Gold costs were about $317 per troy ounce in 2007, but these can vary widely depending on mining type and ore quality; global mine production amounted to 2,471.1 tonnes. After initial production, gold is often subsequently refined industrially by the Wohlwill process which is based on electrolysis or by the Miller process, that is chlorination in the melt. The Wohlwill process results in higher purity, but is more complex and is only applied in small-scale installations. Other methods of assaying and purifying smaller amounts of gold include parting and inquartation as well as cupellation, or refining methods based on the dissolution
Five Ways to Save the World ocean acidification. Since the last two methods would remove carbon dioxide, they could in theory reduce both global warming and ocean acidification. Five Ways to Save the World Five Ways to Save the World is a British documentary film on environmental issues related to climate change, released in 2006. The film was made by Karen O'Connor, for the big screen and was shot in the English language to reach an international audience. It includes interviews with five environmental scientists and experts including Paul Crutzen, James Roger Angel, John Latham, Ian Jones, and Klaus Lackner. The "five ways" proposed are geoengineering