Dark lines run like pencil marks across the sand of many South African beaches. Although many people think this is oil contamination, these lines are actually mineral sands and an important South African export. In areas such as Richards Bay and off the West Coast, the sand is mined for ilmenite, which contains titanium.
South Africa, which has the second largest reserves of ilmenite in the world after Australia, earns about $0.29/kg when it exports ilmenite, but pays $30/kg when it imports it back into the country as titanium metal.
Titanium dioxide, which is sourced from ilmenite, is the most widely used form of titanium. It is the white pigment found in toothpaste and sunscreens, as well as paint, and is also used to improve the taste and appearance of milk. However, the money is in the metals industry.
The Council for Scientific and Industrial Research (CSIR), in partnership with the department of science and technology, has launched a titanium-powder pilot plant at its campus in Pretoria. It is only one aspect of South Africa's ambition to beneficiate the valuable metal in the country, rather than exporting it as relatively cheap raw material, or slag.
The Titanium Centre of Competence is an umbrella organisation that co-ordinates the country's technological development, with the aim of developing and commercialising South Africa's titanium industry. Research ranges from primary metal production through to high-speed additive manufacturing, such as titanium hip joints.
The pilot plant in Pretoria aims to scale up the laboratory-proven process of creating titanium powder, which is expected to be internationally competitive as a result of cutting out a number of steps in the expensive and laborious process of making titanium metal.
"The current process for producing titanium, the Kroll process, is relatively expensive. You have huge reactors and, in the end, you have to cut them open and destroy them," said Dr Willie du Preez, the centre's director. "The reason [the metal] is so expensive is because the process is so expensive."
The plant's powder-making technique, which has been patented internationally, has been proven on a laboratory scale and cuts out a number of the steps involved in producing the metal. "[It] will produce titanium at significantly lower cost," Du Preez said.
Incredibly strong
A huge room on the CSIR campus is filled with shiny metal vats and trays. Dr Dawie van Vuuren, who heads up the plant, shows me a cylindrical keg in which the powder was produced during the laboratory phase. It has the diameter of a handspan. "It took about a week to make a kilogram of the powder," he said. The new facility will produce two kilograms an hour continuously.
Du Preez said the pilot plant was a test facility to determine whether and how the process could be scaled up to a commercial level.
However, the South African team is not the only one in the world trying to find cheaper ways to produce titanium, which is in demand because it is incredibly strong and light.
South Africa's titanium programme cost about R200-million, he said. The plant itself cost about R50-million. Both Du Preez and Dr Oliver Damm, the commercial director at the Titanium Centre of Competence, said there were possible commercial financiers and operators, but they could not name them because agreements had not yet been signed. Once the pilot plant had ironed out possible bugs in the process, the next step would be a demonstration plant, then a commercial plant, Damm said.
There has been a great deal of interest in South Africa's titanium ambitions, particularly from the aerospace industry. Project Aeroswift, which is part of the titanium strategy and a partnership between the CSIR's National Laser Centre and local aircraft parts manufacturer Aerosud, aims to develop additive manufacturing techniques and the world's largest 3D printer. In the manufacturing process, titanium powder would be melted into super-thin cross-sections of an object, which would then be welded together into the desired shape.
This feeds into the choice of titanium powder as the best way to produce titanium metal. Said Damm: "As far as the aerospace industry is concerned, the products are costly because of the refining process. Because of the nature of the parts [which are specialised and complex], you end up creating metal chips [as you cut the desired shape out of a block of metal]. You can use up to 100kg of material for a 2.5kg-5kg part. This is where the trend towards titanium powder comes in. You reduce waste material and machining times. That's what the original equipment manufacturers are interested in," he said.
The key to South Africa becoming a global player in this field is being able to produce the titanium powder in-house, rather than importing it.
"We are confident the process works," said Damm. "We are not pushing the boundaries of engineering, but there is still work to be done."