What is the price of zinc today?
Zinc metal is a base metal which is – among other things – used as a material to manufacture smartphones.
North American zinc price from 2016 to 2020 (in U.S. dollars per pound)*
| Characteristic | Price in U.S. dollars per pound |
| 2020* | 1.09 |
| 2019 | 1.24 |
| 2018 | 1.41 |
| 2017 | 1.39 |
What is the cost of zinc ingot per pound?
Has the price of zinc increased?
(28 June 2021) Zinc prices showed 50% growth year-over-year in May 2021, an increase to $2,965 per metric ton from $1,975 in May 2020. … The price is currently 11.5% above the 5-year moving average — a figure analysts were not expecting, since zinc demand is declining in the era of COVID-19.
Is zinc ingot a precious metal?
Base metals are any nonferrous (they contain no iron) metals that are neither precious metals nor noble metals. The most common base metals are copper, lead, nickel, tin, aluminum, and zinc. … Noble metals, some of which also are precious, are unlike base metals because they resist oxidation.
What is the cheapest metal to buy?
What is the cheapest metal zinc ignot to buy?
Iron, steel, aluminum, copper, zinc, lead, cadmium, manganese, and magnesium are some of the cheapest metals that can be found. Although aluminum is the most abundant metal on the planet, it is a bit costly to get it in its pure form.
Base metals are any nonferrous (they contain no iron) metals that are neither precious metals nor noble metals. The most common base metals are copper, lead, nickel, tin, aluminum, and zinc. Base metals are more common and more readily extracted than precious metals, which include gold, silver, platinum, and palladium. Noble metals, some of which also are precious, are unlike base metals because they resist oxidation. Some common examples of noble metals include silver, gold, osmium, iridium, and rhodium.
Characteristics
Pure base metals oxidize relatively easily. Except for copper, they all react with hydrochloric acid to form hydrogen gas. Base metals also are less expensive than their counterpart precious metals because they are so much more common.
Applications
Base metals are used in a wide variety of applications. Copper is commonly used in electrical wiring because of its high ductility and conductivity. Its high ductility means it easily can be stretched thin without losing strength. Copper also is good for wiring since it is the one base metal that resists oxidation and does not corrode as easily.
Lead has proven to be a reliable source for batteries, and nickel often is used to strengthen and harden metal alloys, including stainless steel. Base metals also are used frequently to coat other metals. For example, zinc is used to coat galvanized steel.
Trade
While base metals aren’t considered to be as valuable as their precious metal counterparts, they do still have value because of their practical uses. According to Investopedia, economists frequently use copper as an indicator for global economic forecasts because of its widespread use in construction. If there’s lower demand for copper, that means construction is down, which could be a sign of an economic downturn. If the demand for copper is up, the opposite would be true.
Aluminum is the third most abundant element in the earth’s crust (trailing only oxygen and silicon) and it does the highest volume of trading on the London Metal Exchange (LME). Extremely malleable, which means it can be pressed into sheets, aluminum has many uses, particularly in making containers for food or other products.
Metals traded on the LME are contracts for delivery 90 days forward.
The third most actively traded base metal on the LME is zinc, trailing only copper and aluminum. In addition to being used to coat galvanized steel, zinc is a common ingredient in coins, is frequently used in die-casting, and has many applications in construction, including pipes and roofing.
- Published in Uncategorized, Uncategorized, Uncategorized
What is Ingot Zamak
ZAMAK (or Zamac , formerly trademarked as MAZAK) is a family of alloys with a base metal of zinc and alloying elements of aluminium, magnesium, and copper.
Zamak alloys are part of the zinc aluminum alloy family; they are distinguished from the other ZA alloys because of their constant 4% aluminium composition.
The name zamak is an acronym of the German names for the metals of which the alloys are composed: Zink (zinc), Aluminium, Magnesium and Kupfer(copper). The New Jersey Zinc Company developed zamak alloys in 1929.
The most common zamak alloy is zamak 3. Besides that, zamak 2, zamak 5 and zamak 7 are also commercially used.These alloys are most commonly die cast. Zamak alloys (particularly #3 and #5) are frequently used in the spin castingindustry.
A large problem with early zinc die casting materials was zinc pest, owing to impurities in the alloys. Zamak avoided this by the use of 99.99% pure zinc metal, produced by New Jersey Zinc’s use of a refluxer as part of the smelting process.
