example 1. (a) is the mathematical calculation model for pH value and water bleeding rate; (b) is the mathematical calculation model for pH value and initial setting time and final setting time; (c) is the mathematical calculation model for pH value and compressive strength; and (d) is the mathematical calculation model for pH value and total phosphorus concentration and fluoride concentration.

[0021] Figure 3 Figure 2 shows the regression analysis results of the comprehensive performance and pH value of the HPG-based paste filling material in Example 2. (a) is the mathematical calculation model for pH value and water bleeding rate; (b) is the mathematical calculation model for pH value and initial setting time and final setting time; (c) is the mathematical calculation model for pH value and compressive strength; and (d) is the mathematical calculation model for pH value and total phosphorus concentration and fluoride concentration. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0023] Example 1 A method for rapid quantitative evaluation of the comprehensive performance of HPG-based paste filling materials comprises the following steps: (1) Using the same batch of HPG, HPG-based paste filling material slurries were prepared in the laboratory (the slurry mass concentration and the total tailings content of the HPG-based paste filling material slurry prepared in the laboratory were determined based on the slurry mass concentration and the total tailings content of the HPG-based paste filling material slurry at the production site. In this embodiment, the slurry mass concentration was 60% and the total tailings content was 0%). The slurry mass concentration was fixed at 60%, the total tailings content was 0%, and the quicklime content was 0%, 0.5%, 1%, 1.5%, 2% and 3% of the HPG mass, respectively, to obtain HPG-based paste filling material slurry 1, HPG-based paste filling material slurry 2, HPG-based paste filling material slurry 3, HPG-based paste filling material slurry 4, HPG-based paste filling material slurry 5 and HPG-based paste filling material slurry 6.

[0024] (2) Then, a portion of each HPG-based paste filling material slurry was taken and allowed to stand for 10 minutes. The filling material slurry was then filtered using a vacuum water circulation pump. The filter medium was a 0.45-μm filter membrane and the filtration time was 1 minute. The pH value of the filtrate under the corresponding quicklime dosage conditions was measured and shown in Table 1.

[0025] At the same time, the remaining HPG-based paste filling material slurry was used to carry out a comprehensive performance test of the filling material to determine the water bleeding rate, setting time, strength, and total phosphorus content and fluoride content of the leachate. Figure 2 .

[0026] The water bleeding rate test is to pour the HPG-based paste filling slurry into a 500 ml beaker and let it stand. The amount of water exuded is measured every 5 minutes. When the amount of water exudation decreases significantly, it is measured every 1 minute. The water bleeding rate is calculated based on the total amount of water exuded. The setting time experiment is carried out in accordance with the national standard GB / T 1346-2011, and the setting time includes the initial setting time and the final setting time.

[0027] The strength test is carried out in accordance with the industry standard JGJ / T 70-2009, and refers to the uniaxial compressive strength of the HPG-based filling specimen after curing for 3 days under standard curing conditions.

[0028] The phosphorus and fluoride leaching experiment was carried out in accordance with the industry standard HJ 557-2010. The total phosphorus was determined by ammonium molybdate spectrophotometry, and the fluoride was determined by ion selective electrode method.

[0029] Each group of filling material performance measurement experiments was carried out three times in parallel, and the experimental results were the average of the three data.

[0030] (3) The regression analysis method was used to construct a mathematical calculation model for the performance index of HPG-based paste filling materials with respect to pH value, see Figure 2 Specifically: The mathematical calculation model formula of pH value and water seepage rate is y=17.81-0.0596*e （0.4304*x） , R 2 =0.9777, where y is the water seepage rate and x is the pH value.

[0031] The mathematical calculation model formula of pH value and initial setting time is y=15.95+2.06*x-0.2566*x 2 , R 2 =0.9804, where y is the initial setting time and x is the pH value.

[0032] The mathematical calculation model formula of pH value and final setting time is y=27.64+1.77*x-0.3041*x 2 , R 2 =0.9835, where y is the final setting time and x is the pH value.

[0033] The mathematical calculation model formula of pH value and compressive strength is y=0.2293+0.000046*e （0.8985*x） , R 2 =0.9911, where y is the compressive strength and x is the pH value.

[0034] The mathematical calculation model formula of pH value and total phosphorus concentration is y=89.06-12.33*x+0.4185*x 2 , R 2 =0.9992, where y is the total phosphorus concentration and x is the pH value.

[0035] The mathematical calculation model formula of pH value and fluoride concentration is y=68.41-6.81*x+0.1649*x 2 , R2 =0.9894, where y is the fluoride concentration and x is the pH value.

