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Descrição
FlashCards por Natalia Cliff, atualizado more than 1 year ago
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Criado por Natalia Cliff
mais de 7 anos atrás
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| Questão | Responda |
| What are ores? | Ores are rocks that contain enough metal to make extraction economically viable. The economics of extraction may change over time |
| What do you do with Ores? | Ores are mined and may be concentrated before the metal is extracted and purified |
| What form do you find metal in in the crust? | Unreactive metals like Gold can be found as pure metals. Most metals, however, are found in compounds that require chemical reactions to extract the metals |
| How do you extract unreactive metals? | Metals less reactive than carbon can be extracted from their oxides by reduction with carbon |
| What do you do with iron oxide? | Iron oxide is reduced in a blast furnace to make iron |
| What do you do with metals more reactive than carbon? | They are extracted by electrolysis of molten compounds. The large amount of energy required for this makes these metals expensive (e.g. aluminium) |
| How is copper extracted? | Copper is extracted from copper-rich ores by heating the ores in a furnace (smelting). It's then purified by electrolysis |
| What are the issues with this method of extraction? | -Requires a lot of energy -Copper-rich ore supply is limited -Traditional mining and extraction have major environmental impact |
| What are alternative methods? (just list them) | -Phytomining -Bioleaching -Displacement with scrap iron -Electrolysis of copper salts |
| What happens in the process of phytomining? | -plants are grown over low-grade copper ores -Their roots absorb the metal -Plants are burned leaving behind ash with metal compounds in it |
| What happens in the process of bioleaching? | -Bacteria feed on low-grade copper ore -They produce a leachate solution that contains copper compounds |
| What are the other methods? | -Displace copper using scrap metal -Electrolysis of solutions of copper salts |
| What metals (2 specifically you need to know) can you not extract by reduction with carbon? | Aluminium and titanium cannot be extracted from their oxides by reduction with carbon. |
| Why is extraction of aluminium and titanium expensive? | -There are many stages -Large amounts of energy are required |
| Why should we recycle metals? | -Extracting them uses limited resources (aka, we will run out) -Extraction is expensive as it requires a lot of energy -Extraction damages the environment |
| How much of Iron from the blast furnace is iron? | 96% of iron from the blast furnace is iron. These impurities make it very brittle and so it has limited uses |
| What happens to iron from the blast furnace? | -Some of it is used as cast iron due to its strength in compression -Most of it is converted into Steels |
| What is steel? | Steel are alloys as they are mixtures of iron and carbon. Some steels contain other metals. These alloys can be designed to have specific properties |
| What kinds of steel are there? What are their properties? | -Stainless steel is resistant to corrosion -Low-carbon steel is easily shaped -High-carbon steel is hard |
| Why do we use alloys? | Most metals used everyday are alloys because pure copper, gold, iron and aluminium are too soft for many uses. They are mixed with similar metals to make them harder for everyday use |
| Where are transition metals (on the periodic table)? | The central block of the periodic table |
| What are the properties of transition metals? | -Good conductors of heat and electricity -Can be bent or hammered into place (malleable) |
| What are transition metals used for? | -Structural materials -Things that need to allow heat or electricity to pass through them easily |
| What are the properties of copper? | -Good conductor of electricity and heat -Can be bent, but hard enough for pipes or tanks -Doesn't react with water |
| What do copper's properties mean that it is used for? | -Electrical wiring -Plumbing |
| Why are aluminium and titanium useful? | -resistant to corrosion -low density |
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