Zamak can be electroplated, wet painted, and chromate conversion coated well.
Mazak
In the early 1930s Morris Ashby in Britain had licensed the New Jersey zamak alloy. The 99.99%-purity refluxer zinc was not available in Britain and so they acquired the right to manufacture the alloy using a locally available electrolytically refined zinc of 99.95% purity. This was given the name Mazak, partly to distinguish it from zamak and partly from the initials of Morris Ashby. In 1933, National Smelting licensed the refluxer patent with the intent of using it to produce 99.99% zinc in their plant at Avonmouth.
Zamak Standards
Zinc alloy chemical composition standards are defined per country by the standard listed below:
| Zinc alloy standards per country | ||
| Country | Zinc ingot | Zinc casting |
| Europe | EN1774 | EN12844 |
| US | ASTM B240 | ASTM B86 |
| Japan | JIS H2201 | JIS H5301 |
| Australia | AS 1881 – SAA H63 | AS 1881 – SAA H64 |
| China | GB 8738-88 | – |
| Canada | CSA HZ3 | CSA HZ11 |
| International | ISO 301 | – |
Zamak goes by many different names based on standard and/or country:
| Various names for zamak alloys | ||||||||||||
| Traditional name | Short composition name | Form | Common | ASTM† | Short European designation | JIS | China | UK BS 1004 | France NFA 55-010 | Germany DIN 1743-2 | UNS | Other |
| Zamak 2 or Kirksite |
ZnAl4Cu3 | Ingot | Alloy 2 | AC 43A | ZL0430 | – | ZX04 | – | Z-A4U3 | Z430 | Z35540 | ZL2, ZA-2, ZN-002 |
| Cast | ZP0430 | – | Z35541 | ZP2, ZA-2, ZN-002 | ||||||||
| Zamak 3 | ZnAl4 | Ingot | Alloy 3 | AG 40A | ZL0400 | Ingot type 2 | ZX01 | Alloy A | Z-A4 | Z400 | Z35521 | ZL3, ZA-3, ZN-003 |
| Cast | ZP0400 | ZDC2 | – | Z33520 | ZP3, ZA-3, ZN-003 | |||||||
| Zamak 4 | Ingot | Used in Asia only | ZA-4, ZN-004 | |||||||||
| Zamak 5 | ZnAl4Cu1 | Ingot | Alloy 5 | AC 41A | ZL0410 | Ingot type 1 | ZX03 | Alloy B | Z-A4UI | Z410 | Z35530 | ZL5, ZA-5, ZN-005 |
| Cast | ZP0410 | ZDC1 | – | Z35531 | ZP5, ZA-5, ZN-005 | |||||||
| Zamak 7 | ZnAl4Ni | Ingot | Alloy 7 | AG 40B | – | – | ZX02 | – | – | – | Z33522 | ZA-7, ZN-007 |
| Cast | – | Z33523 | ||||||||||
| †color of the cell is the color of the material designated by ASTM B908. | ||||||||||||
The Short European Designation code breaks down as follows (using ZL0430 as the example):
- Z is the material (Z=Zinc)
- P is the use (P=Pressure die casting (casting), L=Ingot)
- 04 is the percent aluminum (04= 4% aluminum)
- 3 is the percent copper (3= 3% copper)
Zamak 2
Zamak 2 has the same composition as zamak 3 with the addition of 3% copper in order to increase strength by 20%, which also increases the price. Zamak 2 has the greatest strength out of all the zamak alloys. Over time it retains its strength and hardness better than the other alloys; however, it becomes more brittle, shrinks, and is less elastic.
Zamak 2 is also known as Kirksite when gravity cast for use as a die. It was originally designed for low volume sheet metal dies. It later gained popularity for making short run injection molding dies. It is also less commonly used for non-sparking tools and mandrels for metal spinning.
