In the heart of China’s industrial landscape, a pressing environmental challenge is being tackled head-on by researchers determined to turn waste into opportunity. Dr. Shenao Zhang, from the School of Minerals Processing & Bioengineering at Central South University in Changsha, is leading the charge in finding innovative ways to utilize phosphogypsum and metallurgical acidic gypsum residue, two by-products of industrial processes that have long posed environmental and spatial challenges.
Phosphogypsum, a byproduct of phosphate fertilizer production, and acidic gypsum residue, resulting from the neutralization of dirty acid, are produced in vast quantities annually. These gypsum residues not only occupy significant land resources but also pose risks of heavy-metal leakage and toxic gas release. “Accelerating the comprehensive utilization of these two types of gypsum residues is crucial for resource recycling and ecological environmental protection,” asserts Dr. Zhang.
Currently, phosphogypsum finds applications in construction, chemical industries, and agriculture, used in cement retarders, quicklime, road base materials, and soil conditioners. However, its comprehensive utilization rate remains a mere 40%, leaving substantial stockpiles untouched. The key to expanding its market potential lies in efficient impurity removal. “The key lies in the efficient removal of its impurities,” Dr. Zhang emphasizes.
On the other hand, acidic gypsum residue, laden with toxic elements like arsenic, cadmium, and lead, presents a more complex challenge. Current disposal methods focus on valuable metal recovery and solidification/stabilization, but the complex composition and low metal content hinder economic viability and industrialization.
Dr. Zhang’s research, published in the Journal of Engineering Sciences, presents a groundbreaking framework comparing phosphogypsum and acidic gypsum residues, discussing their current utilization methods, and exploring resource-utilization mechanisms. The study also delves into the fixation mechanisms for heavy metals and other pollutants, offering a comprehensive overview of the state of affairs and future prospects.
For the energy sector, the implications are significant. Efficient utilization of these gypsum residues could lead to the development of new construction materials, chemical raw materials, and soil conditioners, reducing the need for virgin resources and lowering production costs. Moreover, the stabilization of soluble phosphorus and fluorine in phosphogypsum could open up new avenues for high-value utilization, contributing to the “Double Carbon” goal and the construction of “Waste-Free Cities.”
Dr. Zhang’s research outlines several future development steps for acidic gypsum residues, including the development of green and efficient valuable metal recovery technology, exploration of synergistic use technology with other solid wastes, optimization of efficient complexing and precipitating agents, and increased attention to the longevity of gypsum slag curing bodies.
As the world grapples with the challenges of industrialization and environmental protection, Dr. Zhang’s work shines a light on the path forward. By turning waste into wealth, we can strive towards a more sustainable and prosperous future. The research published in the Journal of Engineering Sciences (工程科学学报) serves as a beacon, guiding us towards innovative solutions that benefit both industry and the environment.