Bevel-helical gear unit B3 r unit dimensions threest age gear unit sizes t B3-CH18A

Flender/Flender Gear Units/Bevel-helical gear unit B3

overed. 1 2. Working steps The most important sub-steps of the process are leaching of the zinc concentrate, FeSO, cry- stallisation out of the solution containing zinc sulphate, oxidation of Fe ( to Fe (Ill), precipita- tion of iron to purify the lye, and the pyrometallurgical processing of the lye residue The studies carried out within the framework of the research project are - Leaching in technical appliances with various zinc concentrates of different origins - Iron oxidation in various appliances with the goal of determining the possible oxygen - Iron precipitation to purify the resulting zinc sulphate solution - Pyrometallurgical processing of the leaching residue containing elementary sulphur - Development of computer program to coordinate the results of the various studies - Preliminary investigations concerning the direct pyrometallurgical processing of zinc conversion and the consumption of oxidising agents sulphide concentrates 3. Results Developmentworkon the direct leaching of zincsulphide concentrates hasshown that, dueto multi-step leaching, the process becomes too complicated to reach the zinc concentration desired for zinc electrolysis. In addition, separate leaching/oxidation and solid/liquid separa- tion in both stages causes high equipment outlay and thus has an unfavourable .ffect on the investment costs. The crystallisation process, which is carried out by cooling the lye containing FeSO,/ZnSO,, leads to difficulties due to the fact that the co-precipitation of the zinc cannot be kept to low level. Thus, the quantity of zinc in the cycle increases and burdens it. The heat consumption of the crystallisation process also proved to be too high. These and other foreseeable problems regardin the drying of the leaching residue containing element- ary sulphur made continuation of tEe originally planned project unadvisable. The development of cyclone technology for the pyrometallur ical processing of concentrates and i