Copper Production - Materials and Heat Balance in Metallurgical Processes - Lecture Notes, Study notes of Materials Physics

Download Copper Production - Materials and Heat Balance in Metallurgical Processes - Lecture Notes and more Study notes Materials Physics in PDF only on Docsity! Converting Key words: Copper production, converting, material balance It is important that the reader should consult any text book on non-ferrous metal extraction to familiarize with the process of converting. Detailed description about the converting process is not given here. The following description is given with a view to solve the problems on converting. In production of copper, converting is an important unit process. Matte, which is a mixture of copper and iron sulphide, is treated in Pierce-smith-Converter. The converter has the form of a horizontal cylindrical drum, and is usually lined with magnesite brick. In converting matte is converted to molten copper. It is done in two stages. In the stage-1 air is blown to oxidize all Fe of matte. During blowing of air silica is added to flux the FeO. The reaction is The oxidation of iron sulphide produces enough heat to maintain the temperature of the bath 1300 . After practically all iron is slagged-off more matte is added to the converter and the process is repeated until a sufficiently large amount of copper sulphide is obtained. This is called white metal. After removal of last slag, blowing is continued to produce molten blister copper. The reaction is The reaction of oxidation of copper sulphide is exothermic. In the converting process no heat supply from outside is needed. The basics of converting operation are illustrated by the following problem; Illustration with solution and discussion A copper converter is charged with 20 tons of matte and blown down to blister copper. Copper grade of the matte is 46%. The flux used carries 4%, FeS 16% and 80%. The slag carries 29% . Assume no loss of copper in slag. Also air is supplied at the rate of 90 . Calculate: (a) Total weight of flux and slag produced (b) The cubic meter of blsat for the entire blow (c) The blowing time for each of the following stages (d) Percent in the gases (e) Assuming all fluxes added at the start, after how many minutes blowing will the matte contain 60% copper (f) Heat generated in both the stages. No loss of copper in slag, Also it must be known that slag consists of FeO and only. Hence slag composition is 29% and 71% FeO. Let X kg is the weight of flux and Y kg is the weight of slag. From balance: 0.8X = 0.29Y (1) FeO balance: 0,102X + 5409 = 0.132Y (2) By solving equations 1 and 2 we get weight of flux = 3807 Kg and that of slag is 10503 Kg. Converting reaction for the entire blow: Slag formation stage : and (3) Blister formation stage: (4) From the amounts of and FeS oxidised, one can calculate the amount of oxygen and hence amount of air for both the stages. The amount of air 24325.3 . Time required for slagging stage = Time required for blister copper formation stage =