Zamak 2 composition per standard |
||||||||||||
| Alloying elements | Impurities | |||||||||||
| Standard | Limit | Al | Cu | Mg | Pb | Cd | Sn | Fe | Ni | Si | In | Tl |
| ASTM B240 (Ingot) | min | 3.9 | 2.6 | 0.025 | – | – | – | – | – | – | – | – |
| max | 4.3 | 2.9 | 0.05 | 0.004 | 0.003 | 0.002 | 0.075 | – | – | – | – | |
| ASTM B86 (Cast) | min | 3.5 | 2.6 | 0.025 | – | – | – | – | – | – | – | – |
| max | 4.3 | 2.9 | 0.05 | 0.005 | 0.004 | 0.003 | 0.1 | – | – | – | – | |
| EN1774 (Ingot) | min | 3.8 | 2.7 | 0.035 | – | – | – | – | – | – | – | – |
| max | 4.2 | 3.3 | 0.06 | 0.003 | 0.003 | 0.001 | 0.02 | 0.001 | 0.02 | – | – | |
| EN12844 (Cast) | min | 3.7 | 2.7 | 0.025 | – | – | – | – | – | – | – | – |
| max | 4.3 | 3.3 | 0.06 | 0.005 | 0.005 | 0.002 | 0.05 | 0.02 | 0.03 | – | – | |
| GB8738-88 | min | 3.9 | 2.6 | 0.03 | – | – | – | – | – | – | – | – |
| max | 4.3 | 3.1 | 0.06 | 0.004 | 0.003 | 0.0015 | 0.035 | – | – | – | – | |
| Zamak 2 properties | ||
| Property | Metric value | Imperial value |
| Mechanical properties | ||
| Ultimate tensile strength | 397 MPa (331 MPa aged) | 58,000 psi |
| Yield strength (0.2% offset) | 361 MPa | 52,000 psi |
| Impact strength | 38 J (7 J aged) | 28 ft-lbf (5 ft-lbf aged) |
| Elongation at Fmax | 3% (2% aged) | |
| Elongation at fracture | 6% | |
| Shear strength | 317 MPa | 46,000 psi |
| Compressive yield strength | 641 MPa | 93,000 psi |
| Fatigue strength (reverse bending 5×108 cycles) | 59 MPa | 8,600 psi |
| Hardness | 130 Brinell (98 Brinell aged) | |
| Modulus of elasticity | 96 GPa | 14,000,000 psi |
| Physical properties | ||
| Solidification range (melting range) | 379—390 °C | 714—734 °F |
| Density | 6.8 kg/dm3 | 0.25 lb/in3 |
| Coefficient of thermal expansion | 27.8 μm/m-°C | 15.4 μin/in-°F |
| Thermal conductivity | 105 W/m-K | 729 BTU-in/hr-ft2-°F |
| Electrical resistivity | 6.85 μΩ-cm at 20 °C | 2.70 μΩ-in at 68 °F |
| Latent heat (heat of fusion) | 110 J/g | 4.7×10−5 BTU/lb |
| Specific heat capacity | 419 J/kg-°C | 0.100 BTU/lb-°F |
| Coefficient of friction | 0.08 | |
KS
The KS alloy was developed for spin casting decorative parts. It has the same composition as zamak 2, except with more magnesium in order to produce finer grains and reduce the orange peel effect.
| KS composition | ||||||||||||
| Alloying elements | Impurities | |||||||||||
| Standard | Limit | Al | Cu | Mg | Pb | Cd | Sn | Fe | Ni | Si | In | Tl |
| Nyrstar | min | 3.8 | 2.5 | 0.4 | – | – | – | – | – | – | – | – |
| max | 4.2 | 3.5 | 0.6 | 0.003 | 0.003 | 0.001 | 0.020 | – | – | – | – | |
| KS properties | ||
| Property | Metric value | Imperial value |
| Mechanical properties | ||
| Ultimate tensile strength | < 200 MPa | < 29,000 psi |
| Yield strength (0.2% offset) | < 200 MPa | < 29,000 psi |
| Elongation | < 2% | |
| Hardness | 150 Brinell max | |
| Physical properties | ||
| Solidification range (melting range) | 380—390 °C | 716—734 °F |
| Density | 6.6 g/cm3 | 0.25 lb/in3 |
| Coefficient of thermal expansion | 28.0 μm/m-°C | 15.4 μin/in-°F |
| Thermal conductivity | 105 W/m-K | 729 BTU-in/hr-ft2-°F |
| Electrical conductivity | 25% IACS | |
| Specific heat capacity | 419 J/kg-°C | 0.100 BTU/lb-°F |
| Coefficient of friction | 0.08 | |
Zamak 3
Zamak 3 is the de facto standard for the zamak series of zinc alloys; all other zinc alloys are compared to this. Zamak 3 has the base composition for the zamak alloys (96% zinc, 4% aluminum). It has excellent castability and long term dimensional stability. More than 70% of all North American zinc die castings are made from zamak 3.
