In the heart of China’s Hunan province, researchers at Central South University are turning mining waste into a valuable resource, potentially revolutionizing the construction and energy sectors. Jielin Li, a leading researcher from the School of Resources and Safety Engineering, has been exploring the use of titanium-extracted tailings to create composite cementitious materials for mine backfilling. This innovative approach not only addresses environmental concerns but also promises to enhance the strength and durability of backfill materials, offering significant commercial benefits.
The study, published in the journal *Case Studies in Construction Materials* (translated as “建筑材料案例研究”), focuses on the physical and mechanical properties of backfill materials made from titanium-extracted tailings composite cementitious materials (TCM) and gold mine full tailings (GMT). The research team prepared mine backfill slurries and conducted extensive tests to analyze their uniaxial compressive strength, fluidity, bleeding rate, and pore distribution.
One of the key findings is that the compressive strength of TCM backfill specimens increases with the curing period and exhibits a positive correlation with the cement-sand ratio. “The compressive strength growth rate of TCM backfill specimens gradually increases with the extension of the curing period,” Li explained. “Under the same curing time, the compressive strength of TCM backfill specimens exhibits an overall positive correlation with the cement-sand ratio.”
The study also revealed that the porosity of TCM backfill specimens ranges between 14% and 25%, with decreasing cement-sand ratio, both the quantity and size of internal pores in backfill specimens progressively increased. This finding is crucial for understanding the long-term stability and performance of backfill materials in mining operations.
Moreover, the research team discovered that a 70% concentration TCM slurry demonstrated excellent fluidity with a maximum of 610 mm, and its bleeding performance is better than that of cement group. This enhanced fluidity can significantly improve the efficiency of backfilling operations, reducing costs and increasing productivity.
The hydration mechanism of the TCM full tailings backfill system was also analyzed using Nuclear Magnetic Resonance (NMR) and Scanning Electron Microscopy (SEM). The results showed that the hydration reaction produces hydration products mainly composed of calcium silicate hydrate (C-S-H) gel and ettringite (AFt). “In the later stages of the hydration reaction, the quantity of hydration products increases rapidly, resulting in a more compact structure of the backfill material,” Li noted.
The implications of this research are far-reaching. By utilizing titanium-extracted tailings, mining companies can reduce their environmental footprint while also improving the quality of backfill materials. This innovative approach can lead to more stable and durable backfill structures, enhancing the safety and efficiency of mining operations.
Furthermore, the enhanced fluidity and strength characteristics of TCM backfill materials can have significant commercial impacts for the energy sector. As the demand for renewable energy sources continues to grow, the need for stable and efficient mining operations becomes increasingly important. The use of TCM backfill materials can help meet this demand by providing a more sustainable and cost-effective solution for mine backfilling.
In conclusion, the research conducted by Jielin Li and his team at Central South University represents a significant advancement in the field of mine backfilling. By turning mining waste into a valuable resource, this innovative approach offers a sustainable and cost-effective solution for the construction and energy sectors. As the demand for renewable energy sources continues to grow, the use of TCM backfill materials can play a crucial role in meeting this demand while also reducing the environmental impact of mining operations.