Graduate qualifying work Theme: Selection and calculating of zinc sulfate production technology

Fluidized bed furnace

Let us consider the firing process in a fluidized bed furnace in more detail using chemistry, thermodynamics, and kinetics.

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  Let us consider the firing process in a fluidized bed furnace in more detail using chemistry, thermodynamics, and kinetics.
  
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  The effect of firing conditions on the process performance
  
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  In the firing process, temperature plays a significant role. Temperature can vary from 850 to 980 0C. At low temperatures, the firing process is slow and incomplete; at high temperatures, the material is melted and firing is not of high quality. To control the temperature, water coolers are used (cooling), receiving steam, and a certain temperature is maintained by the loading speed. So that the concentrate does not grow larger during firing, it is necessary to maintain a temperature of not more than 970 0C. A moderate content of soluble sulfate sulfur is achieved at a temperature of 950-970 0C. With increasing temperature, at the same time, there is a need to resolve the issue of removal and utilization of excess heat from the BL zone. At low temperatures, firing of sulphide materials promotes the formation of sulphates both because the dissociation pressure at these temperatures is lower and because the pressure of PSO3 in the furnace gases is higher.
  

Technological Part

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  Selective dissolution of zinc concentrate depends on the regime.
  
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  The composition of the concentrate of a single-stage selective dissolution solution is 97% Zn, 98% Cd, 68% Cu,12% Fe, 75-80% as sulfur element, 5-10% sulfate.
  
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  98,5% Zn of the solution in two stage selective melting.
  
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  Horizontal autoclave with 2-4 chambers in selective melting: diameter 3,2 m, length 15.2 m, geometric volume 130 m3 , working volume 100m3 , consisting of anti-acid brick, steal … and asbestos layer. In each selection is used a trubine torch mixer.
  
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  Chemical cleaning of zinc sulfate.
  
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  The chemical cleaning process is carried out by cementation of zinc solution.