tecnología

Origins of metals
  • From minerals which are found in rocks
  • Ore is a type of rock that contains minerals that can be economically extracted(the useful part)
  • Gangue is the commercially worthless material that surrounds,or is closely mixed with the ore
  • Most ores are a chemical compound of the metal with other elements,such as oxygen(oxide),sulfur(sulfide),carbon and oxygen(carbonate)

  • Metallurgy studies the physical and chemical behaviour of metals and alloys and the technology of metals
  • Siderugy is ferrous metallurgy or black metallurgy
Mining
It is the extraction of valuable minerals
    Mining processes
  • Prospecting(exploration)of a territory
  • Analysis of the profit potential
  • Extraction
  • Reclamation(restoring)of land
    Mining techniques(excavation types)
    • Surface mining
    • Open-pit mining
    • Quarrying(open-pit mining of sand,stone and clay)
    • Strip mining(used to mine coal and lignite-brown coal-)
    • Mountaintop removal(used to mine coal)
    • Landfill mining and reclamation(proccess of previously been landfilled-solid wastes-)
    • Underground mining(digging tunnels or shafts)
    • Drift mining
    • Slope mining
    • Shaft mining
    • Shrinkage stope,long wall,room and pillar,retreat,hard rock,bore hole,drift and fill,long hole slope,sub level cavin,block caving...
    Mineral processing
  • Comminution and beneficiation(breaking down the ore)
    • Crushing(compression and impact forces)and grinding(attrition)
  • Sizing(separation according to their size by screening-static or shake or vibrate-)
  • Concentration will depend on the relative properties of ore/gangue
    • Gravity concentration-centrifugal,magnetic and buoyant forces-
    • Froth flotation(foam of hydrophobic and hydrophilic materials)/flotación en espuma
    • Classification
    • Magnetic separation
    • Electrostatic separation
    • Leaching(hydrometallurgy-converts metals into soluble salts in aqueous media-)
      Pyrometallurgy(high temperature processes)
    • Roasting/Tostación(the ore-sulfide minerals-is treated with very hot air and converted to an oxide,and sulfur dioxide is released)
    • Calcining/Calcinación(the ore-carbonate and hydrated minerals-is processed in the absence or limited supply or air,and carbon dioxide or water is released)
    • Smelting/Fundición(it is more than melting the metal. The ores have to undergo a chemical reaction-needs to be reduced-to free the metal and at least one product is a molten phase)
    • Refining/Refinado(Removal of impurities)
      Electrometallurgy(a current is passed through a liquid solution containing the metal that is deposited onto the cathode)for non-ferrous metals

Properties of metals
    Density(g/cm3)
  • Metals have a density greater than water
    They are heavy materials
    Sodium0.97
    Magnesium1.74
    Beryllium1.85
    Aluminium2.70
    Titanium4.51
    Gallium5.91
    Vanadium6.0
    Zinc7.14
    Chromium7.15
    Tin7.26
    Manganese7.3
    Iron7.87
    Cadmium8.69
    Copper8.96
    Cobalt8.90
    Nickel8.908
    Silver10.5
    Lead11.3
    Mercury13.53
    Tantalum16.4
    Uranium19.1
    Tungsten19.25
    Gold19.3
    Plutonium19.7
    Platinium21.5
    Iridium22.5
    Osmium22.59
    Melting point(°C)
  • At room(ambient)temperature,they are in solid state,
    with the exception of mercury
    Mercury−38.8290
    Galinstan(Ga+In+Sn)-19
    Gallium29.7646
    Tin231.93
    Lead327.46
    Zinc419.53
    Silver961.78
    Gold1064.18
    Copper1084.62
    Iron1538
    Aluminium3422
    Electrical conductivity(107S/m)
  • Metals are good conductors of electricity
    graphene10.0
    Silver6.3
    Copper5.96
    Gold4.10
    Aluminium3.5
    Tungsten1.79
    Zinc1.69
    Nickel1.43
    Iron1.00
    Platinum0.943
    Tin0.917
    Lead0.455
    Titanium0.238
    Thermal conductivity(approximately tracks electrical conductivity due to freely moving valence electrons)
  • Metals are good conductors of heat
    Acoustic conductivity
  • Metals are good conductors of sound
    Corrosion
  • Metals need to be protected from corrosion especially from sea water and humidity
    Elasticity
  • Not very good compare to plastics or wood
    Plasticity
  • Most metals show more plasticity when they are heated
  • At room temperature:copper,lead,gold,silver show good plasticity
    Malleable
  • the ability to deform(to form a thin sheet)under compressive stress
  • Gold,platinum,aluminium,lead
    Ductile
  • the ability to deform(drawn into wires)under tensile stress
  • Gold,copper
    Hardness
    Opaque
    Shiny
  • characteristic shine
    Colour
  • Almost all elemental metals have a gray or silver colour(caesium and gold is yellow,osmium is buish and copper is reddish)
    Fusible
  • Able to be fused or melted
    Ecological properties
  • Most metals are recyclable
    Toxic
  • Heavy metals,lead,mercury

