Atomic Number ........................................ 30
Atomic Weight ........................................ 65.38
Density (g/cm^3) ..................................... 7.13
Density (lb/in^3) .................................... 0.257
Melting Point (C) .................................... 419.5050
Melting Point (F) .................................... 787.1090
Boiling Point (C) .................................... 906
Boiling Point (F) .................................... 1663
Specific Heat (cal/g-C) .............................. 0.0915
Specific Heat (J/kg-K) ............................... 383
Heat of Fusion (cal/g) ............................... 24.09
Heat of Fusion (Btu/lb) .............................. 43.36
Coefficient of linear thermal expansion (uin/in/C) ... 39.7
Coefficient of linear thermal expansion (uin/in/F) ... 22.0
Thermal conductivity (cal/cm^2/cm/sec/C) ............. 0.27
Electrical resistivity (uohm-cm) ..................... 5.916

Property Estimates

Young's Modulus (polycrystalline zinc) ............... 15,200,000 psi
Young's Modulus (ZA-8 zinc) .......................... 12,400,000 psi
UTS (AC-41A zinc) .................................... 48,000 psi
TYS (ZA-8 zinc) ...................................... 29,000 psi
Elongation % in 2 inches (AC-41A zinc) ............... 7%
Bulk Modulus (polycrystalline zinc) .................. 10,100,000 psi
Shear Modulus (polycrystalline zinc) ................. 6,080,000 psi
Poisson's Ratio (polycrystalline zinc) ............... 0.249

Formula               DH0f       DG0f       S0         C0p
                      kJ/mol     kJ/mol     J/K mol    J/K mol
Zn(c)                   0.0        0.0        41.63     25.40
Zn2+(g)              2782.78       --          --        --
ZnO(c)               -348.28    -318.30       43.64     40.25
ZnS(c, wurtzite)     -192.63       --          --        --
ZnS(c, sphalerite)   -205.98    -201.29       57.7      46.0

----------------------------------------------------------------------------
Notes: These molar values apply to pure substances at 25oC and exactly
100000 Pa (1.0 bar or 100 kPa) pressure. One standard atmosphere pressure is
slightly higher, 101325 Pa, but the change in tabulated values between these
two pressures is neglegible for all solids and liquids and minor even for
gases. Physical states are indicated by c (crystalline solid), l (liquid),
and g (gas). Different crystalline structures are designated by common or
mineralogical names. Common names for selected compounds are also given.
Values are taken from U.S.N.B.S. tables of molar thermodynamic properties
(J. Phys. Chem. Ref. Data 11, Suppl. 2 (1982)) unless in italics.
----------------------------------------------------------------------------

Formula          DH0f       DG0f       S0       C0p
                 kJ/mol     kJ/mol     J/K mol  J/K mol
Zn2+           -153.89    -147.06  -112.1      46.
Zn(CN)42-       342.3      446.9    226.         --
Zn(NH3)42+     -533.5     -301.9    301.         --
Zn(OH)42-         --      -858.52     --         --

----------------------------------------------------------------------------
Notes: These standard molar values apply to (infinitely) dilute aqueous
solutes at 25oC and exactly 100 kPa (1.0 bar) pressure. One standard
atmosphere pressure is slightly higher, 101.325 kPa, but the change in
tabulated values between these two pressures is neglegible for all solids,
liquids, and ions. It is minor even for gases. Values are taken from
U.S.N.B.S. tables of molar thermodynamic properties (J. Phys. Chem. Ref.
Data 11, Suppl. 2 (1982)) unless in italics.
----------------------------------------------------------------------------

Compound   Ksp            
Zn(OH)2    4.13 x 10-17
ZnS        2.93 x 10-25

----------------------------------------------------------------------------
Notes: These molar values apply in (infinitely) dilute aqueous solutions at
25øC. The values are calculated from U.S.N.B.S. tables of molar
thermodynamic properties unless in italics. Solubility products are the
equilibrium constants for the formation of solutions of the constituent ions
of a slightly soluble salt from the pure solid salt.
----------------------------------------------------------------------------

