Introduction “The practice of minerals processing is as old as human civilisation. Minerals and products derived from minerals have formed our development cultures from the flints of the Stone Age man to the uranium ores of Atomic Age”. The ambition with this handbook, “Basics in Mineral Processing Equipment”, is not to give a full coverage of the subject above. The intention is to give technicians involved in mineral operations practical and useful information about the process equipment used, their systems and operational environment. The technical data given are basic, but will increase the understanding of the individual machines, their functions and performances.
Basic Definitions rock and ore as they represent It is important to know the definitions of mineral, rock a different product values and partly different process systems Mineral
Rock
Ore
Na+ Ca2+ Si4+ O2CO22- Fe2+ OHHeat
Pressure
3
2
O i S
o C a C
3
O 2
e F
“Natural components of
l a r e n i M
l a r e n i M
l a r e n i M
Heat
Pr essure
k c o R
k c o R
k c o R Heat Defor mat ion
e r O
“Compounds of minerals”
chemical element s”
k c o R Pressure Chemical activity
e r O
e r O
“Rocks containing minerals or metals which can be recovered with profit”
Artificial minerals “Man made” minerals are not minerals by definitions. But from processing point of view they are similar to virgin minerals and are treated accordingly (mainly in recycling processes) processes)..
Slag
Concrete
BASICS BA SICS IN IN MI MINERA NERAL L PROCESSING PROCESSING
Mill scale
Glass & Ceramics
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Minerals by Value Minerals
Industr ial Miner als Abrasives Corundum Quartz Diamond a.o.
Ceramics Quartz Kaolin Feldspar a.o.
Glass Quartz Feldspar Calcite Dolomite a.o.
Fertilisers Phosphate Potash Calcite Dolomite a.o.
Plastic Calcite Kaolin Talc Wollastonite Mica a.o.
Fillers and Pigment Barite Bentonite Calcite Dolomite Feldspar Talc a.o.
Refractories Wollastonite Calcite Dolomite Corundum a.o.
Refractories Wollastonite Calcite Dolomite Corundum a.o.
Miner al Fuels
Rock
Coals Oil shale (Oil sand)
Aggrega ggregate, te, Sand & Gravel Gravel Concrete ballast Asphalt ballast Rock fill Industrial sand a.o.
Ores Non-ferrous Non -ferrous
Ferrous Fer rous Alloy
Base Metals Meta ls Copper Lead Zinc a.o.
Alloyin lloying g Meta M etals ls Chromium Vanadium Molybdenum Tungsten a.o.
Light Metals Aluminium Magnesium Titanium Precious Meta Metals ls Gold Silver Platinum a.o. Rare Metals Uranium Radium Beryllium a.o.
Introduction The Process Frame of Minerals The goal in mineral processing is to produce maximum value from a given raw material. This goal can be a crushed product with certain size and shape or maximum recovery of metals out of a complex ore. The technologies to achieve these goals are classical, complementary and well defined. Below they are presented in the Process Frame of Minerals, classified according to their interrelations in product size and process environment (dry or wet).
Size
8
1m
100 mm
10 mm
1 mm
100 micr on
10 micron
1 micron
Drilling (and blasting) is the technology of achieving primary fragmentation of “in situ” minerals. This is the starting point for most mineral processes with the exception of natural minerals in the form of sand and gravel. Crushing and screening Crushing scr eening is the first fir st controlled c ontrolled size reduct reduction ion stage in the process. This is the main process in aggregate production and a preparation process for further size reduction. Grinding is the stage of size reduction (wet or dry) where the liberation size for individual minerals can be reached. By further size reduction filler (mineral powder) is produced. Slurry proce process ssing ing inclu includes des the technologies technologies for f or we wett processing of min mineral eral fractions. Pyro proce process ssing ing inclu includes des the technologies technologies for f or up upgrading grading of the mineral mineral fractions fr actions by drying, calcining or sintering. Mate rials handling Materials handling inclu includes des the techn t echnologies ologies for f or movin moving g the t he process flow fl ow (dry) (dry) forwa for ward rd by loadin loading, g, tran tr ansport sportation, ation, storage and and feedin feeding. g. Compaction of minerals includes the technologies for moving and densifying minerals by vibration, impaction and pressure, mainly used in construction applications.
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Introduction n o i t c u d o r t n I
Mineral Processing and Hardness All deposits of minerals, rock or ores have different hardness depending on the chemical composition and the geological environment. Mohs numbers are a simple classification: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
Talc Gypsum Calcit e Fluorite Apat it e Feldspar Quart z Topaz Coru run ndum Diamond
Graphite, Sulphur, Mica, Gold Dolomite Magnesite Magnetite Granite, Pyrite Basalt Beryl
Crushed by a finger nail Scratched by a finger nail Scratched by an iron nail Easily scratched by a knife Scratched by a knife Hardly scratched by a knife Scratches glass Scratched by quartz Scratched by a diamond Cannot be scratched
In 1813 an Austrian geologist, Mr. Mohs, classified minerals according to their individual hardness.
In operation we naturally need more information about our feed material. See information on work index an and d abrasion index, section 3 page 2.
Size and Hardness All operations have different process environments due to mineral hardness and size range. It is important to know in which “range” we are operating as this will affect many process parameters, (wear rate, uptime, operation costs etc.). Size and hardness together give interesting information. Hardness Mohs 10
ROCK
CONSTRUCTION
METALLIC MINERALS
MATERIALS
9 8
BALLAST
7 6 AGGREGATES
SAND
5 4 MICRO FILLER SAND
3 2
INDUSTRIAL MINERALS Size
1:4
8
1m
100 mm
10 mm
1 COARSE FILLER FIN FINE E FILLER 1 mm
100 micron
10 micron
1 micron
BASICS BA SICS IN MI MINERA NERAL L PROCESSING PROCESSING
Introduction The Stress Forces of Rock Mechanics Beside size and hardness, the classical stress forces of rock mechanics are the fundamentals in most of what we do in mineral processing. They guide us in equipment design, in systems layout, in wear protection etc. They are always around and they always have to be considered.
Tensile
Compression
Impaction
Shearing
Attrition
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