CN-117491224-B - Method for determining particle size and concentration of gangue slurry based on conveying distance

Abstract

The invention discloses a method for determining the particle size and concentration of gangue slurry based on a conveying distance, which is implemented according to the following steps of firstly, calculating the conveying time according to the furthest conveying distance and a critical flow rate, secondly, performing bleeding rate long-time variation experiments with different concentrations and different upper limit particle sizes according to the first step, determining the upper limit particle size and a slurry forming concentration range, thirdly, performing slump and expansion degree tests according to the upper limit particle size and the slurry forming concentration range determined in the second step, and calculating a gravity gradient, thirdly, if the gravity gradient meets the flowability requirement, the slurry forming concentration range is a final concentration range, and if the gravity gradient does not meet the flowability requirement, reducing the upper limit particle size and repeating the third step until the concentration meeting the flowability requirement under the particle size appears as the final concentration range. The method for determining the particle size and the concentration of the gangue slurry based on the conveying distance reduces the energy consumption of gangue crushing and pulping, reduces the running cost of a slurry filling system and improves the popularization applicability of the technology.

Inventors

• ZHU LEI
• LI JUAN
• QIU FENGQI
• HE ZHIWEI
• ZHANG PENG
• Sheng Fengtian
• SONG TIANQI
• LIU CHENGYONG
• GU WENZHE
• ZHAO MENGYE
• WU YUYI
• SUN JUNYAN
• LIU ZHICHENG
• PAN HAO

Assignees

• 中煤能源研究院有限责任公司

Dates

Publication Date

20260512

Application Date

20231101

Claims (3)

1. 1. The method for determining the particle size and the concentration of the gangue slurry based on the conveying distance is characterized by comprising the following steps of: step 1, calculating conveying time t according to the farthest conveying distance and the critical flow rate; step 2, performing long-time variation experiments of bleeding rates with different concentrations and different upper limit particle diameters according to the step 1, and determining the upper limit particle diameters and the slurrying concentration ranges under the upper limit particle diameters; step 3, carrying out slump and expansion degree tests according to the upper limit particle size determined in the step 2 and the slurry concentration range under each upper limit particle size, and calculating the gravity gradient; Step 4, if the gravity gradient meets the fluidity requirement, the slurry forming concentration range is a final concentration range, if the gravity gradient does not meet the fluidity requirement, the upper limit particle size is reduced, and the step 3 is repeated until the concentration meeting the fluidity requirement under the particle size is generated, and the final concentration range is used; The step 1 specifically comprises the following steps: Step 1.1, taking the furthest filling position of the gangue slurry filling system as the furthest conveying distance L max under the filling working condition; step 1.2, calculating to obtain the minimum flow velocity V min of the gangue slurry according to the characteristics and working conditions of the conveyed materials; Step 1.3, calculating the conveying time t according to the farthest conveying distance L max and the critical flow velocity V min , wherein t=L max /V min ; The minimum flow velocity V min of the gangue slurry in the step 1.2 has the following calculation formula: V min = ; Wherein V min is critical flow rate, the unit is m/s, ρ s is gangue powder density, the unit is kg/m 3 ;ρ h is water density, the unit is kg/m 3 ;C QV is solid-liquid two-phase flow volume concentration, and D is pipeline diameter, the unit is m; The step 2 specifically comprises the following steps: 2.1, testing the long time not less than 1.3t, testing the concentration range to be 60% -80%, changing the gradient to be 5%, and performing a bleeding rate long-time change experiment when the upper limit particle size range is 0.6 mm-5 mm; Step 2.2, analyzing bleeding rate change rules according to bleeding rate experimental results obtained in the step 2.1, and determining upper limit particle sizes and slurry forming concentration ranges under the upper limit particle sizes according to bleeding rate indexes; the gravity gradient in the step 3 is as follows: i= ; Wherein i is the gravity gradient, In order for the slump to be good, Is the degree of expansion.
2. 2. The method for determining the grain size and the concentration of the gangue slurry based on the conveying distance according to claim 1, wherein the bleeding rate index in the step 2.2 is that the gangue slurry is considered to be in a stable state at the moment when the bleeding rate is not more than 4%.
3. 3. The method for determining the particle size and the concentration of the gangue slurry based on the conveying distance according to claim 1, wherein the fluidity requirement in the step 4 is that the gravity gradient is not more than 0.4.