[0036] (4) HPG-based paste filling slurry was directly taken from the production site. After standing for 10 minutes, the pH value of the slurry was quickly measured to be 11.79. The performance index parameters of the HPG-based paste filling material were obtained by substituting them into the calculation model obtained in step (3): water bleeding rate 8.28%, initial setting time 4.57 hours, final setting time 6.24 hours, strength 2.06 MPa, total phosphorus concentration 1.86 mg / L, and fluoride concentration 11.04 mg / L. In addition, part of the filling slurry was taken to conduct experiments using the method described in step (2). The actual performance indicators of the filling slurry were: water bleeding rate 7.46%, initial setting time 5.15 hours, final setting time 6.74 hours, strength 1.83 MPa, total phosphorus concentration 2.07 mg / L, and fluoride concentration 10.49 mg / L. The errors were within 5% to 13%, indicating that the method described in the present invention has high accuracy in evaluating the performance indicators of filling materials.

[0037] (5) A mine requires that the performance indicators of the filling material meet the following requirements: water bleeding rate less than 5%, final setting time less than 3 hours, uniaxial compressive strength more than 2 MPa, total phosphorus concentration less than 0.5 mg / L, and fluoride concentration less than 10 mg / L. However, according to the results of step (4), many performance indicators failed to meet the filling requirements. Therefore, considering that there is still a large gap with the required index values, the quicklime content is increased by 0.5%. When the quicklime content is increased by 0.5%, the pH is 12.31, and many indicators still cannot meet the requirements. The quicklime content of the mine is further increased by 1%, and the pH is increased to 12.56. The water bleeding rate is 4.54%, the initial setting time is 1.34 hours, the final setting time is 1.90 hours, the strength is 3.89 MPa, the total phosphorus concentration is 0.22 mg / L, and the fluoride concentration is 8.89 mg / L. All the performance indicators of the filling material can meet the mine's requirements.

[0038] Table 1 Example 2 A method for rapid quantitative evaluation of the comprehensive performance of HPG-based paste filling materials comprises the following steps: (1) Using the same batch of HPG, HPG-based paste filling material slurries were prepared in the laboratory (the slurry mass concentration and the whole tailings content of the HPG-based paste filling material slurry prepared in the laboratory were determined based on the slurry mass concentration and the whole tailings content of the HPG-based paste filling material slurry at the production site. In this embodiment, the slurry mass concentration was 69%, and the mass ratio of the whole tailings to HPG was 60%). The slurry mass concentration was fixed at 69%, the mass ratio of the whole tailings to HPG was 60%, and the quicklime content was 0%, 0.5%, 1%, 1.5%, 2%, and 3% of the HPG mass, respectively, to obtain HPG-based paste filling material slurry 1, HPG-based paste filling material slurry 2, HPG-based paste filling material slurry 3, HPG-based paste filling material slurry 4, HPG-based paste filling material slurry 5, and HPG-based paste filling material slurry 6.

[0039] (2) Then, a portion of each HPG-based paste filling material slurry was taken and allowed to stand for 10 minutes. The filling material slurry was then filtered using a vacuum water circulation pump. The filter medium was a 0.45-μm filter membrane and the filtration time was 1 minute. The pH value of the filtrate under the corresponding quicklime dosage conditions was measured and shown in Table 1.

[0040] At the same time, the remaining HPG-based paste filling material slurry was used to carry out a comprehensive performance test of the filling material to determine the water bleeding rate, setting time, strength, and total phosphorus content and fluoride content of the leachate. Figure 3 .

[0041] The water bleeding rate test is to pour the HPG-based paste filling slurry into a 500 ml beaker and let it stand. The amount of water exuded is measured every 5 minutes. When the amount of water exudation decreases significantly, it is measured every 1 minute. The water bleeding rate is calculated based on the total amount of water exuded. The setting time experiment is carried out in accordance with the national standard GB / T 1346-2011, and the setting time includes the initial setting time and the final setting time.

[0042] The strength test is carried out in accordance with the industry standard JGJ / T 70-2009, and refers to the uniaxial compressive strength of the HPG-based filling specimen after curing for 3 days under standard curing conditions.

[0043] The phosphorus and fluoride leaching experiment was carried out in accordance with the industry standard HJ 557-2010. The total phosphorus was determined by ammonium molybdate spectrophotometry, and the fluoride was determined by ion selective electrode method.

[0044] Each group of filling material performance measurement experiments was carried out three times in parallel, and the experimental results were the average of the three data.

[0045] (3) The regression analysis method was used to construct a mathematical calculation model for the performance index of HPG-based paste filling materials with respect to pH value, see Figure 3 Specifically: The mathematical calculation model formula of pH value and water seepage rate is y=13.08-0.0900*e （0.3785*x） , R 2 =0.9515, where y is the water seepage rate and x is the pH value.

[0046] The mathematical calculation model formula of pH value and initial setting time is y=23.68+1.06*x-0.2292*x 2 , R 2 =0.9904, where y is the initial setting time and x is the pH value.

[0047] The mathematical calculation model formula of pH value and final setting time is y=46.07-1.73*x-0.1455*x 2 , R 2 =0.9962, where y is the final setting time and x is the pH value.

