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Partial PbS can cross-link with other lead compounds
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Partial PbS can cross-link with other lead compounds: PbS + 2PbO = 3Pb + SO 2 (15) PbS + PbSO 4 = 2Pb + 2SO 2 (16) To the reaction unincorporated PbS iron and copper sulfides with stein forms a phase. 161 Non-mineral rocks and to be added fluxes slag phase organize. A lot component lead melting slags bases FeO – ZnO – CaO – SiO 2 system organize does. This sum of oxides 90 from % will be more. One distinguishing feature of lead slag is that it contains 5-25 % of ZnO. If 20 in the slag % zinc oxide, the properties of slag almost do not change. Slag fluidization temperature is 1050 - 1150 0 C, viscosity is 0.5 - 1.0 Pa*s. If the concentration of silicon dioxide in the slag exceeds 30%, the viscosity increases, while an increase in the amount of FeO, on the contrary, decreases it. Liquid products of the process are divided into layers due to the density difference. The greater the density difference, the faster and more complete the separation. The density of slag depends on the density of its constituents, g/cm 3 : 2.7 SiO 2 ; 5.0 FeO; 3.3 CaO; 2.8 Al 2 O 3 . Slag with optimal composition should have the following properties: melting temperature 1100 - 1150 o C; viscosity at 1200 o C – 0.5 Pa*s; density 3.5 - 3.8 g/cm 3 . Slag with the following content has such properties, %: 20-30 SiO 2 , 30-40 FeO; 10-18 CaO; up to 25 ZnO. Other products of the process are stein and speiz. Approximate composition of copper-lead stein, %: 7-40 Cu; 16-45 Fe; 20-25 C; 8-17 Pb. Speiz is a combination of metals with arsenic and antimony. Its approximate composition, %: 2-15 Pb; 2-34 Cu; 20-50 Fe; 18-30 As; 1-6 Sat; 0.001-0.01 Au; 0.015 – 0.20 Ag. Speiz and matte are harmful products of the process. Precious metals are wasted with them. It is necessary to try to reduce their formation as much as possible. Fuel consumption in mine melting is 10-15% of the original mine. The melting process lasts 4-6 hours. The product obtained from smelting lead agglomerate in a blast furnace is crude lead, its composition is as follows: 93 to 98% metallic lead. Additives, %: Cu – 1.0-5.0; Sb - 0.5-2.0; As - 0.2-2.0; Sn - 0.1-0.2; Bi - 0.05-0.4; Te - 0.005-0.1; as well as Ag 1-5 kg / t, Au 1-50 g / t. Download 1.46 Mb. Do'stlaringiz bilan baham: |
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