ALUMINUM CELL HEARTH ROASTING METHOD Russian patent published in 2007 - IPC C25C3/06 

FIELD: metallurgy of aluminum, possibly installation of aluminum cells, namely roasting hearth of aluminum cell.

SUBSTANCE: method comprises steps of heating carbon lining of hearth with use of outer heat source for several stages; providing accelerated temperature elevation at initial stage of roasting; then sharply decreasing temperature elevation rate for intermediate stage al least by 3,5 - 7.0 times and smoothly increasing temperature elevation rate at least by 2 - 4 times for final stage of roasting process. Then hearth is subjected to soaking at temperature no less than 850°C at least for six hours. At initial stage of process at temperature less than 300°C heating is performed at rate 70 - 80°C/h; at intermediate stage in temperature range 300 - 570°C - at rate 7.5 - 8.5°C/h; at final stage in temperature range 570 - 850°C - at rate 15 - 18°C/h. Method provides lowered temperature gradient in inter-block joints of cell and uniform heating of hearth along height.

EFFECT: enhanced resistance of hearth to sodium action due to small changes of density and porosity along height of inter-block joints.

2 cl, 5 dwg