Abstract—The production of glass, ceramic materials and many non-ferrous metals (Zn, Cu, Pb, etc.), ferrous metals (pig iron) and others is connected with the use of a considerable number of initial solid raw materials. Before carrying out the basic technological processes (oxidized roasting, melting, agglomeration, baking) it is necessary to mix and homogenize the raw materials that have different chemical and phase content, granulometry and humidity.For this purpose zinc sulfide concentrates differing in origin are studied for their more complete characteristics using chemical, X-ray diffraction analyses, DTA and TGA as well as Mössbauer spectroscopy. The phases established in most concentrates are:
β-ZnS, mZnS.nFeS, FeS2, CuFeS2
, PbS, SiO2 (α-quartz).
With the help of the developed by us a Web-based information system for a continued period of time different mix proportions from zinc concentrates are calculated and used in practice (roasting in fluidized bed reactor), which have to conform to the technological requirements of the zinc hydrometallurgical technological scheme.Keywords—fluidized bed reactor, roasting, Web-based information system, zincconcentrates.
ERY often in zinc production by the hydrometallurgical method 6-10 initial zinc concentrates (of different origin) are used [1-3], as well as some semi-finished products. In most plants the content of 18 components and the humidity of the concentrates and the mix obtained from them are monitored. Some of them (Zn, S) are controlled by setting their minimum value necessary for the stable operation of the fluid bed reactor [4-10] and maintaining the necessary temperature (900-950 С). For the other components contained in the zinc concentrates (Fe, SiO2, Ga, In, Tl, Ge, As, Sb, etc.)a maximum content is determined, which depends on the used technological scheme . A large part of the technological processes are directed toward obtaining a ZnSO4 solution with a strictly determined content of impurities, which would allow for high purity cathode zinc (SHG) to be obtained by electrolysis at the best technical-economic indexes. In this regard the selection of a suitable proportion for the sulfide zinc concentrates and their homogenization before and during roasting are decisive. In this connection, the goal of this study is to characterize by different methods zinc concentrates processed in Bulgaria and with the expert Web-based information system tocalculate the optimal mixing proportions for roasting in fluidized bed furnaces from the studied concentrates.
II. RESULTS AND DISCUSSION
The work of the fluidized bed furnace (FBF) (Fig 1) as abasic energy and technological link in the process of
hydrometallurgical zinc production significantly influences the indexes of the process of production. The indexes of roasting depend on the technological regime, the FBF construction and to a great degree on the characteristics of the processed raw materials [12-20].In order to be able to control roasting in FBF a more
complete information is necessary about the influence of theconcentrates and the products from their oxidation roasting on the indexes of the roasting process. The place of the oxidation roasting process in FBF in the technological scheme for zinc production is presented in Fig 2. It shows where the developed Web-based information system for zinc mix calculation is used. It is crucial for the optimal implementation of the
oxidation process in FBF, the obtaining of a suitable in itscontent zinc calcine and all following processes – leaching,purification, electrolysis. The chemical composition of the studied concentrates is shown in table I. The origin of the studied concentrates is from: 1- Bulgaria; 2 – Peru; 3, 4- Serbia; 5, 6 – Macedonia; 7 – Bosnia&Herzegovina; 8 – Greece; 9 – Turkey. The process of zinc calcine leaching depends heavily on its phase composition. To a great degree it is determined by the initial phase and chemical composition of the concentrates, the roasting regime and the work of FBF. In this connection, a study of zinc concentrates in relation to their phase composition was performed by X-ray diffraction analysis. The obtained general results are presented in table II. The place of the developed software in the discussed scheme is in the process selection of raw materials and their suitable mixing. The goals in this specific case are:
• Obtaining of a zinc calcine with a suitable chemical
• To have the processes of ferrite formation and silicate formation take place at the lowest possible degree
• Content of Zn and S in the calcine not less than 50 % for Zn and 31 % for S
• Limiting the content of Pb, Fe, SiO2, Ge, Sb, As, Cl, CaO, F below the maximum admissible values. These values can be adjusted when necessary or when the technological scheme for calcine processing ischanged.
فریاد زدم در تاریخ 1390/05/22 فریاد پیمان علی اصغری