| Zamak 3 composition per standard | ||||||||||||
| Alloying elements | Impurities | |||||||||||
| Standard | Limit | Al | Cu† | Mg | Pb | Cd | Sn | Fe | Ni | Si | In | Tl |
| ASTM B240 (Ingot) | min | 3.9 | – | 0.025 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.1 | 0.05 | 0.004 | 0.003 | 0.002 | 0.035 | – | – | – | – | |
| ASTM B86 (Cast) | min | 3.5 | – | 0.025 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.25 | 0.05 | 0.005 | 0.004 | 0.003 | 0.1 | – | – | – | – | |
| EN1774 (Ingot) | min | 3.8 | – | 0.035 | – | – | – | – | – | – | – | – |
| max | 4.2 | 0.03 | 0.06 | 0.003 | 0.003 | 0.001 | 0.02 | 0.001 | 0.02 | – | – | |
| EN12844 (Cast) | min | 3.7 | – | 0.025 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.1 | 0.06 | 0.005 | 0.005 | 0.002 | 0.05 | 0.02 | 0.03 | – | – | |
| JIS H2201 (Ingot) | min | 3.9 | – | 0.03 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.03 | 0.06 | 0.003 | 0.002 | 0.001 | 0.075 | – | – | – | – | |
| JIS H5301 (Cast) | min | 3.5 | – | 0.02 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.25 | 0.06 | 0.005 | 0.004 | 0.003 | 0.01 | – | – | – | – | |
| AS1881 | min | 3.9 | – | 0.04 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.03 | 0.06 | 0.003 | 0.003 | 0.001 | 0.05 | – | 0.001 | 0.0005 | 0.001 | |
| GB8738-88 | min | 3.9 | – | 0.03 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.1 | 0.06 | 0.004 | 0.003 | 0.0015 | 0.035 | – | – | – | – | |
| †Impurity | ||||||||||||
| Zamak 3 properties | ||
| Property | Metric value | Imperial value |
| Mechanical properties | ||
| Ultimate tensile strength | 268 MPa | 38,900 psi |
| Yield strength (0.2% offset) | 208 MPa | 30,200 psi |
| Impact strength | 46 J (56 J aged) | 34 ft-lbf (41 ft-lbf aged) |
| Elongation at Fmax | 3% | |
| Elongation at fracture | 6.3% (16% aged) | |
| Shear strength | 214 MPa | 31,000 psi |
| Compressive yield strength | 414 MPa | 60,000 psi |
| Fatigue strength (reverse bending 5×108 cycles) | 48 MPa | 7,000 psi |
| Hardness | 97 Brinell | |
| Modulus of elasticity | 96 GPa | 14,000,000 psi |
| Physical properties | ||
| Solidification range (melting range) | 381—387 °C | 718—729 °F |
| Density | 6.7 g/cm3 | 0.24 lb/in3 |
| Coefficient of thermal expansion | 27.4 μm/m-°C | 15.2 μin/in-°F |
| Thermal conductivity | 113 W/mK | 784 BTU-in/hr-ft2-°F |
| Electrical resistivity | 6.37 μΩ-cm at 20 °C | 2.51 μΩ-in at 68 °F |
| Latent heat (heat of fusion) | 110 J/g | 4.7×10−5 BTU/lb |
| Specific heat capacity | 419 J/kg-°C | 0.100 BTU/lb-°F |
| Coefficient of friction | 0.07 | |
Zamak 4
Zamak 4 was developed for the Asian markets to reduce the effects of die soldering while maintaining the ductility of zamak 3. This was achieved by using half the amount of copper from the zamak 5 composition.