Description

Method for determining particle size and concentration of gangue slurry based on conveying distance Technical Field The invention belongs to the technical field of filling of coal mine gangue slurry, and relates to a method for determining the particle size and concentration of the gangue slurry based on a conveying distance. Background Along with the continuous promotion of ecological civilization construction, the gangue slurry filling is used as a large-scale, high-efficiency and low-cost gangue disposal method, and the popularization range is gradually enlarged. In the technical application process, how to ensure the long-distance stable delivery of the slurry and the diffusion performance of the slurry in the goaf directly influences the stability and the filling efficiency of the filling system. Earlier studies showed that the smaller the particle size, the higher the slurry stability, the less likely to segregate, and the higher the concentration, the higher the slurry stability, the less likely to segregate. However, the improvement of the stability of the slurry also leads to the increase of the conveying resistance, and the diffusion distance in the goaf is limited, so that the filling effect is affected. In engineering design, in order to ensure stable operation of the system, the particle size and concentration parameter values are relatively conservative, and are all values according to static conditions, and factors such as time, conveying distance and the like are not considered. Therefore, in order to further reduce the system cost according to the specific filling working condition, the invention proposes to further optimize the particle size and grading of the gangue slurry by taking the conveying distance and the conveying time as one of the influencing factors for determining the particle size and concentration parameters. Disclosure of Invention The invention aims to provide a method for determining the particle size and concentration of gangue slurry based on a conveying distance, which has the characteristics of reducing crushing pulping energy consumption and reducing slurry filling operation cost. The technical scheme adopted by the invention is that the method for determining the particle size and the concentration of the gangue slurry based on the conveying distance is implemented according to the following steps: step 1, calculating conveying time t according to the farthest conveying distance and the critical flow rate; step 2, performing long-time variation experiments of bleeding rates with different concentrations and different upper limit particle diameters according to the step 1, and determining the upper limit particle diameters and the slurrying concentration ranges under the upper limit particle diameters; step 3, carrying out slump and expansion degree tests according to the upper limit particle size determined in the step 2 and the slurry concentration range under each upper limit particle size, and calculating the gravity gradient; And step 4, if the gravity gradient meets the flowability requirement, the slurry forming concentration range is a final concentration range, and if the gravity gradient does not meet the flowability requirement, the upper limit particle size is reduced, and the step 3 is repeated until the concentration meeting the flowability requirement under the particle size is reached, and the final concentration range is obtained. The invention is also characterized in that: The step 1 specifically comprises the following steps: Step 1.1, taking the furthest filling position of the gangue slurry filling system as the furthest conveying distance L max under the filling working condition; step 1.2, calculating to obtain the minimum flow velocity V min of the gangue slurry according to the characteristics and working conditions of the conveyed materials; step 1.3, calculating the conveying time t according to the farthest conveying distance L max and the critical flow velocity V min, and then t=L max/Vmin. The minimum flow velocity V min of the gangue slurry in the step 1.2 is calculated as follows: Wherein V min is critical flow rate, the unit is m/s, ρ s is gangue powder density, the unit is kg/m 3;ρh is water density, the unit is kg/m 3;CQV is solid-liquid two-phase flow volume concentration, and D is pipeline diameter, and the unit is m. The step 2 is specifically as follows: 2.1, testing the long time not less than 1.3t, testing the concentration range to be 60% -80%, changing the gradient to be 5%, and performing a bleeding rate long-time change experiment when the upper limit particle size range is 0.6 mm-5 mm; and 2.2, analyzing a bleeding rate change rule according to the bleeding rate experimental result obtained in the step 2.1, and determining an upper limit particle size and a slurry forming concentration range under each upper limit particle size according to a bleeding rate index. And 2.2, when the bleeding rate is not more than 4%, the