Classification of metals
  • Ferrous(ferric)metals
    • Iron
    • Steel
    • Cast Iron
  • Non-Ferrous(non-ferric)metals
    • Heavy metals:metals with densities above 5 g/cm3
      • Copper
      • Tin
      • Zinc
      • Lead
      • Mercury
      • Nickel
      • Chromium
      • Manganese
      • Gold,Silver,Platinum
    • Light metals:metals with densities between 2 and 5 g/cm3
      • Aluminium(Aluminum-AmE-)
      • Titanium
    • Ultra-Light metals:metals with densities below 2 g/cm3
      • Magnesium
      • Beryllium

Iron
  • It is by mass the most common element on Earth(outer and inner core)
  • It is the fourth most common element inthe Earth
  • It is reactive to oxygen and water(hydrated iron oxides-rust-)
    • Process of obtaining iron
      • The iron ore is extrated from open-pit or subterranean mines
      • then crushing and grinding
      • then it is separated using magnet systems
      • then smelting in a blast furnace
      Siderurgy
      • study of the processes through which ferrous materials are obtained
      The most common iron ores:
      • Magnetite Fe3O4
      • Hematite Fe2O3
      • Goethite FeO(OH)
      • Limonite FeO(OH)·(H2O)
      • Siderite FeCO3
Blast furnace
  • It is a vertical shaft(circular tower)furnace used for smelting iron(and other metals:lead,copper...)
  • Iron ore(hematite and magnetite),coke(type of coal)and fluxes(limestone and dolomite)are loaded into the top of the furnace
  • A hot air blast is blown into the bottom of the furnace
  • The molten iron-pig iron-come out through a tap hole in the lower part of the furnace
  • The slag which is lighter than pig iron come out through another tap hole
  • The combustion gases emerge from the top of the furnace
  • The heat from the combustion gases go to the Cowper stove-heat exchanger-to heat the air blown into the furnace
  • Pig iron has 4-5%carbon with small amounts of impurities like sulfur,magnesium,phosphorus and manganese
  • Carbon make iron brittle and hard
Iron in ancient times
  • Objects made of meteoric iron(contain nickel)
  • The Hittites began to smelt iron between 1500 and 1200 BCE
  • Charcoal was required as fuel
  • The iron was then hammered to remove the slag,yielding wrought iron
  • Mechanical bellows for introducing greater amounts of air into the furnace-14th century-
  • The depletion of forests led to produce coke-early 18th century-
  • Preheating the combustion air-early 19th century-
Pure Iron
  • It is an alloy of iron and carbon(between 0.008%adn 0.03%)
  • It has a good magnetic properties
Steel
  • It is obtained by smelting pig iron and scrap in furnaces(converters)
  • It is obtained by Direct-Reduced Iron(DRI)and Electric Arc Furnaces(EAF)
  • It is an alloy of iron and carbon(less than 1.76%and more than 0.03%)
Processes for making steel
  • From 1850s and1860s until 1990s:The Bessemer and Siemens-Martin process(open hearth furnace)
  • Today:Basic Oxygen Furnace(BOF)-LD converter-and Electric arc furnace(EAF)
  • Feed materials:pig-iron,scrap steel or direct reduced iron(DRI)
Direct reduced iron(DRI)
  • Iron ore is reduced at 800 to 1050°C either by reducig gas(H2and CO)or coal
  • It is the feedstock for EAF
Cast iron
  • It is an alloy of iron and carbon(between 1.76%and 6.67%)
  • It is hard,brittle
  • Types of cast iron:grey cast iron,white cast iron,malleable cast iron and ductile cast iron