| Zamak 4 composition per standard | ||||||||||||
| Alloying elements | Impurities | |||||||||||
| Standard | Limit | Al | Cu | Mg | Pb | Cd | Sn | Fe | Ni | Si | In | Tl |
| Ningbo Jinyi Alloy Material Co. | min | 3.9 | 0.3 | 0.03 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.5 | 0.06 | 0.003 | 0.002 | 0.002 | 0.075 | – | – | – | – | |
| Genesis Alloys Ltd. | min | 3.9 | 0.3 | 0.04 | – | – | – | – | – | – | – | – |
| max | 4.2 | 0.4 | 0.05 | 0.003 | 0.002 | 0.001 | 0.02 | 0.001 | 0.02 | 0.0005 | 0.001 | |
| Zamak 4 properties | ||
| Property | Metric value | Imperial value |
| Mechanical properties | ||
| Ultimate tensile strength | 317 MPa | 46,000 psi |
| Yield strength (0.2% offset) | 221—269 MPa | 32,000—39,000 psi |
| Impact strength | 61 J (7 J aged) | 45 ft-lbf (5 ft-lbf aged) |
| Elongation | 7% | |
| Shear strength | 214—262 MPa | 31,000—38,000 psi |
| Compressive yield strength | 414—600 MPa | 60,000—87,000 psi |
| Fatigue strength (rotary bending 5×108cycles) | 48—57 MPa | 7,000—8,300 psi |
| Hardness | 91 Brinell | |
| Physical properties | ||
| Solidification range (melting range) | 380—386 °C | 716—727 °F |
| Density | 6.6 g/cm3 | 0.24 lb/in3 |
| Coefficient of thermal expansion | 27.4 μm/m-°C | 15.2 μin/in-°F |
| Thermal conductivity | 108.9—113.0 W/m-K @ 100 °C | 755.6—784.0 BTU-in/hr-ft2-°F @ 212 °F |
| Electrical conductivity | 26-27% IACS | |
| Specific heat capacity | 418.7 J/kg-°C | 0.100 BTU/lb-°F |
Zamak 5
Zamak 5 has the same composition as zamak 3 with the addition of 1% copper in order to increase strength (by approximately 10%), hardness and corrosive resistance, but reduces ductility.It also has less dimensional accuracy. Zamak 5 is more commonly used in Europe.
| Zamak 5 composition per standard | |||||||||||||
| Alloying elements | Impurities | ||||||||||||
| Standard | Limit | Al | Cu | Mg | Pb | Cd | Sn | Fe | Ni | Si | In | Tl | Zn |
| ASTM B240 (Ingot) | min | 3.9 | 0.75 | 0.03 | – | – | – | – | – | – | – | – | |
| max | 4.3 | 1.25 | 0.06 | 0.004 | 0.003 | 0.002 | 0.075 | – | – | – | – | ||
| ASTM B86 (Cast) | min | 3.5 | 0.75 | 0.03 | – | – | – | – | – | – | – | – | |
| max | 4.3 | 1.25 | 0.06 | 0.005 | 0.004 | 0.003 | 0.1 | – | – | – | – | ||
| EN1774 (Ingot) | min | 3.8 | 0.7 | 0.035 | – | – | – | – | – | – | – | – | |
| max | 4.2 | 1.1 | 0.06 | 0.003 | 0.003 | 0.001 | 0.02 | 0.001 | 0.02 | – | – | ||
| EN12844 (Cast) | min | 3.7 | 0.7 | 0.025 | – | – | – | – | – | – | – | – | |
| max | 4.3 | 1.2 | 0.06 | 0.005 | 0.005 | 0.002 | 0.05 | 0.02 | 0.03 | – | – | ||
| JIS H2201 (Ingot) | min | 3.9 | 0.75 | 0.03 | – | – | – | – | – | – | – | – | |
| max | 4.3 | 1.25 | 0.06 | 0.003 | 0.002 | 0.001 | 0.075 | – | – | – | – | ||
| JIS H5301 (Cast) | min | 3.5 | 0.75 | 0.02 | – | – | – | – | – | – | – | – | |
| max | 4.3 | 1.25 | 0.06 | 0.005 | 0.004 | 0.003 | 0.01 | – | – | – | – | ||
| AS1881 | min | 3.9 | 0.75 | 0.04 | – | – | – | – | – | – | – | – | |
| max | 4.3 | 1.25 | 0.06 | 0.003 | 0.003 | 0.001 | 0.05 | – | 0.001 | 0.0005 | 0.001 | ||
| GB8738-88 | min | 3.9 | 0.7 | 0.03 | – | – | – | – | – | – | – | – | |
| max | 4.3 | 1.1 | 0.06 | 0.004 | 0.003 | 0.0015 | 0.035 | – | – | – | – | ||
| Zamak 5 properties | ||
| Property | Metric value | Imperial value |
| Mechanical properties | ||
| Ultimate tensile strength | 331 MPa (270 MPa aged) | 48,000 psi (39,000 psi aged) |
