Lead is chemical element IV of group of a periodic system. It represents metal of livid color. In the nature five of its stable isotopes and as much radioactive meet.
Instruction
1. Lead is the good absorber of gamma radiation, however he badly installs electrical equipment and heat. Oxidation level +2 (most probable) and also +4 is characteristic of lead.
2. There are about 80 minerals which contain lead. The most known of them — a galenite, it is called still lead gloss. The greatest value for the industry have cerussite and anglezit. Waters of the World Ocean of lead contain 0.03 mkg/l, in total about 41.1 million tons, in river waters — 0.2-8.7 mkg/l.
3. Lead is fusible metal, at the same time it is considered heavy non-ferrous metal. It is soft and plastic, it is possible to make the thinnest sheets of it easily. Copper increases his corrosive firmness, and at addition of antimony the hardness and acid resistance of lead in relation to sulfuric acid increases.
4. Lead is quite inert in the chemical relation, in dry air it is not oxidized, but in damp grows dull and becomes covered by an oxidic film. At reaction with oxygen a number of oxides is formed. Lead does not react from diluted with hydrochloric and sulfuric acids at the room temperature as on its surface almost insoluble films which interfere with further dissolution of metal are formed.
5. In relation to water solutions of ammonia and alkalis lead is steady, its best solvent is steady the diluted acetic or nitric acid. At the same time acetate and nitrate of lead is formed, also this metal is considerably soluble in ant, wine and lemon acids.
6. Lead reacts with halogens when heating, in its interaction with azotistovodorodny acid lead azide is formed, when heating with sulfur — sulfide. Hydrides are not characteristic of lead, however in some reactions it is possible to find lead tetrahydride — colourless gas which easily decays on lead and hydrogen.
7. The main source of receiving lead are sulphidic polymetallic ores. Take lead concentrates from them by method of selective flotation. As a rule, the lead concentrate contains 40-75% of lead, 5% of copper, from 5 to 10% of zinc and precious metals. About 90% of lead receive by methods of the agglomerating roasting of sulphidic concentrates, mine recovery melting and refinement of draft lead.
8. On volumes of consumption and production of non-ferrous metals lead takes the fourth place. Up to 45% there are for production of electrodes for accumulators, and about 20% - on production, cables, wires and coverings for them. Lead is actively used for creation of the equipment in chemical industry and also as screens for protection against x-ray or radioactive radiation.