Editing Zinc (section)

==Production==

===Mining and processing===
{| class="wikitable" style="float:right; margin-left:0.5em"
|+ Top zinc mine production output (by countries) 2023<ref>[https://pubs.usgs.gov/periodicals/mcs2024/mcs2024-zinc.pdf Mineral Commodity Summaries 2024]</ref>
|- class="hintergrundfarbe6"
! [[Ranking|Rank]] !![[Country]] !![[Tonne]]s
|-
| '''1'''||'''[[China]]''' ||align="right"| '''4,000,000'''
|-
| '''2'''||'''[[Peru]]''' ||align="right"| '''1,400,000'''
|-
| '''3'''||'''[[Australia]]''' ||align="right"| '''1,100,000'''
|-
| '''4'''||'''[[India]]'''|| align="right" | '''860,000'''
|-
| '''5'''||'''[[United States]]'''|| align="right" | '''750,000'''
|-
| '''6'''||'''[[Mexico]]''' ||align="right"| '''690,000'''
|}
{{Main|Zinc mining|Zinc smelting}}
{{See also|List of countries by zinc production}}
[[File:Price of Zinc.webp|thumb|325px|right|Price of Zinc]]
[[File:World Zinc Production 2006.svg|thumb|upright=1.6|Percentage of zinc output in 2006 by countries<ref name="USGSCS2008">{{cite web|url=http://minerals.er.usgs.gov/minerals/pubs/commodity/zinc/mcs-2008-zinc.pdf|first=Stephen M.|last=Jasinski|publisher=United States Geological Survey|access-date=November 25, 2008|title=Mineral Commodity Summaries 2007: Zinc|url-status=live|archive-url=https://web.archive.org/web/20081217021239/http://minerals.er.usgs.gov/minerals/pubs/commodity/zinc/mcs-2008-zinc.pdf|archive-date=December 17, 2008}}</ref>|alt=World map revealing that about 40% of zinc is produced in China, 20% in Australia, 20% in Peru, and 5% in US, Canada and Kazakhstan each.]]

[[File:Zinc world production.svg|thumb|lang=en|World production trend]]
[[File:Zink Mine Rosh Pinah.jpg|thumb|Zinc Mine Rosh Pinah, [[Namibia]]<br />{{coord|27|57|17|S|016|46|00|E|region:NA_type:landmark|name=Rosh Pinah}}]]
[[File:Skorpion Zink Mine.jpg|thumb|Zinc Mine Skorpion, [[Namibia]]<br />{{coord|27|49|09|S|016|36|28|E|region:NA_type:landmark|name=Skorpion}}]]

Zinc is the fourth most common metal in use, trailing only [[iron]], [[aluminium]], and [[copper]] with an annual production of about 13 million tonnes.<ref name="USGSMCS2015" /> The world's largest zinc producer is [[Nyrstar]], a merger of the Australian [[OZ Minerals]] and the Belgian [[Umicore]].<ref>{{cite web|url=https://www.wsj.com/articles/SB116590371844647445|title=Zinifex, Umicore Combine to Form Top Zinc Maker|last=Attwood|first=James|work=[[The Wall Street Journal]]|date=February 13, 2006|url-status=live|archive-url=https://web.archive.org/web/20170126122526/http://www.wsj.com/articles/SB116590371844647445|archive-date=January 26, 2017}}</ref> About 70% of the world's zinc originates from mining, while the remaining 30% comes from recycling secondary zinc.<ref>{{cite web|url=http://www.zincworld.org/recycling.html |title=Zinc Recycling |publisher=International Zinc Association |access-date=November 28, 2008 |url-status=dead |archive-url=https://web.archive.org/web/20111021135539/http://www.zincworld.org/recycling.html |archive-date=October 21, 2011 }}</ref>