| Yield strength (0.2% offset) | 295 MPa | 43,000 psi |
| Impact strength | 52 J (56 J aged) | 38 ft-lbf (41 ft-lbf aged) |
| Elongation at Fmax | 2% | |
| Elongation at fracture | 3.6% (13% aged) | |
| Shear strength | 262 MPa | 38,000 psi |
| Compressive yield strength | 600 MPa | 87,000 psi |
| Fatigue strength (reverse bending 5×108 cycles) | 57 MPa | 8,300 psi |
| Hardness | 91 Brinell | |
| Modulus of elasticity | 96 GPa | 14,000,000 psi |
| Physical properties | ||
| Solidification range (melting range) | 380—386 °C | 716—727 °F |
| Density | 6.7 kg/dm3 | 0.24 lb/in3 |
| Coefficient of thermal expansion | 27.4 μm/m-°C | 15.2 μin/in-°F |
| Thermal conductivity | 109 W/mK | 756 BTU-in/hr-ft2-°F |
| Electrical resistivity | 6.54 μΩ-cm at 20 °C | 2.57 μΩ-in at 68 °F |
| Latent heat (heat of fusion) | 110 J/g | 4.7×10−5 BTU/lb |
| Specific heat capacity | 419 J/kg-°C | 0.100 BTU/lb-°F |
| Coefficient of friction | 0.08 | |
Zamak 7
Zamak 7 has less magnesium than zamak 3 to increase fluidity and ductility, which is especially useful when casting thin wall components. In order to reduce inter-granular corrosion a small amount of nickel is added and impurities are more strictly controlled.
| Zamak 7 composition per standard | ||||||||||||
| Alloying elements | Impurities | |||||||||||
| Standard | Limit | Al | Cu† | Mg | Pb | Cd | Sn | Fe | Ni‡ | Si | In | Tl |
| ASTM B240 (Ingot) | min | 3.9 | – | 0.01 | – | – | – | – | – | – | – | – |
| max | 4.3 | 0.1 | 0.02 | 0.002 | 0.002 | 0.001 | 0.075 | – | – | – | – | |
| ASTM B86 (Cast) | min | 3.5 | – | 0.005 | – | – | – | – | 0.005 | – | – | – |
| max | 4.3 | 0.25 | 0.02 | 0.003 | 0.002 | 0.001 | 0.075 | 0.02 | – | – | – | |
| GB8738-88 | min | 3.9 | – | 0.01 | – | – | – | – | 0.005 | – | – | – |
| max | 4.3 | 0.1 | 0.02 | 0.002 | 0.002 | 0.001 | 0.075 | 0.02 | – | – | – | |
| †Impurity ‡Alloying element | ||||||||||||
| Zamak 7 properties | ||
| Property | Metric value | Imperial value |
| Mechanical properties | ||
| Ultimate tensile strength | 285 MPa | 41,300 psi |
| Yield strength (0.2% offset) | 285 MPa | 41,300 psi |
| Impact strength | 58.0 J | 42.8 ft-lbf |
| Elongation at fracture | 14% | |
| Shear strength | 214 MPa | 31,000 psi |
| Compressive yield strength | 414 MPa | 60,000 psi |
| Fatigue strength (reverse bending 5×108 cycles) | 47.0 MPa | 6,820 psi |
| Hardness | 80 Brinell | |
| Physical properties | ||
| Solidification range (melting range) | 381—387 °C | 718—729 °F |
| Coefficient of thermal expansion | 27.4 μm/m-°C | 15.2 μin/in-°F |
| Thermal conductivity | 113 W/m-K | 784 BTU-in/hr-ft2-°F |
| Electrical resistivity | 6.4 μΩ-cm | 2.5 μΩ-in |
| Specific heat capacity | 419 J/kg-°C | 0.100 BTU/lb-°F |
| Casting temperature | 395—425 °C | 743—797 °F |
Everything you need to know about zinc
Everything you need to know about zinc
The elemental metal named zinc is listed on the Periodic Table as “Zn”, has atomic number 30 and melts at 420 degrees Celsius (788 degrees Fahrenheit). The commodity zinc is the 24th most abundant element in the crust of the Earth. Its color is grey metallic and can be polished to a silver shine. In nature, zinc is not found as a pure deposit, but as a chemical compound. The most commonly exploited zinc ore is a sulfide named sphalerite, with a zinc concentration of around 61% percent. The largest deposits of zinc are found in North America, Australia and Asia.
