Tungsten
H.C. Starck Tungsten Powders GmbH (Goslar, Germany; www.hcstarck.com), a wholly owned subsidiary of Vietnam listed Masan High Tech Materials, has developed a new process for high-pressure reverse osmosis in the production of tungsten chemicals that significantly reduces energy consumption and CO2 emissions compared to conventional processes. To achieve this, the Technology and Innovation department cooperated closely with process specialist OSMO Membrane Systems GmbH (Korntal-Münchingen, Germany; www.osmo-membrane.de). H.C. Starck is already using the process at its Goslar site for the concentration of ammonium metatungstate (AMW) solutions on an industrial scale.
In the production of AMW, a very dilute solution is first obtained from ammonium paratungstate (APW), which then has to be highly concentrated. This is traditionally done by evaporation, which is energy intensive. With the new patent-pending process, the solution is pressed under high pressure through a semi-permeable membrane. The membrane-based approach reduces energy consumption by more than 95% at a production volume of around 1,000 ton/yr of AMW, says the company.