{{anchor|Commercially pure zinc}}
Commercially pure zinc is known as Special High Grade, often abbreviated ''SHG'', and is 99.995% pure.<ref>{{cite web|title=Special High Grade Zinc (SHG) 99.995%|url=http://nyrstar.com/nyrstar/en/products/zinccongalvanising/techdownloads/shg_budel.pdf|archive-url=https://web.archive.org/web/20090304154218/http://nyrstar.com/nyrstar/en/products/zinccongalvanising/techdownloads/shg_budel.pdf|archive-date=March 4, 2009| access-date=December 1, 2008|date=2008|publisher=Nyrstar}}</ref>

Worldwide, 95% of new zinc is mined from [[sulfide|sulfidic]] ore deposits, in which sphalerite (ZnS) is nearly always mixed with the sulfides of copper, lead and iron.<ref name="Zinchand" />{{Rp|page=6}} Zinc mines are scattered throughout the world, with the main areas being China, Australia, and Peru. China produced 38% of the global zinc output in 2014.<ref name="USGSMCS2015" />

Zinc metal is produced using [[extractive metallurgy]].<ref name="Rosenqvist1922">{{Cite book|title=Principles of Extractive Metallurgy|last=Rosenqvist|first=Terkel|pages=7, 16, 186|edition=2nd|date=1922|isbn=978-82-519-1922-7|publisher=Tapir Academic Press}}</ref>{{Rp|page=7}} The ore is finely ground, then put through [[froth flotation]] to separate minerals from [[gangue]] (on the property of [[hydrophobicity]]), to get a zinc sulfide ore concentrate<ref name="Rosenqvist1922" />{{Rp|page=16}} consisting of about 50% zinc, 32% sulfur, 13% iron, and 5% {{chem|SiO|2}}.<ref name="Rosenqvist1922" />{{Rp|page=16}}

[[Roasting (metallurgy)|Roasting]] converts the zinc sulfide concentrate to zinc oxide:<ref name="Zinchand">{{Cite book|url=https://books.google.com/books?id=laACw9i0D_wC|title=Zinc Handbook|first=Frank C.|last=Porter|publisher=CRC Press|date=1991|isbn=978-0-8247-8340-2}}</ref>
:<chem>2ZnS + 3O2  ->[t^o] 2ZnO + 2SO2</chem>

The [[sulfur dioxide]] is used for the production of sulfuric acid, which is necessary for the leaching process. If deposits of [[zinc carbonate]], [[zinc silicate]], or [[zinc-spinel]] (like the [[Skorpion Zinc|Skorpion Deposit]] in [[Namibia]]) are used for zinc production, the roasting can be omitted.<ref name="Skorpion">{{Cite journal|journal=Economic Geology|date=2003|volume=98|issue=4|pages=749–771|doi=10.2113/98.4.749|title=Geology of the Skorpion Supergene Zinc Deposit, Southern Namibia|first=Gregor|last=Borg|author2=Kärner, Katrin |author3=Buxton, Mike |author4=Armstrong, Richard |author5= van der Merwe, Schalk W. }}</ref>

For further processing two basic methods are used: [[pyrometallurgy]] or [[electrowinning]]. Pyrometallurgy reduces zinc oxide with [[carbon]] or [[carbon monoxide]] at {{convert|950|C|F|abbr=on}} into the metal, which is distilled as zinc vapor to separate it from other metals, which are not volatile at those temperatures.<ref>{{Cite book|last=Bodsworth|first=Colin|title=The Extraction and Refining of Metals|page=148|date=1994|isbn=978-0-8493-4433-6|publisher=CRC Press}}</ref> The zinc vapor is collected in a condenser.<ref name="Zinchand" /> The equations below describe this process:<ref name="Zinchand" />

: <chem>ZnO + C ->[950^oC] Zn + CO</chem>
: <chem>ZnO + CO ->[950^oC] Zn + CO2</chem>

In [[electrowinning]], zinc is leached from the ore concentrate by [[sulfuric acid]] and impurities are precipitated:<ref>{{Cite book|title=Hydrometallurgy in Extraction Processes|last=Gupta|first=C. K.|author2=Mukherjee, T. K. |page=62|publisher=CRC Press|isbn=978-0-8493-6804-2|date=1990}}</ref>

:<chem>ZnO + H2SO4 -> ZnSO4 + H2O</chem>

Finally, the zinc is reduced by [[electrolysis]].<ref name="Zinchand" />

:<chem>2ZnSO4 + 2H2O -> 2Zn + O2 + 2H2SO4</chem>

The sulfuric acid is regenerated and recycled to the leaching step.

