Social Benefits of Thick-Gypsum-Based Self-Leveling Flooring

Social Benefits of Thick-Gypsum-Based Self-Leveling Flooring

Gypsum-based self-leveling compounds are primarily composed of cementitious materials, aggregates, and additives. The cementitious material is mainly industrial by-product gypsum, while the aggregate used is fine aggregate with a particle size range of approximately 40–120 mesh. Experimental results demonstrate that fine aggregates in this size range exhibit excellent flowability and strong particle suspension, which enhance both the flow characteristics and mechanical strength of the self-leveling compound. In selecting aggregates, priority should be given to solid waste materials such as steel slag, steel sludge, and tailings slag, thereby turning waste into valuable resources and achieving significant economic and environmental benefits.

With the development of industrial production, the volume of industrial waste has been steadily increasing. Among these, metallurgy and thermal power generation account for the largest emissions. Industrial waste is voluminous, highly diverse in type, and complex in composition, making its treatment particularly challenging. To date, only a limited number of industrial waste streams are being effectively utilized; for example, the United States and Sweden recycle steel slag, while Japan and Denmark utilize fly ash and coal slag. The majority of other industrial wastes, however, are still disposed of through passive stockpiling. Certain hazardous solid wastes are treated by landfilling, incineration, chemical conversion, microbial remediation, and, in some cases, ocean disposal. Passive stockpiling of industrial waste not only consumes vast tracts of land and results in significant waste of human and material resources, but also poses environmental risks: many industrial residues contain water-soluble substances that can leach into soil and water bodies, causing contamination. Powdery industrial wastes can be carried by wind, polluting the atmosphere, and some even emit foul or toxic odors. In addition, certain wastes can clog river channels, pollute aquatic ecosystems, impair biological growth, and pose serious threats to human health.

Industrial solid waste contains substantial recoverable resources, and the resource recovery of such waste has become a crucial means of effectively alleviating the shortage of strategic resources. For instance, recovering valuable metal components from smelting slag, tailings, and other industrial solid wastes can help compensate for deficiencies in metallic mineral resources and strengthen China’s resource security. Therefore, to address the country’s resource scarcity and reduce the pressure that resource constraints place on economic development, it is imperative to further accelerate the resource recovery of industrial solid waste and vigorously promote the circular economy. On the other hand, research into the resource utilization of China’s industrial solid waste can effectively mitigate environmental pollution.

In 2016, China’s output of desulfurization gypsum from power plants reached 95 million tonnes, and when combined with phosphogypsum and other types of chemical gypsum, total production amounted to 140 million tonnes—three times the U.S. output for the same year. In terms of comprehensive utilization, China’s rate for desulfurization gypsum in 2016 was 70%, significantly lower than Japan’s nearly 100%, Germany’s 85%, and the EU’s 88%. Notably, coastal, economically developed regions in China exhibit higher rates of comprehensive utilization of desulfurization gypsum, whereas provinces rich in natural gypsum resources such as Shanxi, Inner Mongolia, and Shaanxi, as well as less-developed western regions, show much lower utilization rates. Gypsum-based self-leveling compounds, as an important alternative to cement that can help reduce China’s carbon emissions, have benefited from the state’s vigorous promotion of the comprehensive utilization of industrial solid waste. By substituting natural gypsum with industrial by-product gypsum such as desulfurization gypsum, production costs are substantially reduced, and the associated technologies have become increasingly mature. If all desulfurization gypsum were used to produce thick-layer self-leveling gypsum construction materials and applied in areas such as underfloor heating backfill in real estate projects, it would greatly reduce the consumption of energy-intensive cement products, minimize land occupation caused by storage, and deliver significant social benefits in terms of energy conservation and emission reduction, the development of a circular economy, clean production, the achievement of zero discharge of coal-fired power plant fly ash and slag, and the building of a resource-conserving society.

Xindadi’s thick-layer self-leveling compound is a domestic innovation and currently the most suitable backfill material for underfloor heating in newly built commercial residential properties, boasting enormous market potential. As its primary raw material—hemihydrate gypsum, which accounts for 60% of the weight—can be produced from desulfurization gypsum, this product has become the largest consumer of desulfurization gypsum among all gypsum-based products in China’s building materials market. When desulfurization gypsum is processed into thick-layer self-leveling mortar and applied in real estate projects, it can be fully consumed. At the same time, this practice is of great significance for energy conservation and emissions reduction, as well as for increasing the value added of industrial by-products.

Thick-layer self-leveling compound is easy to transport and store, can be applied mechanically, and, when mixed with water, exhibits excellent fluidity and superior self-leveling properties that ensure automatic leveling. Thanks to its outstanding advantages—such as crack resistance and superior surface flatness—which traditional materials cannot match—it also allows the two conventional steps of underfloor heating backfilling and floor leveling to be combined into a single operation, thereby eliminating one step and reducing construction costs.

It is evident that deep processing of desulfurization gypsum into gypsum-based self-leveling products offers substantial profit margins and broad market prospects, making it a win-win collaboration for all parties involved. While promoting thick-layer self-leveling compounds, we will also strive to expand the market share of gypsum powder in other gypsum-based products, such as gypsum plasterboard, gypsum blocks, gypsum paper-fiber boards, skim-coat gypsum, joint-filling gypsum, and filling gypsum, employing a multi-pronged approach to maximize sales volume and profitability. In summary, if the desulfurization gypsum generated by Datang Power’s 22 coal-fired power plants were entirely utilized to produce thick-layer self-leveling compounds and other gypsum construction materials for applications such as underfloor heating backfill in the real estate sector, it would significantly reduce the consumption of energy-intensive cement products, minimize land occupation associated with storage, and deliver profound social and economic benefits in terms of energy conservation, emission reduction, circular economy development, clean production, zero discharge of coal-fired power plant waste residues, and the building of a resource-efficient society—making it a truly beneficial initiative for both the nation and the people. It can be anticipated that, once this pilot project is successfully implemented on a large scale, it will usher in a transformative shift in the application of desulfurization gypsum.