Currently identified zinc resources total about 1.9 billion tonnes, which are estimated to be depleted between 2027 and 2055 at the current rate of consumption.
History of the commodity zinc
Statuettes and other ornaments made of a zinc alloy and some ancient writings, such as Greek, Roman and Indian recordings, mention the use of zinc as early as the 5th century BC. Brass, an alloy made of copper and zinc, was already used in the 14th century BC in Palestine, containing 23% zinc in some specific cases.
The isolation of pure zinc was achieved, probably independently by several people, at the end of the 17th century to as late as the mid 18th century. The German chemist Andreas Marggraf normally gets credit for the discovery of pure zinc in 1746, even though others before him have claimed discovery. Marggraf is therefore credited more with carefully describing the process and its basic theory, than the actual discovery.
The making of zinc
The making of zinc involves a number of steps which are described below.
Mining
Around 70% of the world’s zinc comes from mining, the remaining 30% originates from recycling zinc. Around 95% of the zinc is mined from sulfidic ore deposits and these mines are spread throughout the world. China is the largest producer of zinc, with around 29% of the global zinc output in 2010.
Zinc metal is mined by using conventional blasting, drilling and hauling techniques. Froth flotation is used to separate zinc from other minerals after grinding the ore. The final concentration of zinc is about 50% using this method, the remainder being sulfur and iron.
Froth Flotation
By a process known as froth flotation, zinc can be produced. Froth flotation is also used in the reduction of copper and lead ores. The process starts with grinding the zinc ore to fine material and subsequently mixing it with water, pine oil and flotation chemicals. The flotation chemicals attach themselves to any zinc particles present when the mixture is agitated with injected air. Bubbles rise up with zinc particles adhered to it, which are scooped up by scrapers, thus collecting zinc-laden froth.
To remove water and oils, the froth is filtered. The remainder is roasted at 1371 degrees Celsius (2500 degrees Fahrenheit) into solid blocks called sinter. All the material has been completely converted to zinc oxide.
Refining
There are two methods for refining zinc, which are listed below.
1. Pyrometallurgy
In order to refine the zinc to a higher grade ore it is processed in a blast furnace fueled by electricity, coke or natural gas. As the furnace reaches temperatures of up to 1204 degrees Celsius (2200 degrees Fahrenheit) the zinc ore is melted. This process also generates carbon dioxide, which will reattach to the zinc as it cools to, once again, form zinc oxide. To prevent, or at least reduce, this reattachment, molten lead is sprayed on the zinc while it is still hot. The lead, because of its higher melting temperature of 550 degrees Celsius (1022 degrees Fahrenheit), dissolves the zinc. This mostly lead and zinc mixture is then carried to another chamber, where it will be cooled to 440 degrees Celsius (824 degrees Fahrenheit). Around this temperature, the zinc, because it is lighter, separates from the lead and is drained from the top. Subsequently it is cast into ingots. The lead is returned to the blast furnace to use again.
To reach an even higher grade zinc ore, the zinc is kept molten and undisturbed for hours. Iron and other contaminants will settle slowly to the bottom, thus allowing the almost pure zinc to be drained from the top.
With pyrometallurgical processes a maximum purity of 98% can be achieved. While this is high enough to use the zinc for galvanization, it cannot be used to die-cast alloys, which requires 99,995% purity.
2. Hydrometalllurgy
The hydrometallurgical process, also known as electrolysis, is used a lot more than the pyrometallurgical process. It consists of four steps: leaching, purifying, electrolysis and casting.
In the first step, the zinc oxide is leached in a strong sulfuric. The result is a liquid called a leach product, which contains the zinc. It also produces a solid called a leach residue, which contains left-over metals (usually lead and silver) and is sold as a by-product. The basic chemical process is: ZnO + SO3 –> ZnSO4. The second step is called purification, because it removes certain elements from the zinc sulfate solution which can interfere with the electrolysis process. copper, cobalt, cadmium and nickel are removed and sold as by-products for further refining. The zinc sulfate solution must be very pure for electro-winning to be efficient.
