Anglo-Australian miner BHP Billiton said Friday it had completed the sale of its 37 percent stake in Richards Bay Minerals to rival Rio Tinto for $1.91 billion (1.5 billion euros). BHP Billiton said the sale of its share in the South African mineral sands miner and smelting operator \"reflects the company\'s commitment to a simpler, more scalable upstream portfolio.\" Rio Tinto had already owned a 37 percent stake in RBM and managed its operations and marketed its products. BHP had triggered the sale in February when it exercised an option to sell its stake agreed during a 2009 restructuring of RBM. \"Doubling our stake in this tier one asset further strengthens Rio Tinto\'s titanium dioxide portfolio at a time when the long-term outlook remains robust,\" said Rio Tinto Diamonds & Minerals chief executive Alan Davies. In 2011, RBM had a 14 percent share in global sales of titanium dioxide feedstock, according to Rio Tinto. The mineral is used in products from sunscreens to food colourings.