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NORM residues arise, among other things, when natural radionuclides accumulate through industrial processes. This occurs in Vietnam's titanium mining industry as well as in German applications ranging from drinking water treatment to the coal and natural gas industry, the zirconium industry and deep geothermal energy.

The study trip took place within the framework of the RENO-TITAN project as part of the CLIENT II programme, which is funded by the Federal Ministry of Education and Research (BMBF) and, since May 2025, by the Federal Ministry of Research, Technology and Space (BMFTR). RENO-TITAN (2023–2026) develops solutions for the safe handling of NORM residues in Vietnam's titanium industry.

KRONOS in Nordenham: From raw material to white pigment

The group first visited the KRONOS Worldwide, Inc. plant in Nordenham, a global manufacturer of the white pigment titanium dioxide. This pigment gives products such as paints, plastics and paper their high whiteness and opacity. On site, visitors saw how pure titanium dioxide is produced from the iron- and titanium containing mineral ilmenite using the sulphate process: First, iron components are dissolved out with sulphuric acid. The remaining titanium oxide hydrate is then heated to a high temperature to form pure, white titanium dioxide in crystal form. Subsequent fine grinding and targeted surface treatment finally give the pigment the desired properties for its intended use.

The circular economy concept in practice was particularly impressive: the sulphuric acid required comes from a neighbouring company and is reused several times. Iron salts produced are marketed as valuable co-products. These are used, for example, in sewage treatment plants for phosphate removal or in cement production. This coupling of material flows ensures that resources are used efficiently and waste is minimised. The plant, which has been in operation since 1969, employs 350 people and produces around 60,000 tonnes of TiO₂ per year, benefiting from its port connection. Titanium production touches on the topic of NORM because natural radionuclides from ilmenite/rutile can accumulate in processing and waste streams.

Asse II: Transparency in dealing with contaminated sites

The Asse II mine near Wolfenbüttel illustrated to the group how Germany deals with radioactive contaminated sites. In the 1960s and 1970s, low- and mediumlevel radioactive waste was stored here because the salt mine was considered safe. Today, it is known that salt water is penetrating the mine and jeopardising its stability. Germany has therefore decided to retrieve all waste, a move that is unique in the world. The transparent approach to the public was particularlyinteresting: residents are actively involved through regular information, open measurement data and citizen measuring stations. Trust is also key when dealing with NORM residues. Appropriate monitoring, operational precautions and open communication are essential – even if the radiological risks are significantly lower than in the case of Asse II

Saxony-Anhalt: From measurement to action

The fundamentals of radiation protection were explored in depth at Magdeburg Stendal University of Applied Sciences. In Germany, the natural average annual dose is around 2.1 millisieverts (mSv). Most of this is caused by the noble gas radon in the air we breathe. In addition, medical applications such as X-rays add an average of around 1.5 mSv per inhabitant, so that a person's total exposure is typically around 3.6 mSv per year. A strict limit of 1 mSv per year applies to artificial additional exposure of the population. Radon protection was also explained using examples: if the reference value of 300 becquerels per cubic metre of indoor air is exceeded, a step-by-step approach is recommended. This includes an analysis of the causes, sealing any points of entry, improving ventilation and then checking whether these measures have been successful.

In Saxony-Anhalt, NORM cases include natural gas production in the Altmark region, where radioactive deposits must be disposed of properly. Another well known example is the slag from copper slate mining in Mansfeld, the use of which in road construction and hydraulic engineering has led to locally elevated radiation levels in many places throughout Germany.

Cröbern landfill site: NORM disposal in practice

The Cröbern central landfill near Leipzig accepts certain NORM residues for final disposal—exclusively under strict conditions and in close coordination with the competent authorities of the Free State of Saxony. Radiological assessments and waste-management documentation must be provided demonstrating that the additional radiation dose to the public remains below 1 millisievert per year. Typical wastes include deposits (scale) from the natural gas industry or spent filters from water treatment. The landfill carefully inspects each delivery, monitors the emplacement, and reports to the authorities.

Eurofins IAF Radioecology: Safely binding NORM residues

In the Eurofins IAF Radioecology laboratory, experts tested how NORM residues from Vietnam can be safely fixed in binding agents. Classic Portland cement and modern geopolymers were compared as matrices. Both materials proved successful in various tests: they remained stable and safely retained the radionuclides – well below the guideline and parameter values for drinking water. While cement is inexpensive and easy to handle, geopolymers are particularly resistant to chemicals and heat.

G.E.O.S.: From the laboratory to practical application

At G.E.O.S. in Halsbrücke, the group saw how research leads to practical applications. In a pilot plant, thorium is separated from old lightweight alloys used in aerospace applications. A second project presented to the group involves the regeneration of filter materials from drinking water treatment so that they can be reused multiple times. This conserves resources and reduces waste volumes.

Conclusion

The Vietnamese delegation was very satisfied. The direct insights into industrial practice, the measurement exercises and the procedures for the safe fixation of NORM residues were particularly valuable. The knowledge gained provides applicable solution components for the titanium industry and other sectors in Vietnam where NORM residues are produced and must be managed.© Petra Schneider