Electrolysis is the third step, producing an almost 100% pure zinc deposit. The commodity zinc is extracted from the zinc sulfate solution by electrowinning. An electric current is passed through the solution, which causes the zinc to deposit on aluminium sheets. Every day or two, the process is halted and the zinc-coated sheets are removed. Subsequently, the zinc is stripped from the sheets. About 3,900 KWh of electric power is expended producing one metric ton of zinc in this way. The final step is to melt the high grade zinc and cast it into very high grade (99,995% purity) ingots, or directly alloy and cast it into ingots.
Transportation
The commodity zinc is usually transported in very large quantities on commercial shipping freighters, with the part between port and destination done by train or truck.
Applications of the commodity zinc
Zinc is used in a number of applications.
1. Galvanizing against corrosion
Zinc is commonly used to coat iron or steel to protect these metals against corrosion. As it is more reactive than iron or steel, zinc will attract almost all oxidation until corrosion completely erodes the coated sheet. What is left is a surface protection layer of oxide and carbonate. This protection even functions after minor scratches and dents and can survive for many years.
Galvanization is used on metal roofing, bridges, guard rails, lightposts, heat exchangers and most visible to the consumer: car bodies.
Coating zinc on another metal is accomplished by electrolytic plating of the metal – much like chrome plating a metal – or dipping it into molten zinc.
2. Intricate machine parts
An alloy made of very high grade zinc and aluminium is used to create die-cast parts which require little machining before they are used in an assembly. By injecting the alloy under pressure into the cavity of a two-part steel die, it fills the entire void within the mold. After the metal cools and the die halves are taken apart, the resulting zinc-alloy part is very close to the desired shape.
Die-casting is used, among others, to create parts for aircraft, medical instruments and car parts like emblems and doorhandles.
3. Electrodes
An unique application of zinc uses its ability to transfer its corrosion resistance properties by electrical contact. In this manner, zinc is used as a sacrificial electrode. An example application for this kind of electrode is when it is attached to aluminium marine engines. Especially in salt water, the oxidation process of the metals on the ship forms a weak electrical current, which may lead to corrosion of the hull and engine parts. By having a zinc sacrificial electrode present, it sacrifices itself by corrosion, negating the electrical current and thus protecting the aluminium hull and/or engine.
Similarly, zinc is used as a component to produce batteries. In a dry cell battery, the zinc is housed in a metal can and creates a chemical reaction that results in a voltage potential between two contacts. An electrical device can be connected to the battery and powered by the electricity produced, until the available chemical reactants are spent.
4. Alloys
One widely used alloy which contains a large amount of zinc is brass. Brass is an alloy of copper mixed with 3% to 45% zinc, depending on the type of brass. Brass is superior to copper in areas like ductability, strength and corrosion resistance. This makes it useful in water valves, musical instruments and communication equipment. Other used alloys that contain substantial amounts of zinc include aluminium solder, commercial bronze and nickel silver. It is also the primary metal used in producing one cent coins in the United States. The zinc coin is coated with a layer of copper to give the false impression of a copper coin.
Trading
Zinc is usually transported in very large quantities on commercial shipping freighters, with the part between port and destination done by train or truck.
Price factors
Zinc futures prices are influenced by a number of factors. Global supply of the commodity zinc is a major price determining factor. In the case of over-production, prices will rapidly fall. Mining activities will consequently drop which will eventually cause a deficit in supply. This will again raise prices to a standard level and this cycle will repeat itself.
Substitutes can also greatly influence the demand for zinc. Metals such as aluminum and magnesium are alternatives as die-cast materials and as such can influence price movements of zinc. In the event of rising prices of aluminum and magnesium the demand for zinc will increase.
Production and refining methods for zinc are also influencing prices as these processes are becoming ever increasingly cost-effective. This will increase the supply of available zinc and thus lower the price of this metal.
Limited remaining deposits can cause difficulties on the supply of zinc in the future. In comparison to various precious metals and base metals, zinc has a lower return yield which is why very limited budget is spent on the exploration of new zinc deposits. This may cause a deficit in the long term, which will eventually raise prices.
LME Zinc Futures Contract
A Zinc Futures Contract on the London Metal Exchange (LME) has the following specifications: