Metals and Non-metals PDF

K state. For example, gold, silver, platinum and copper are found in the free state. Copper and silver are also found in the combined state as Na their sulphide or oxide ores. The metals at the top of the activit...

K state. For example, gold, silver, platinum and copper are found in the free state. Copper and silver are also found in the combined state as Na their sulphide or oxide ores. The metals at the top of the activity series Electrolysis Ca (K, Na, Ca, Mg and Al) are so reactive that they are never found in nature as free elements. The metals in the middle of the activity series Mg (Zn, Fe, Pb, etc.) are moderately reactive. They are found in the earth’s Al crust mainly as oxides, sulphides or carbonates. You will find that the ores of many metals are oxides. This is because oxygen is a very Zn reactive element and is very abundant on the earth. Fe Thus on the basis of reactivity, we can group the metals into the Reduction using following three categories (Fig. 3.9) – (i) Metals of low reactivity; (ii) Metals Pb carbon of medium reactivity; (iii) Metals of high reactivity. Different techniques Cu are to be used for obtaining the metals falling in each category. Several steps are involved in the extraction of pure metal from Ag ores. A summary of these steps is given in Fig.3.10. Each step is Found in native explained in detail in the following sections. Au state Figure 3.9 Activity series and related metallurgy Figure 3.10 Steps involved in the extraction of metals from ores 3.4.2 Enrichment of Ores Ores mined from the earth are usually contaminated with large amounts of impurities such as soil, sand, etc., called gangue. The impurities must be removed from the ore prior to the extraction of the metal. The processes 50 Science 2024-25