Alumina yield
Alumina Yield in the Bayer Process; Past, Present and Prospects Edited by
TMS (The Minerals, Metals & Materials Society), 2007
ALUMINA YIELD IN THE BAYER PROCESS
PAST, PRESENT AND PROSPECTS
Roelof Den Hond1, Iwan Hiralal2, Ab Rijkeboer3
Alcor Technology, Clinckenburgh 10, 2343 JH Oegstgeest, The Netherlands
2
Hiracon, Prinses Irenelaan 2, 2273 DD Voorburg, The Netherlands
3
Rinalco, Helmlaan 16, 2244 AZ Wassenaar, The Netherlands
1
Keywords: hydrate, alumina, yield, liquor productivity, precipitation, fines destruction, digestion, sweetening, low temperature, high temperature, extraction, recovery, mud-to-money, M2M-Technology
During the past decades a large number of alumina plants were successful in economically increasing the productivity of the
Bayer liquor loop. Over a period of 25 years the benchmark precipitation yield has increased from 70 g/l to 90+ g/l, whilst producing sandy alumina. However with the theoretical maximum precipitation yield at 160 g/l there is still a wide gap to be closed.
This paper provides an overview of past developments, the present status and the prospects, resulting from increased process knowledge and emerging technologies. It is envisaged that benchmark precipitation yield will soon cross the 100 g/l level.
INTRODUCTION
One of the key objectives of alumina production is to enrich the caustic solution in digestion with a maximum of alumina and to subsequently drive out a maximum of alumina from the solution in precipitation. In other words maximize alumina production per liter of circulated liquor, i.e. maximize liquor productivity or alumina yield. Increasing yield brings advantages in reduced capital cost per annual ton production capacity for digestion, precipitation, decantation, HID, evaporation and power house.
Also such unit operating costs as digestion steam, pumping power, labor, maintenance, overheads and other fixed costs decrease as yield increases.
Over the last 25 years the
TMS (The Minerals, Metals & Materials Society), 2007
ALUMINA YIELD IN THE BAYER PROCESS
PAST, PRESENT AND PROSPECTS
Roelof Den Hond1, Iwan Hiralal2, Ab Rijkeboer3
Alcor Technology, Clinckenburgh 10, 2343 JH Oegstgeest, The Netherlands
2
Hiracon, Prinses Irenelaan 2, 2273 DD Voorburg, The Netherlands
3
Rinalco, Helmlaan 16, 2244 AZ Wassenaar, The Netherlands
1
Keywords: hydrate, alumina, yield, liquor productivity, precipitation, fines destruction, digestion, sweetening, low temperature, high temperature, extraction, recovery, mud-to-money, M2M-Technology
During the past decades a large number of alumina plants were successful in economically increasing the productivity of the
Bayer liquor loop. Over a period of 25 years the benchmark precipitation yield has increased from 70 g/l to 90+ g/l, whilst producing sandy alumina. However with the theoretical maximum precipitation yield at 160 g/l there is still a wide gap to be closed.
This paper provides an overview of past developments, the present status and the prospects, resulting from increased process knowledge and emerging technologies. It is envisaged that benchmark precipitation yield will soon cross the 100 g/l level.
INTRODUCTION
One of the key objectives of alumina production is to enrich the caustic solution in digestion with a maximum of alumina and to subsequently drive out a maximum of alumina from the solution in precipitation. In other words maximize alumina production per liter of circulated liquor, i.e. maximize liquor productivity or alumina yield. Increasing yield brings advantages in reduced capital cost per annual ton production capacity for digestion, precipitation, decantation, HID, evaporation and power house.
Also such unit operating costs as digestion steam, pumping power, labor, maintenance, overheads and other fixed costs decrease as yield increases.
Over the last 25 years the
References: , h Metals (1986), 125-130. United States Patent Number 5,690,700, November, 1997.