Increase in the stability of gravimetric classification system of precipitation at hydro alunorte

Abstract

After the installation of coarse seed filtration at lines 1, 2 and 3 at Hydro Alunorte, the precipitation productivity was increased, however the effect of higher concentration of solids in the circuit generated some operational problems. Small interruptions in the feed of the filters were responsible for significant production losses resulting from the overload of solids on the classification system caused by the addition of liquor to the chain. In order to improve circuit stability, the underflow streams from the secondary classifier were divided between the first cementator, where the control of supersaturation occurs, and second cementator, where it is fed excess seed. When the seed filter stops, its feed reduces and the flow to second cementator increases, eliminating the flow variation in the chain. Furthermore, statistical modeling was performed to regulate the concentration of solids in the feed of the thickeners, reducing the overload to it.