Bioleaching is an alternative biological method used to extract metals, such as copper, from low-grade ores. Which of the following is a major disadvantage of using bioleaching compared to traditional pyrometallurgical smelting?
It requires a high-energy electrical input to keep the bacterial cultures continuously heated at temperatures exceeding 300∘C300^\circ\text{C}300∘C.
It produces highly acidic leachates containing toxic metal ions that can contaminate local water systems if not carefully managed.
It is unable to process low-grade ores, making it economically viable only for high-grade concentrated mineral veins.
It releases large volumes of sulfur dioxide gas directly into the atmosphere during the biological digestion phase.
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.