铝土矿提取氧化铝的两大工艺流程

铝土矿提取氧化铝的两大工艺流程英文回答：
There are two major process flows for extracting alumina from bauxite, which is known as the Bayer process and the Hall-Heroult process.
The Bayer process is the most commonly used method for extracting alumina from bauxite. It involves several steps, including digestion, clarification, precipitation, and calcination. In the digestion step, crushed bauxite ore is mixed with a hot solution of sodium hydroxide, which dissolves the alumina content of the ore. The resulting mixture, called bauxite slurry, is then pumped into large tanks called digesters, where it is heated and stirred for several hours. During this process, impurities in the ore settle to the bottom, and the clear liquid containing dissolved alumina is separated from the solids.
After digestion, the bauxite slurry undergoes
clarification to remove any remaining impurities. This is done by adding a flocculant, which causes the impurities to clump together and settle at the bottom of the tanks. The clear liquid, known as clarified liquor, is then further processed.
In the precipitation step, the clarified liquor is cooled and seeded with alumina trihydrate crystals. This causes the dissolved alumina to crystallize out of the liquid. The resulting mixture of crystals and liquid,
called alumina hydrate, is then separated through a series of filters. The alumina hydrate is washed to remove any remaining impurities and is then dried.
The final step in the Bayer process is calcination, where the dried alumina hydrate is heated to a high temperature to remove the chemically-bound water. This results in the production of pure alumina, which can be used for various applications, including the production of aluminum.
The Hall-Heroult process, on the other hand, is used to
extract aluminum metal from alumina. It involves the electrolysis of alumina dissolved in molten cryolite. The process takes place in a large cell called an electrolytic cell. The cell consists of a carbon-lined steel pot, which acts as the cathode, and a carbon anode. A high electrical current is passed through the cell, causing the alumina to break down into aluminum metal and oxygen. The aluminum metal collects at the cathode and is periodically removed, while the oxygen is released as a gas.
中文回答：
铝土矿提取氧化铝的两大工艺流程分别是贝氏法和霍尔-埃罗特法。

贝氏法是提取铝土矿中氧化铝最常用的方法。

它包括消化、澄清、沉淀和焙烧等几个步骤。

在消化步骤中，将粉碎的铝土矿矿石与热的氢氧化钠溶液混合，使矿石中的氧化铝溶解。

得到的混合物称为铝土浆，然后被泵入称为消化釜的大型槽中，在其中加热搅拌数小时。

在这个过程中，矿石中的杂质沉淀到底部，含有溶解氧化铝的清澈液体与固体分离。

消化后，铝土浆经过澄清以去除任何剩余的杂质。

这是通过添
加絮凝剂来实现的，絮凝剂使杂质凝结并沉淀到槽底。

然后进一步
处理得到的清澈液体，称为澄清液。

在沉淀步骤中，澄清液被冷却并加入氢氧化铝三水合物晶体。

这导致溶解的氧化铝结晶出来。

晶体和液体的混合物称为氢氧化铝，然后通过一系列过滤器进行分离。

氢氧化铝经过洗涤去除任何剩余
的杂质，然后被干燥。

贝氏法的最后一步是焙烧，将干燥的氢氧化铝加热到高温，以
去除化学结合的水。

这样就得到纯氧化铝，可用于各种应用，包括
铝的生产。

另一方面，霍尔-埃罗特法用于从氧化铝中提取铝金属。

它涉及
将溶解在熔融冰晶石中的氧化铝进行电解。

该过程发生在一个称为
电解槽的大型电池中。

电解槽由内衬碳的钢罐和碳阳极组成。

通过
电池通入高电流，使氧化铝分解为铝金属和氧气。

铝金属在阴极处
集聚并定期取出，而氧气则释放为气体。