Potassium, calcium, sodium, magnesium, aluminum, zinc, iron, tin, lead, copper, mercury, silver, platinum and gold.
It can be roughly divided into three sections.
Metals and Al before 1 are very active and are melted by electrolytic salts or oxides.
For example, sodium is electrolytically melted sodium chloride.
Magnesium is electrolytic molten magnesium chloride.
Aluminum is electrolytically molten Al2O3.
2. The middle section is generally thermal reduction. When heating, use a suitable reducing agent, such as H2, carbon, cobalt or more active metal aluminum (aluminothermic reaction) for smelting.
For example, H2, carbon and cobalt reduce CuO to obtain Cu by heating, and reduce Fe2O3 to obtain Fe, etc.
Smelting iron, chromium, manganese and other metals by aluminothermic reaction at high temperature.
3. The latter inert metal can be decomposed by direct heating oxide to obtain simple metal.
For example, HgO is decomposed into Hg and O2 by heating, which is a classic experiment in which lavoisier discovered the existence of O2 in the air.
First, electrolysis.
The sequence of metal activities in metal smelting is as follows:
2Al2O3 = cryolite, electrolysis = 4Al+3O2↑ =
The generated O2 reacts with the anode carbon rod to generate CO and CO2, so the anode carbon rod should be replenished continuously, and cryolite (Na3AlF6) is used as the flux. 〕
Second, the thermal reduction method
(1) C (COke, charcoal) and co are used as reducing agents. Such as 3CO+Fe2O3 = high temperature = 2Fe+3CO2.
(China is the first country to smelt zinc in the world, which was recorded by Song Yingxing in the book Tiangong Kaiwu in the Ming Dynasty).
(2) Melting refractory metals with thermite
2Al + Fe2O3 == Al2O3 + 2Fe
Third, the heating method
This inert metal can be smelted by heating its oxide or calcining its sulfide. For example:
2HgO = heating = 2Hg+O2↑ =
The Song of Autumn Pu by Li Bai in the Tang Dynasty: The fire shines on the heavens and the earth, and the red star is in chaos. Hao Lang, on a moonlit night, the song is moving in cold Sichuan. Qiupu: In the west of Chizhou City, Anhui Province, silver and copper were produced at that time. Haolang refers to smelting workers.
Fourthly, physical extraction.
It exists in nature and has a high density. It can be obtained by repeated elutriation to remove impurities such as ore particles and sediments. Liu Yuxi's "Langtaosha": Rizhao Chengzhou River is foggy, and gold diggers are all over the river. Behind the beautiful jewels is sand full of waves. (Wei: Where the water turns)
Verb (abbreviation of verb) Shui Ye
That is, the metallurgical process of extracting and separating metals from raw materials through chemical reactions (such as replacement, redox, neutralization, hydrolysis, etc.). ) in solution.
Such as copper smelting: Fe+CuSO4 == FeSO4+Cu.