Iron ore tailings (IOTs) are byproducts of the iron mining industry that have gained significant attention in recent years due to their potential for comprehensive utilization. This study investigates how blending steel slag with IOTs (a siliceous raw material) instead of lime (a calcareous raw material) affects slurry foaming properties, mechanical properties, and reaction mechanisms of autoclaved aerated concrete (AAC). The results indicate that the sample containing 24% IOT content exhibited the best performance, with a bulk density of 640 kg/m³ and a compressive strength of 4.1 MPa. In addition, IOTs not only served as a filling material but also acted as a carrier for the growth of tobermorite. Tobermorite was combined with the unreacted iron tailing and its neighboring tobermorite to form a cohesive whole. This study provides valuable insights into the potential for IOTs to improve the properties of AAC when used as a supplementary material. The findings also suggest that the comprehensive utilization of IOTs and other industrial byproducts have the potential to contribute to the development of sustainable building materials and reduce the environmental impact of the mining industry.

Limestone calcined clay cement (LC³) presents a promising alternative material due to its reduced CO₂ emissions and superior mechanical properties compared to traditional Portland cement (PC). This study investigates the synergistic effect of calcined coal-series kaolinite (CCK) and limestone (LS) on the hydration behavior of cement, specifically focusing on varying mass ratios. The combination of CCK and LS promotes the formation of strätlingite and carboaluminates, which enhances early-age strength development. Additionally, the inclusion of CCK facilitates the formation of carboaluminates during later stages of hydration. After 56 days of hydration, the content of carboaluminates is over 10%wt. This stimulation of secondary hydration products significantly refines the evolution of pore structure, with the harmful large pores gradually transformed into harmless medium pores and gel pores, leading to marked improvements in compressive strength from 7 to 28 days. Replacing 45% PC with CCK and LS at mass ratio of 7 to 2, the compressive strength of blends reaches 47.2 MPa at 28 days. Overall, the synergistic interaction between CCK and LS presents unique opportunities to minimize the CO₂ footprint of the cement industry without compromising early and long-term performance.

With the vigorous development of the 5G industry, the characteristic hazardous waste, spent coppery etchant, was also produced in large quantities. In recent years, there are many companies that have begun to collect spent coppery etchant for the purpose of producing recycled products, such as copper sulfate, copper oxide, basic copper chloride, and copper powder, which often contain large amounts of heavy metals. However, due to the lack of relevant standards and applicable regulatory measures, some of the recycled products flow to the feed processing industry and even to the food processing industry. This study investigated the pollution status of heavy metals in recycled products of spent coppery etchant and evaluated the impact of recycled products exposure on human health. The results showed that the content of Zn was the highest, which was 21 times higher than the corresponding standard limit. Human health risk assessment indicated that the hazard quotients of As account for 87.5% of the entire HI value, while the average carcinogenic risk values of As for copper sulfate, copper oxide, basic copper chloride, and copper powder are 1.09 × 10⁻⁵, 3.19 × 10⁻⁵, 1.29 × 10⁻⁵, 7.94 × 10⁻⁶, respectively. Meanwhile, suggestions on the supervision of recycled products and the concentration limits of heavy metals in recycled products were put forward.

The pesticide industry is one of the primary industries with large and complex VOC emissions. The present study examined the emission characteristics and whole-process control of VOCs in the pesticide industry in China by reviewing pollutant discharge permits, questionnaires, and site investigations. After evaluating the effectiveness of current treatment technologies, the potential of VOC emission reduction in China was analyzed. The results indicate that there are 41 key VOC substances in the pesticide industry that should be given considerable attention. Among treatment facilities, incineration was found to be the most efficient technology, with a removal rate of 53–98% and coverage rate of 23.3%. Multistage absorption–adsorption is a universal technology that had a removal rate of 35–95% and coverage rate of 64.14%. Multistage absorption was used most frequently, with a coverage rate of 71.99%, but its removal rate was between 16 and 85%. Pesticide factories were divided into three levels according to their pollution control capability; the comprehensive removal rates of benchmark, moderate, and poor factories were 81%, 46%, and 8%, respectively, and the emission reduction ratios for high, moderate, and low targets were 41.55%, 32.12%, and 24.32% with corresponding emission reduction costs of $0.653, $0.505, and $0.038 billion/year. The results and prospects from this study will provide support for policy development in industrial VOC emission control in China during the “14th Five-Year Plan” period.

This paper investigates the structural transformation of dicalcium silicate (C₂S) crystals brought about through boron doping. Both qualitative and quantitative analyses were conducted to explore the correspondence between boron content and the structure of dicalcium silicate. The results show that boron doping can stabilize β-C₂S and the high-temperature phase α′_H-C₂S, and the structural transformation does not involve the modulation of α′_L-C₂S. There is a corresponding relationship between the unit cells of β-C₂S and α′_H-C₂S, which can be transformed using a transformation matrix. The relationship between boron content and the content of different C₂S structures, as well as the structural expressions for β-C₂S and α′_H-C₂S, is determined using linear fitting and multivariable linear regression analysis.

This study assessed heavy metal contamination in industrial solid waste (S1, S2, S3, and S4) from the Yangtze River Delta region, employing nine risk assessment methods including total content indices (e.g., Igeo, CF) and speciation indices (e.g., ICF, GCF). Four types of industrial solid waste not classified as hazardous but containing heavy metals were analyzed. Key findings revealed significant variability in risk assessments based on chemical speciation versus total content. For example, while S1, S3, and S4 exceeded background levels, S4 showed higher mobility of Pb, Cr (VI), Cu, Ni, and As despite lower overall content. Elements like Cd and Cr (VI) exhibited discrepancies between total content and speciation-based assessments due to low background values and high toxicity. Multi-element indices (DC, RI) indicated higher pollution degrees compared to speciation indices (GCF, GRI). These results underscore the need for integrating multiple assessment methods to accurately evaluate environmental risks in judicial practices.