Fine characterization of pore structure of acidified anthracite based on liquid intrusion method and Micro-CT

Acidification erosion can seriously affect the pore structure characteristics of anthracite. In this paper, the low -temperature nitrogen adsorption method, mercury intrusion method, and Micro-CT scanning are used to analyze the pore structure of coal samples. The microscopic morphology and spatial distribution of coal pores are characterized by fractal dimension calculation and three-dimensional reconstruction. The results show that HCl has the highest removal efficiency of minerals in the Yuwu coal sample, which reduces the mass of coal samples by about 4%. HNO3 increases the proportion of micropore volume by 4.93%. HCl increases the proportion of mesoporous pore volume by 11.4%. Through the 3D reconstruction of coal, it is found that the mineral content in coal decreased by 48.14% after HCl dissolution, and the maximum diameter of mineral particles decreased from 173.588 mu m to 57.449 mu m. The spatial distribution of minerals is uneven, and the mineral content of coal samples decreases significantly along the direction of strong fluidity. At the same time, HCl increases the pore connec-tivity of coal samples, the pore roar increases by 56.72%, the isolated pores decrease, and the peak frequency of pore coordination number increases by 4 units, which greatly improves the transport capacity of fluid in coal matrix.

Automated summary

This paper investigates the effect of acidification erosion on the pore structure of anthracite using various methods. The results show that HCl has the highest removal efficiency of minerals, leading to improved pore structure and fluid transport capacity in coal samples.