Bioleaching is an alternative industrial process used to extract metals, such as copper, from low-grade sulfide ores.
Which of the following describes a correct chemical or environmental advantage of bioleaching over traditional pyrometallurgical smelting?
It relies on high-temperature anaerobic fermentation, which significantly reduces the time required to extract metals compared to smelting.
It biochemically oxidizes insoluble metal sulfides to soluble sulfates in aqueous solution, avoiding the direct emission of sulfur dioxide gas.
It yields high-purity elemental metal directly from the bacterial culture, avoiding any subsequent electrolysis or displacement reactions.
It completely eliminates the production of acidic wastewater, as the bacterial metabolic byproducts are highly alkaline.
81 exam-style questions on OCR GCSE Chemistry Improving processes and products. Each one has a worked solution and a mark scheme showing where the marks go.