Copper
Copper mean metal of Cyprus
The most common copper ores:
  • Chalcopyrite CuFeS2
  • Chalcocite Cu2S
  • Cuprite,azurite,malachite ...
Properties of copper
  • It is malleable and ductile
  • It has a very high thermal and electrical conductivity
  • It is one of the pure(noble and native)metals found in nature in large amounts(gold,silver and platinum ...)
  • It is resistant to corrosion and oxidation in moist air
  • It has a reddish colour and when it oxidizes a greenish colour
  • It has brazing,soldering and welding properties
  • It is biostatic(bacteria will not grow on it)and antimicrobial material
Alloys of copper
  • Brass is an alloy of copper and zinc
  • Bronze is an alloy of copper and tin
  • It is one of the constituents of silver and gold alloys
  • Cupronickel is used for coins
Aluminium
Aluminium is the third most common element in the earthThe aluminium ore is bauxite
Bauxite(named for Les Baux in Provence in France)is a mixture of Al(OH)3,AlO(OH)and other minerals
Aluminium form alloys with copper,magnesium,silicon,zinc,tin,titanium,scandiumProperties of aluminium
  • It is easy to recycle
  • It is light(low density)
  • It is resistant to corrosion(to weather conditions)
  • It has a good thermal and electrical conductivity(it is a good conductor of heat and electricity)
  • It is non-toxic
  • It has high plasticity(it is easy to shape)
  • it is ductile and malleable
  • Aluminium powder is highly flammable(it is used in pyrotechnics)
Magnesium
Magnesium(named for Magnesia in Greece)
The most common magnesium ores:
  • Magnesite,dolimite,carnallite,epsomite and olivine
Properties of magnesium
  • It is a very lightweight metal
  • React very strongly with oxygen and water
  • Magnesium powder is highly flammable(it is used in pyrotechnics)
  • Very soft and malleable
  • The chief use is to make aluminium-magnesium alloys
Titanium
  • The most common titanium ores:rutile and ilmenite
  • It is a lightweight metal
  • It can be alloyed with iron,aluminium,vanadium and molybdenum...
  • It is a corrosion resistance material
  • It is as strong as some steels,but less dense and more than twice as strong as aluminium alloy
  • It is biocompatible(it is non-toxic and is not rejected by the body)
Tin
  • It is very resistant to corrosion
  • It is very ductile and malleable
  • It is obtained form cassiterite SnO2
  • It is used in many alloys
    • Bronze an alloy of tin and copper
    • Solder and alloy of tin and lead
  • It is used in tin plating of steel(corrosion-resistant tin cans)
Zinc
  • It is highly resistant to corrosion
  • It is ductile and malleable
  • The most common zinc ore is sphalerite and hemimorphite
  • It is used in brass,which is an alloy of copper and zinc
  • It is used in zinc plating of iron(galvanizing)
Lead
  • It is very toxic and poisonous and it is a neurotoxin
  • It is soft and malleable
  • It is obtaining from galena PbS
  • It has a high density
  • During the 20th century,Lead was used in paints,batteries,petrol(gasoline),solders,water systems
Dictionary of metals
Metalurgy(metal making)=Metalurgia
Siderurgy(Iron and Steel making)=Siderurgia
Coal=Carbón
Charcoal=Carbón vegetal
Peat=Turba
Lignite coal=Lignito
Sub-Bituminous coal/Bituminous coal=Hulla
Anthracite coal=Antracita
Coke=Coque
Blast Furnace(from Latin oven)=Alto Horno
Cupola or cupola furnace=Cubilote
Electric Arc Furnace(EAF)=Horno de arco eléctrico
Basic Oxygen Furnace(BOF)=Horno básico de oxígeno
Pig Iron=Arrabio
Wrought iron=Hierro forjado
Iron=Hierro
Steel(Alloy of iron and carbon-0.03%-1.76%C-)=Acero
Cast iron(Alloy of iron and carbon-1.76%-6.67%C-)=Fundición-hierro fundido-
White Cast Iron(as a Carbide)=Fundición blanca
Grey Cast Iron(as a graphite)=fundición gris
Brass(Alloy of copper and zinc)=Latón
Bronze(Alloy of copper and tin)=bronce
Copper=Cobre
Duraluminium-duralumin,duraluminum,dural-(Alloy of Aluminium,copper,magnesium,manganese)=Duralumino
Tin=Estaño
Lead=Plomo
Gold=Oro
Ceramic kiln=Horno para cerámica
Boiler=Caldera
Heater=Calentador
Carbon=Carbono
Silver=Plata
Ore=mena
Tin plate(Thin steel coated with a layer of tin)=Hojalata
Ingot=Lingote
Blacksmith=Herrero
Goldsmith=Orfebre-Artesano del Oro-
Silversmith=Orfebre-Artesano de la plata-
Alloy=Aleación
Solder=Estaño para soldar