[0048] The mathematical calculation model formula of pH value and compressive strength is y=0.1574+0.000006*e （1.03*x） , R 2 =0.9841, where y is the compressive strength and x is the pH value.

[0049] The mathematical calculation model formula of pH value and total phosphorus concentration is y=99.50-15.34*x+0.5907*x 2 , R 2 =0.9995, where y is the total phosphorus concentration and x is the pH value.

[0050] The mathematical calculation model formula of pH value and fluoride concentration is y=73.68-8.98*x+0.2989*x 2 , R 2 =0.9898, where y is the fluoride concentration and x is the pH value.

[0051] (4) HPG-based paste filling slurry was directly taken from the production site. After standing for 10 minutes, the pH value of the slurry was quickly measured to be 12.13. The performance index parameters of the HPG-based paste filling material were obtained by substituting them into the calculation model obtained in step (3): water bleeding rate 4.20%, initial setting time 2.81 hours, final setting time 3.68 hours, strength 1.76 MPa, total phosphorus concentration 0.34 mg / L, and fluoride concentration 8.73 mg / L. In addition, part of the filling slurry was taken to conduct experiments using the method described in step (2). The actual performance indicators of the filling slurry were: water bleeding rate 4.71%, initial setting time 3.06 hours, final setting time 4.14 hours, strength 1.62 MPa, total phosphorus concentration 0.31 mg / L, and fluoride concentration 9.39 mg / L. The errors were within 7% to 12%, indicating that the method described in the present invention has high accuracy in evaluating the performance indicators of filling materials.

[0052] (5) A mine requires that the performance indicators of the filling material meet the following requirements: water bleeding rate less than 5%, final setting time within 5 hours, uniaxial compressive strength greater than 1.5 MPa, total phosphorus concentration less than 0.5 mg / L, and fluoride concentration less than 10 mg / L. According to the results of step (4), many performance indicators can meet the filling requirements.

[0053] While various embodiments of the present invention have been described above, the foregoing description is intended to be illustrative, non-exhaustive, and not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or improvements to existing technologies, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for rapid quantitative evaluation of the comprehensive performance of hemihydrate phosphogypsum filling materials, characterized by: The steps include: (1) Using the same batch of hemihydrate phosphogypsum, hemihydrate phosphogypsum-based paste filling material slurry was prepared in the laboratory. The slurry mass concentration and the total tailings content were fixed. The quicklime content was adjusted within the range of 0% to 3% based on the mass of hemihydrate phosphogypsum. (2) Then, a portion of the hemihydrated phosphogypsum-based paste filling material slurry was taken and allowed to stand for 10 minutes, and then vacuum filtered to measure the pH value of the filtrate under the corresponding quicklime dosage conditions; at the same time, the remaining hemihydrated phosphogypsum-based paste filling material slurry was taken to carry out a filling material comprehensive performance test to measure the filling material bleeding rate, setting time, strength, and total phosphorus content and fluoride content of the leachate; (3) Using regression analysis method to construct a mathematical calculation model of the performance indicators of hemihydrate phosphogypsum-based paste filling materials with respect to pH value; (4) Take the semi-hydrated phosphogypsum-based paste filling slurry directly from the production site, let it stand for 10 minutes, and then quickly measure the pH value of the slurry. Substitute it into the calculation model obtained in step (3) to obtain the performance index parameters of the HPG-based paste filling material.

2. The method for rapid quantitative evaluation of comprehensive performance of hemihydrate phosphogypsum filling materials according to claim 1, characterized in that: The mass proportion of soluble P2O5 in the hemihydrate phosphogypsum is 0.3%~0.8%, and the mass proportion of soluble F - The mass share is 0.2%~0.35%.

3. The method for rapid quantitative evaluation of comprehensive performance of hemihydrate phosphogypsum filling materials according to claim 1, characterized in that: The effective calcium oxide content of the quicklime is not less than 80%.

4. The method for rapid quantitative evaluation of comprehensive performance of hemihydrate phosphogypsum filling materials according to claim 1, characterized in that: In step (2), the preparation method of the HPG-based paste filling material slurry includes: adding hemihydrate phosphogypsum, quicklime, whole tailings and water into an iron container at the same time, and then stirring for 3 minutes.

5. The method for rapid quantitative evaluation of comprehensive performance of hemihydrate phosphogypsum filling materials according to claim 1, characterized in that: In the step (2), the mass concentration of the hemihydrate phosphogypsum-based paste filling material slurry is 59% to 71%; and the mass percentage of the whole tailings is 0 to 100% based on the mass of the hemihydrate phosphogypsum.

6. The method for rapid quantitative evaluation of comprehensive properties of hemihydrate phosphogypsum filling materials according to claim 1, characterized in that: The slurry mass concentration and the whole tailings content of the semi-hydrated phosphogypsum-based paste filling material slurry directly collected from the production site are the same as those of the semi-hydrated phosphogypsum-based paste filling material slurry prepared in the laboratory.

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