RESOUR CE PA CK Iron Mining and Processing in South · PDF fileIron Mining and Processing in...
Transcript of RESOUR CE PA CK Iron Mining and Processing in South · PDF fileIron Mining and Processing in...
Iron Mining and Processing in South Africa
R E S O U R C E P A C K
Iron Mining and Processing in South Africa
Source: Kumba Iron Ore, www.kumba.co.za
UNIVERS I TY OF CAPE TOWNIDYUNIVES I TH I YASEKAPA • UNIVERS I TE I T VAN KAAPSTAD
Road construction / concrete
manufacture
Crushing
Open pit mining is used to excavate iron ore that is closeto the surface. The topsoil is removed and the ore isloosened by drilling and blasting. Haulage trucks movethe ore to stockpiles. From there a conveyor belt systemtransports the ore to the crushers at the processing plant.
Blending anddispatch
Blast furnace
Washing andscreening
Surface mining
Steelmanufacturing
Separation andclassification
Pig iron Slag
Iron Ore (65% Fe)
The ore undergoes aseries of crushing stepsto reduce the particlesize.
Iron ore is separated intothe different grades usingcyclones and drumseparators.
Coke (carbon) is reduced:2C + O2 2COCO reacts with iron ore to form iron:3CO + Fe2O3 2Fe + 3CO2Flux (limestone) is added to removeimpurities from the molten iron to formslag:CaCO3 CaO + CO2CaO + SiO2 CaSiO3 (slag)Molten slag floats on top of the molteniron.
Coke (C)
Limestone (CaCO3)
Hot Air
The blast furnace produces pig ironthat is sent to steel manufacturers.
The blast furnaceFeed of ore,
fluxingagents and
coke
Removalof slag
Tapping ofmolten pig iron
Collection ofwaste gases
Hot blastfrom Cowperstoves
carbon dioxide forms
carbon monoxideforms
iron formsColumn of ore
coke andfluxing agents(e.g. limestone)
Road construction / concrete
manufacture
Blending anddispatch
Washing andscreening
Surface mining
Steelmanufacturing
Phosphate Mining and Processing in South Africa
R E S O U R C E P A C K
Phosphate Mining and Processing in South Africa
Source: Roux et al. (1989). Phosphates in South Africa. J.S.Afr.Inst.Min.Metall. 89(5):129-139.
UNIVERS I TY OF CAPE TOWNIDYUNIVES I TH I YASEKAPA • UNIVERS I TE I T VAN KAAPSTAD
Open-pit mining(Foskor)
Drilling andblasting
Ore from PalaboraMining Company
(PMC)Primary crusher
Milling
Secondary andtertiary crushers
PhosphateFlotation
Tailings totailings dam
Filtration ofconcentrate
Dispatch to fertilizercompany or
processing plant
Add sulfuric acid to make super-phosphate (mixture of calciumphosphate and calcium sulfate)
Drying
Add phosphoric acid to maketriple-super-phosphate
Ore from PMC undergoes copper flotation to removecopper and magnetic separation to remove magnetite(iron) ore prior to phosphate flotation.
2Ca5(PO4)3F + 7H2SO4 3Ca(H2PO4)2 + 7CaSO4 + 2HF Ca5(PO4)3F + 7H3PO4 + 5H2O 5Ca(H2PO4)2 • H2O + HF
Super-phosphates and triple-super-phosphates are used as fertilizers
Drilling andblasting
Secondary andtertiary crushers
PhosphateFlotation
Drying
The phosphate mining process at Foskor receivesphosphate rock from two sources: The Foskor open-pitmine and the Palabora Mining Company
Gold Mining and Processing in South Africa
R E S O U R C E P A C K
Gold Mining and Processing in South Africa
UNIVERS I TY OF CAPE TOWNIDYUNIVES I TH I YASEKAPA • UNIVERS I TE I T VAN KAAPSTAD
Refining
Recovery:smelting
Comminution:crushing &
milling
South African gold mines are deep level minesreaching depths of over three kilometres. Miners gounderground in shaft cages and then walk or taketrains to the work face.
The oreundergoes aseries of crushingand milling stepsto reduce its sizefor furtherprocessing.
Gold is leached from the slurry by meansof dilute cyanide solution. Gold has ahigh affinity for cyanide solution. Thefollowing reaction occurs:
Ganguerock goesto thetailingsdam
Unwanted rock (gangue) isfiltered out and zinc dust isadded to precipitate thegold. Zinc displaces gold ina redox reaction. Impuritiessuch as silver, platinum,copper, lead and zinc alsoprecipitate out.
Carbon is used to adsorb goldfrom the solution. This is calledthe ‘carbon-in-pulp’ process andinvolves three phases:- Adsorption, where dissolved
gold is loaded onto aeratedcarbon
- Elution, where gold is removedfrom carbon by an alkalinecyanide solution
- Electrowinning, where gold isremoved & deposited onsteel cathodes
The gold is smelted in an electric furnace to producegold bars of 99 % purity.
Filtration& zinc
precipitation
Carbon-in-pulp& electro-winning
Flux is added and the gold is melted in a furnace toseparate the gold from the impurities. The flux willoxidise the impurities, which will float on top of themolten gold and can be removed. Gold of 99,99%purity is produced.
4Au + 8NaCN + O2 + 2H2O 4NaAu(CN)2 + 4NaOH
Ore is hoisted from the lowestunderground level of the mine in skipsand then transported to the surface byrail hoppers or conveyor belts.
Leaching:cyanidation
process
Undergroundmining
Leaching:cyanidation
process
Undergroundmining
Recovery:smelting
Extraction:removing goldfrom solution
Source: Chamber of Mines, www.bullion.org.za
Zn + 2NaAu(CN)2 2Au + Zn(CN)2 + 2NaCN
Coal Mining and Processing in South Africa
R E S O U R C E P A C K
Coal Mining and Processing in South Africa
Bord-and-pillar method(65% recovery)
Rib-pillar method(90% recovery)
Longwall mining(90% recovery)
Source: Anglo Coal video 2008; Powering South Africa the Anglo Coal way.
Primary crushing takes place whilethe coal is still underground.Conveyor belts then transport thecoal to the secondary and tertiarycrushers at the processing plant.
The coal arrives at the coalwashing plant by means of a seriesof conveyor belts.
The coal is separated into differentsizes, called grades.
The coalis dried,ready fortransport.
UNIVERS I TY OF CAPE TOWNIDYUNIVES I TH I YASEKAPA • UNIVERS I TE I T VAN KAAPSTAD
Surfacemining
Undergroundmining
Crushing
Washing
Separation andclassification
Drying anddispatch
Local market(75%)
Export market(25%)
Householduse(2%)
Electricitygeneration
(53%)
Metallurgicalindustries
(12%)
Petrochemicalindustries
(33%)
Opencast mining is used to excavateshallow-lying coal seams. These seams aredrilled and blasted prior to excavation.Shovels load the coal onto haul trucks, whichtake it to the tipping area. Conveyor beltstransport the coal to the processing plant.
Surfacemining
Undergroundmining
Washing
Drying anddispatch
Householduse(2%)
Electricitygeneration
(53%)
Metallurgicalindustries
(12%)
Petrochemicalindustries
(33%)