Ion            Constant     log Kstab

Zn(CN)42-      5.70 x 10+16   16.756
Zn(NH3)42+     3.60 x 10+8     8.557
Zn(OH)42-      3.97 x 10+15   15.599

----------------------------------------------------------------------------
Notes: These molar values apply in (infinitely) dilute aqueous solutions at
25oC. The values are calculated from U.S.N.B.S. tables of molar
thermodynamic properties unless in italics. Stability constants are the
equilibrium constants for the formation of the complex ion from its
constituent simpler ions.
----------------------------------------------------------------------------

Electrode Couple          E0, V     dE0/dT, mV/K
Zn2+ + 2e- --> Zn         -0.7621   +0.119

----------------------------------------------------------------------------
Notes: Values for 0.1 MPa and 25oC in aqueous 1.0 molar acid solution,
calculated from U.S.N.B.S. tables of molar thermodynamic properties unless
in italics. The potential values are given to the nearest 0.1 mV if known,
thermal coefficients to the nearest 0.001 mV/K if known. The thermal
coefficient is that of the isothermal cell in which one of the electrodes is
the standard hydrogen electrode. Ions are all aqueous. Elements and
compounds are pure substances, present in their usual state at 25oC, unless
otherwise indicated. The saturated calomel reference potential is the
experimental value for pure mercury in contact with an aqueous solution
saturated with both Hg2Cl2 and KCl.
----------------------------------------------------------------------------

"Zinc (Zn) was used in Rome and China more than 2000 years ago as a component of brass (zinc-copper alloy). Zinc metal was first smelted from zinc ore in India in about 1200 and is known to have been used in China soon after. Commercial production of zinc did not start in Europe until the middle of the 18th century and in the United States until 1860. In deposits mined today, zinc ore (rock containing economic content of zinc and/or other materials) usually occurs mixed with ores of lead, silver and commonly copper, and is extracted as a co-product of these metals."

"The main zinc mineral is sphalerite (Zn,FeS), which contains up to 67% zinc. Smithsonrte (ZnCO3, 52% zinc), willemite (Zn2SiO4, 59% zinc) and hemimorphite (Zn4Si2O7(OH)2.H2O, 54% zinc) may occur in the near-surface weathered or oxidised zone of an orebody."

"Deposits containing zinc form from hot (hydrothermal) fluids generated within the earth. These fluids may be trapped below the surface in cracks where sphalerite and other minerals may precipitate to make vein deposits. Where limestones occur, the fluids may fill cavities to form rich but patchy deposits. Some fluids may reach the ocean floor in areas of underwater volcanic activity to form 'volcanogenic' deposits. Other fluids may escape to the surface through cracks or faults into small shallow lakes or seas and, if conditions are right, lead-zinc-silver deposits may form."

They go on to provide further description of Zinc deposits in Australia:

"Weathering and erosion may expose these deposits at the surface. Such partially eroded deposits were relatively easily discovered, examples are the Broken Hill and Mt Isa deposits, found late last century and early this century. These deposits formed the basis of Australia's zinc mining industry."

"Exposed deposits are becoming harder to find in Australia and exploration companies are now looking beneath the surface for the deposits of the future. This is a more costly and difficult way to find orebodies but a series of successes have occurred since the late 1970s. Such discoveries include the Scuddles mine (140 metres below surface) and Admiral Bay (1.5 km below surface) in Western Australia, the Cannington deposit in north Queensland, the Hellyer mine in Tasmania (90 metres below surface) and the Wilga-Currawong mine in Victoria (50 metres below surface)."

"In 1883, Charles Rasp discovered the rich, large Broken Hill lead-zinc-silver deposit in New South Wales (NSW) which provided the basis for zinc mining as a major industry in Australia. Over 100 years later ore is still being mined at Broken Hill and it has been the largest producer of lead-zinc-silver in Australia."

"The rich lodes at Mt Isa were not discovered until 1923 and were developed despite the remote location and harsh environment. The nearby, rich Hilton deposit was discovered in the late 1940s but not developed until the mid-1980s. Mt Isa has been the second biggest zinc producer in Australia. Further north-west, in the Northern Territory, the huge McArthur River lead-zinc-silver deposit is now being developed. Other large deposits yet to be mined in the region are Century, Dugald River and Cannington."

