Agricultural Helps Extract Iron from Ore
Brazilian mines use corn and mandioca to separate sand from slurry.
John Otte
Published: Jul 13, 2011
Likely every American farmer has seen the displays or pictures of the huge number of food products processors make from corn and soybeans.
Most American farmers also recognize that Brazil grows huge volumes of numerous agricultural crops. Soybeans, sugar cane and coffee are readily recognized Brazilian ag products. Brazil also grows cotton, corn, sorghum, rice, citrus and all kinds of vegetables and forest products.
Mandioca, also known as manioc and cassava, is another sizable crop. It's a starch crop, used much like potatoes. It's the plant used to produce tapioca for pudding. Some Asian countries use Mandioca to produce ethanol.
"The iron mining industry uses huge amounts of mandioca and corn," said Genielzio Pereira. Fewer Americans know Brazil is a huge iron producer
Getting iron ore from the mines to where it is processed or exported is a challenge much like moving grain from farms to processors and exporters.
Samarco Mineração S. A. is expanding and building its third iron ore pipeline. The 240 mile pipeline will link Samarco's Germano mine in Mariana, Minas Gerais, Brazil to the industrial complex and port at Ubú, Brazil. It will have a nominal capacity of 20 million tons per year.
Separating the finely ground iron slurry
Oversimplified, Samarco finely grinds iron ore, then mixes it with water. Huge pumps push the iron-ore slurry through the pipelines across the mountains to the processing plant at the port.
I was told that the mining companies learned that the slurry flows easier if lubricated and that they have used both rice and mandioca to lubricate it.
"That's not quite correct," explained mining engineer Genielzio Pereira. "The iron mining industry uses huge amounts of mandioca and corn, but not to lubricate pipelines. Finely ground iron ore, ground corn or ground mandioca and a few other ingredients are mixed together in a basin. The iron settles to the bottom of the basin. Sand and other impurities adhere to corn or mandioca and are floated off before the ore goes into the pipeline."
At the port, the slurry is dewatered, then the finely ground iron is processed into pellets. Pellets are easier to unload and the destination. Plus pellets are ready to go into the furnace.
"The process goes on 24 hours a day, seven days a week, 365 days a year," says Pereira.
The third pipeline is due for completion by early 2014. Samarco is a privately held Brazilian mining company, owned by BHP Billiton and Vale. It produces 22.25 million tons of iron ore pellets annually. It is already the second largest exporter on the seaborne iron ore pellet market in the world.
Editors note. Otte is traveling in Brazil to study Brazilian agriculture and culture.
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