Standards Development

The iron and steel industry is characterized by high energy consumption, high emissions, large volumes of solid waste, and high carbon emission intensity. Pollution abatement and carbon reduction are therefore an inevitable pathway for the sector to achieve green and low-carbon development.

The utilization of steel slag, a bulk solid waste generated during iron and steel production, requires coordination with downstream industries and remains one of the most challenging aspects of waste management, significantly constraining the industry's sustainable development. Nevertheless, steel slag possesses carbonation consolidation properties and is capable of sequestering between 70 and 105 kg of CO₂ per tonne. This represents a global annual carbon sequestration potential of approximately 2.1 to 3.15 million tonnes, making it a significant opportunity for industrial carbon emission reduction.

Globally, steel slag carbonation technologies are advancing rapidly, with an increasing number of large-scale demonstration projects being implemented. Steel slag carbon-sequestering products, including carbonated steel slag aggregates and carbon-fixing construction materials, have gradually achieved large-scale production and are entering international markets as low-carbon industrial products. While these products are marketed with claims of carbon dioxide sequestration benefits, the absence of a unified testing standard makes it difficult for buyers, regulatory authorities, and carbon trading platforms to verify the actual amount of carbon sequestered.

This lack of standardization creates a risk of "greenwashing" disputes and market trust issues, highlighting the urgent need for an internationally recognized testing method that can provide consistent and comparable conformity assessment. Accurate determination of the amount of CO₂ fixed by steel slag is essential for evaluating the carbon sequestration efficiency of different technologies, promoting the development of low-carbon solutions, and supporting the achievement of global carbon reduction goals.

At present, there is no internationally harmonized standard for determining the content of carbon dioxide fixed through steel slag carbonation. Technical differences in the methods adopted by various countries result in poor comparability of data, directly hindering global carbon trading and the international diffusion of technology. As the cross-border trade of steel slag carbon-sequestering products continues to expand, the absence of a standardized testing method also prevents international mutual recognition of carbon sequestration claims. This situation can create new green trade barriers and restrict market access for low-carbon products, as well as impede the transnational transfer of carbon credits.

Existing standards also have limitations relating to sample pretreatment, interference elimination, and applicability, making them unsuitable for direct use in steel slag carbonation scenarios. Furthermore, the current international standards framework lacks a method for the separate determination of free carbon and fixed carbon in steel slag, resulting in reduced accuracy when assessing carbon sequestration efficiency.

In summary, it is recommended that an international standard for the determination of carbon dioxide content fixed by steel slag carbonation be developed. Such a standard should build upon proven technical methodologies and comprehensive engineering data to address the existing gap in international standardization. Once established, it would provide a unified benchmark for testing carbon-sequestering steel slag products in cross-border trade, customs verification of carbon data, and green product certification. This would help eliminate methodological inconsistencies and trade barriers between countries.

The international implementation of such a standard would significantly improve the credibility, transparency, and comparability of carbon sequestration data across the global steel industry. It would also establish a consistent metrology framework throughout the steel slag carbon sequestration value chain, support the achievement of the Paris Agreement's global temperature goals, promote the orderly development of the global steel carbon sequestration industry, and accelerate the worldwide transition toward greener and lower-carbon industrial systems.