"Zinc ore is also produced at Rosebery and Hellyer at Tasmania; Elura, Woodlawn and Cobar in NSW; Woodcutters in the NT; Cadjebut and Scuddles in WA, Wilga-Currawong in Victoria and Thalanga in Queensland. High-grade zinc silicate ore is mined intermittently from the small Beltana deposit in South Australia."

"Traditionally, Canada, the United States and Australia have led the world in terms of economic zinc resources. Australia now ranks first in the world because of the development of the largest lead-zinc deposit in the world at McArthur River, NT. This position is further supported by the large resources in the world-class deposits of Century, Cannington and Dugald River."

"In the early days of Broken Hill, zinc ore was rejected to the waste dumps because virtually none of the zinc could be extracted economically. Gravity and magnetic separation methods were unsuccessful. In 1901 a flotation process was devised at Broken Hill which achieved recovery of upwards of 60% of the zinc minerals from ore. After considerable experimentation, a selective flotation method that worked on a commercial scale was perfected in 1912. Improved versions of this flotation process, such as the Australian-developed Jameson flotation cell, are used worldwide today. The Jameson flotation cell is installed in many mines around Australia."

"Almost all of Australia's zinc mines are underground operations and are highly mechanised. Ore is drilled and blasted in large volumes, transferred to underground rock crushers by large loaders and trucks, and then hoisted to the surface in skips or driven directly to the surface by truck via a spiral access tunnel (decline). A continuous underground mining machine is being developed at Broken Hill in NSW to increase efficiency by replacing the drill and blast phase."

"At the surface, the ore is subjected to additional crushing and fine grinding. The flotation process is then used to separate the zinc and other valuable sulphide minerals from the waste rock particles (tailings) to form a concentrate."

"Ground ore, water and special chemicals are mixed and constantly agitated in banks of flotation cells. Air is blown through the mixture in each cell, and the fine zinc sulphide particles stick to the bubbles, which rise to form a froth on the surface of the flotation cell. The tailings sink and are removed from the bottom of the cell. The froth is skimmed off and the resulting zinc sulphide concentrate is dried. This process upgrades the ore, which may contain only 6% Zn, to a concentrate assaying at more than 50% Zn. Up to 90% of the zinc in the ore can be recovered."

"Electrolysis and smelting are the two processes used to produce zinc metal in Australia. The electrolytic process is used at the Risdon zinc refinery in Tasmania. In this process, zinc concentrate from various Australian mines is roasted to eliminate most of the sulphur as sulphur dioxide and make impure zinc oxide. The roasted concentrate is then leached with sulphuric acid to form zinc sulphate solution. A significant amount of zinc ferrite (ZnO.Fe203) is also produced and this is acid leached again to form zinc and iron sulphate solution. This solution is then treated with ammonia to remove most of the iron as an ammonium jarosite precipitate (insoluble solid compound). The zinc sulphate solution is purified by adding a small amount of zinc powder to precipitate and remove traces of copper, cadmium, cobalt and nickel from the solution. The solution is piped to electrolytic cells, where the zinc is electrochemically deposited on aluminium cathodes (electrodes). The zinc is removed from the cathodes, melted in a furnace and cast into slabs."

"The smelting process is used at Cockle Creek near Newcastle in NSW, to produce zinc (and lead) metal simultaneously in a blast furnace. Zinc and lead concentrates from various mines are blended and sintered (heated but not melted) to combine the fine particles into lumps and remove the sulphur as sulphur dioxide. The sintered product is mixed with coke and smelted in a blast furnace to produce zinc vapour (gas), which is condensed by cooling the hot blast furnace and gas with a spray of molten lead to form impure molten zinc metal (98.3% Zn). To remove the small amount of lead and cadmium impurities the liquid zinc is twice boiled to zinc vapour and recondensed to produce high purity zinc metal (up to 99.95% Zn)."

