The influence of hydrothermal salt and tailing biocementation covered by fiber covering in an arid region

Metal tailings contain a variety of toxic heavy metals and have potential environmental risks owing to long-term open.piling. This study investigated the influence of a plant fiber covering on the distributions of tailings water, heat, and tailing biocementation for improved regulation of tailings pollution by microbial-induced calcium precipitation. Simulation and field tests were conducted to investigate different compositions covering (jute, straw, coconut, palm) and different specifications (300 g m −2 , 500 g m −2 , 700 g m −2 , and 900 g m −2 ) of the plant fiber covering. The results show that the plant fiber blanket cover can: (1) reduce the tailing temperature by 0.9–10.6 °C, the daily temperature difference by 0.5–6.2 °C and the daily variation range by 0–10.5 °C, among which the 900 g m −2 straw fiber blanket (D9) can reduce the temperature by 4.6–10.6 °C, the daily temperature difference by 1.7–6.2 °C and the daily variation range by 2.7–6.8 °C; (2) improve the water retention of tailings and reduce evaporation by 37.0–71.3%, in which D9 can reduce evaporation by 71.3%; (3) increase thickness 0.15–2.53 mm, shear strength 0.34–1.04 kg cm −2 and hardness 3.60–15.40 N, which can effectively inhibit dust deposition, and D9 can increase 2.53 mm, shear strength 1.04 kg cm −2 and hardness 15.40 N of the biological cementing layer. These findings suggest that the plant fiber covering enhanced the inhibition of diffuse tailings pollution by microbial-induced calcium precipitation technology, with D9 showing the optimal effect. This study can provide theoretical support for the application of microbial-induced calcium precipitation technology to regulate diffusion of tailings pollution in dry areas. • Plant fiber blanket can reduce tailing temperature, diurnal temperature difference and diurnal variation range. • Plant fiber blanket covering can improve water retention of tailings and reduce evaporation. • Biogenic calcite filled the interstices of tailings particles and cemented the adjacent particles. • The covering of plant fiber blanket can increase the thickness, shear strength and hardness of bio-cement layer, and effectively inhibit dust.