Material handling blending systems

Aluminum reduction plants Materials handling Buckets and belt Conveyor or pneumatic conveyor Anode and cathode electrode preparation Cathode (haldng) Anode (grinding and blending) Particulates (dust) Hydrocarbon emissions from binder Particulates (dust) Exhaust systems and baghouse Exhaust systems and mechanical collectors... 

Polyurethanes based on MDI have the greatest flexibility in the choice of curatives and blends of curatives that can be used to obtained the desired properties. In cast elastomers, the hygroscopic nature of the curatives must be taken into account and proper handling and storage used otherwise, there may be a very high reject rate. Catalysts are also more readily used with the MDI materials. Organic acids such as adipic or oleic acids work better with TDI materials than MDI systems. 

The handling of incoming concentrates, their storage, blending with flux materials and feeding to the sinter plant requires the use of mobile equipment, feed bins and conveyor systems. Electric power used is around 5 kWh/t of materials handled or 12 kWh/t of product lead. Fuels used for mobile equipment represents 75 MJ/t of material handled or 180 MJ/t of product lead. 

This standard covers the requirements for molded or fabricated parts. Material identity-control systems intended to provide tracability of material used for polymeric parts through the handling, molding or fabrication, and shipping operations are described. Guidelines are also provided for the acceptable blending or simple compounding operations that may affect risk of fire, electrical shock, or personal injury. 

Once a uniform blend has been obtained, it is essential that the particles in the blend cease movement to allow the system to exist in a state of static equilibrium without segregation occurring. From a practical point of view, this is not possible as subsequent material transfer during the compression or filling operations involves material How. Therefore, care must be exercised to ensure that the impact each subsequent handling step has on the equilibrium achieved for the blend at the conclusion of the blending operation is minimized. The mechanisms by which powders can segregate, as well as means to control it, will be discussed later in this chapter. 

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