New Zealand startup Avertana has signed a deal with a Chinese steelmaker that puts it on the road to commercialising its titanium recycling technology. The deal comes after nine years of research and development into extracting titanium dioxide from slag heaps created by steel manufacturing.Auckland-based Avertana signed a deal on June 28 in China with the Tranvic Group to refine slag by-products into high-value titanium dioxide pigment. The pigment is used in paints and a range of chemical and mineral products used for water treatment, fertiliser, papermaking and building materials.