"At Port Pirie, zinc is recovered from the lead smelter slag (molten waste) which contains about 17% zinc. The molten slag is heated further to drive off zinc (and some lead) vapour, which is oxidised to form a zinc oxide fume which is then filtered out as dust in a 'bag filter'. This dust is ground and put through an electrolytic refining plant to produce high purity zinc."

"Primary refined zinc is produced at three plants - Risdon (Tasmania), Cockle Creek (NSW), and Port Pirie (SA). Production of secondary refined zinc occurs at Port Kembla (NSW). Zinc oxide and zinc dust is produced from scrap zinc at West Footscray in Melbourne (Victoria) and a minor amount in Brisbane (Queensland)."

"A large part of the world's zinc is used as protective galvanised coatings for iron and steel. In Australia, this use accounts for well over half of the domestic sales of zinc. The widespread use of zinc as a protective coating is mainly because of its resistance to normal weathering, and the protection given to steel by the preferential corrosion of zinc when the underlying iron or steel is exposed by scratches. This is an electrochemical reaction known as galvanic action. The construction and appliance manufacturing industries use large amounts of zinc, mainly as coatings on steel beams, sheet steel and vehicle panels in the automotive industry."

UNS     ASTM    SAE  Common   Al       Cu         Mg
------  ------  ---  -------  -------  ---------  -----------
Z33520  AG 40A  903  Zamak 3  3.5-4.3      <0.25  0.020-0.050
Z33523  AG 40B  ---  Zamak 7  3.5-4.3      <0.25  0.005-0.020
Z35531  AC 41A  925  Zamak 5  3.5-4.3  0.75-1.25  0.030-0.080
Z35541  AC 43A  ---  Zamak 2  3.5-4.3  2.50-3.00  0.020-0.050

Alloy Selection: Not as critical as with copper and aluminum alloys because zinc alloys are cast at relatively lower temperatures and do not rapidly attack ferrous metals.

Injection: Hydraulic or pneumatic actuated injection cylinders are common. Good practice is to use the lowest pressure that will produce an acceptable casting.

Dies: Although hot work tool steels are not generally required for casting zinc, where the die temperature is about 325-475F, hot work tool steels such as H11, H12, and H13 give the best life on long runs. Die hardnesses of 29-34 HRC (280-320 Bhn) are typical. When additional strength is needed, 440B SST cores and 7140 ejector pins are used. Die life is a function of die design, trained operators, and a machine and die maintenance program.

Die Temperature: Die temperatures typically range from 325-475F with thick-section castings run at the low end and thin-section castings run on the high end. Once established the die temperature should be maintained at +/-10F.

When dies are too cold: cold shuts, laminations, internal porosity, incomplete filling, and poor finish with excessive flow marks are expected.

When dies are too hot: shrinkage, heat sinks, excessive flash, spitting, poor ejection, soldering, and die erosion can take place.

Die Lubricants: Lubricant selection depends on operating temperatures and die shape. An optimum lubricant carbonizes at the operating temperature. A lubricant that carbonizes above the operating temperature will stain the casting. A lubricant that carbonizes below the operating temperature will be used up in the first shot. One lubricant application should last 5-6 shots.

Casting Temperature Control: Zinc metal temperatures range from 735-780F with the lower end used for thick-section castings and the higher end used for thin-section castings. When the optimum molten metal temperature is determined, it should be controlled to +/-10F.

Alloy Composition Control: Zinc die-cast alloys are typically more sensitive to variations in composition than aluminum.

Melt agitation can result in air entrapment.

Overheating results in the loss of aluminum through oxidation and an increase in iron.

Soldering: The adhering of metal to the die occurs in areas of the die that have become pitted because of repeated impingement of a high-velocity spray on the die surface, combined with the overheating that this impingement creates. Soldering results in surface defects such as pimples and torn skin on the casting.

Shrinks: Shrinks occur at metal concentrations such as ribs or uncored bosses. Shrinks can be reduced by increased casting pressure or the use of cores in thick sections.

Porosity: Porosity may take the form of a layer of finely dispersed microporosity beneath the dense skin of the casting.

Shrinkage Voids

Cracks

Misruns

Inclusions