Industry Background

The Chinese standard YS/T 298-2024 “High-Titanium Slag” was officially released on October 24, 2024, and will come into force on May 1, 2025.
The revision reflects the latest changes in China’s titanium industry, including shifts in resource availability, advances in production technology, and growing requirements for green and sustainable manufacturing.

In nature, titanium minerals mainly exist in oxide form. High-quality titanium raw materials, such as natural rutile and ilmenite placer sands, are primarily found in countries including Australia, the United States, Canada, Vietnam, India, and several coastal African nations. At the same time, primary titanium ore deposits and vanadium-titanium magnetite are more widely distributed in China, the former Soviet Union region, and South Africa.

Because most primary titanium ores contain relatively low titanium dioxide (TiO₂) content, they must undergo electric furnace smelting or other upgrading processes to raise the TiO₂ level to above 70%. Only after this enrichment can the material be used for the production of titanium tetrachloride (TiCl₄) or welding electrodes.
Currently, the industry widely recognizes low-calcium-magnesium high-titanium slag, UGS slag, synthetic rutile, and natural rutile as high-quality titanium feedstocks.

As high-grade natural rutile resources continue to decline, the global titanium resource structure has changed significantly. Today, most titanium resources are available in the form of ilmenite concentrates with 40%–50% TiO₂, which require further upgrading before industrial use. In this context, high-titanium slag and synthetic rutile have become the two main upgraded products. Among them, electric-furnace high-titanium slag accounts for more than 70% of total upgraded titanium feedstock output, making it a key raw material for titanium dioxide, sponge titanium, and other downstream titanium products.

The previous version of YS/T 298 was revised in 2015 and mainly applied to small-scale high-titanium slag furnaces and small chlorination systems in China. In recent years, however, outdated capacity has been phased out, while large-scale slag furnaces and large top-discharge chlorination systems have developed rapidly. At the same time, titanium tetrachloride production technology has improved significantly. As a result, the old standard could no longer fully meet current industry needs in terms of grade classification, chemical composition control, particle size requirements, and testing methods, making this revision necessary.

Key Revisions in the New Standard

1. Optimized Grade System

As high-quality titanium ore resources become increasingly scarce, the supply of raw materials suitable for producing 94%-grade high-titanium slag has continued to decline. This has led to limited output, high costs, and reduced practical use of the TZ94 grade. Based on actual industrial demand, the revised standard removes the TZ94 grade.

At the same time, China’s reliance on imported titanium ores has gradually decreased, while chlorination technologies have become more capable of processing lower-grade slag. To better cover all high-titanium slag used in titanium tetrachloride production, the new standard adds several new grades, including TZ88-1, TZ88-2, TZ83, TZ80, TZ78, TZ76, and TZ74, greatly expanding the applicability and flexibility of the grading system.

More Precise and Practical Chemical Composition Requirements

High-titanium slag production in China mainly relies on two types of ilmenite concentrates:

Imported coastal placer ilmenite
These ores have undergone natural weathering and gravity separation, resulting in lower impurity levels, especially calcium oxide (CaO) and magnesium oxide (MgO). They are therefore more suitable for fluidized-bed chlorination processes.

Ilmenite separated from domestic vanadium-titanium magnetite
Since the original ore has not experienced natural weathering, impurity levels—particularly calcium and magnesium—are relatively higher. Slag produced from this type of ore typically has a lower TiO₂ grade and is mainly used in molten-salt chlorination processes.

To reflect these differences, the revised standard introduces low-calcium-magnesium indicators for grades such as TZ92, TZ90, TZ88, and TZ85. In addition, stricter limits are set for impurities such as SnO₂, ZrO₂, and Nb₂O₅, helping ensure more complete titanium reactions and higher recovery efficiency during chlorination.

The standard also takes into account that some chlorination processes are particularly sensitive to the content of rutile-type TiO₂. For the first time, this parameter has been formally included in the quality control system, making product evaluation more aligned with real production requirements.

Particle Size Requirements Matched to Process Needs

Different chlorination technologies have very different particle size requirements for high-titanium slag:

Fluidized-bed chlorination requires a relatively narrow particle size distribution to ensure good mixing with chlorine gas and stable fluidization.

Molten-salt chlorination generally prefers finer particles so that the slag can react more quickly with the molten bath and rising chlorine gas, reducing material settling at the bottom.

The 2015 standard provided only general particle size guidance. In the revised version, particle size requirements have been clearly refined and adjusted according to different process routes, with detailed specifications listed in Table 2 of the standard.

Updated Testing Methods Aligned with Industry Practice

To support the newly added chemical composition indicators, the revised standard fully adopts the latest version of YS/T 514 “Chemical Analysis Methods for High-Titanium Slag and Rutile” (all parts).

In addition, since previous standards did not include a method for determining rutile-type TiO₂ content in high-titanium slag, this revision introduces a validated testing method. The method has been confirmed through experimental verification and is included as a normative appendix, significantly improving the reliability and practicality of quality testing.

Industry Impact and Conclusion

High-titanium slag is a critical intermediate material in China’s titanium industry. Its raw material sources, production processes, and quality levels directly affect the performance, service life, and environmental safety of downstream products such as titanium dioxide and sponge titanium.

The release and implementation of YS/T 298-2024 directly address changes in titanium resource structure, advances in high-titanium slag production technology, and the continued expansion of the titanium industry. By establishing a clear, unified, and practical quality standard for production, trade, and application, the new standard helps to:

• Improve the consistency and stability of high-titanium slag quality.

• Reduce communication and transaction costs between upstream and downstream partners.

• Support the titanium industry’s transition toward higher efficiency, greener production, and larger-scale operations.

Overall, this standard provides an important technical and regulatory foundation for the sustainable development of China’s titanium industry and the global titanium value chain.