When galvanised feedstock is fed to an [[electric arc furnace]], the zinc is recovered from the dust by a number of processes, predominantly the [[Waelz process]] (90% as of 2014).<ref>{{citation| title = Handbook of Recycling: State-of-the-art for Practitioners, Analysts, and Scientists| editor-first = Ernst| editor-last = Worrell| editor-first2= Markus|editor-last2= Reuter| date = 2014| chapter =9. Zinc and Residue Recycling| first1 = Jürgen| last1 = Antrekowitsch| first2= Stefan| last2= Steinlechner| first3 = Alois| last3= Unger| first4 = Gernot| last4 = Rösler| first5 = Christoph| last5 = Pichler| first6 = Rene| last6 = Rumpold}}</ref>

===Environmental impact===
Refinement of sulfidic zinc ores produces large volumes of sulfur dioxide and [[cadmium]] vapor. Smelter [[slag]] and other residues contain significant quantities of metals. About 1.1&nbsp;million tonnes of metallic zinc and 130 thousand tonnes of lead were mined and smelted in the Belgian towns of [[Kelmis|La Calamine]] and [[Plombières]] between 1806 and 1882.<ref name="Kucha">{{Cite journal|journal=Environmental Geology|date=1996|volume=27|first=H.|last=Kucha|issue=1|author2=Martens, A.|author3=Ottenburgs, R.|author4=De Vos, W.|author5=Viaene, W.|title=Primary minerals of Zn-Pb mining and metallurgical dumps and their environmental behavior at Plombières, Belgium|doi=10.1007/BF00770598|pages=1–15|bibcode=1996EnGeo..27....1K|s2cid=129717791}}</ref> The dumps of the past mining operations leach zinc and cadmium, and the sediments of the [[Geul River]] contain non-trivial amounts of metals.<ref name="Kucha" /> About two thousand years ago, emissions of zinc from mining and smelting totaled 10 thousand tonnes a year. After increasing 10-fold from 1850, zinc emissions peaked at 3.4&nbsp;million tonnes per year in the 1980s and declined to 2.7&nbsp;million tonnes in the 1990s, although a 2005 study of the Arctic troposphere found that the concentrations there did not reflect the decline. Man-made and natural emissions occur at a ratio of 20&nbsp;to&nbsp;1.<ref name="Broadley2007" />

Zinc in rivers flowing through industrial and mining areas can be as high as 20&nbsp;ppm.<ref name="Emsley2001p504">{{harvnb|Emsley|2001|p=504}}</ref> Effective [[sewage treatment]] greatly reduces this; treatment along the [[Rhine]], for example, has decreased zinc levels to 50&nbsp;ppb.<ref name="Emsley2001p504" /> Concentrations of zinc as low as 2&nbsp;ppm adversely affects the amount of oxygen that fish can carry in their blood.<ref>{{Cite book|last=Heath|first=Alan G.|title=Water pollution and fish physiology|publisher=CRC Press|location=Boca Raton, Florida|date=1995|page=57|isbn=978-0-87371-632-1|url=https://books.google.com/books?id=5NPVTuBtGF4C}}</ref>

{{wide image|The Zinc Works and Incat.jpg|1150px|Historically responsible for high metal levels in the [[Derwent River (Tasmania)|Derwent River]],<ref>{{cite web|url=http://www.derwentestuary.org.au/file.php?id=193 |title=Derwent Estuary&nbsp;– Water Quality Improvement Plan for Heavy Metals |date=June 2007 |publisher=Derwent Estuary Program |access-date=July 11, 2009 |url-status=dead |archive-url=https://web.archive.org/web/20120321090648/http://www.derwentestuary.org.au/file.php?id=193 |archive-date=March 21, 2012 }}</ref> the zinc works at [[Lutana]] is the largest exporter in Tasmania, generating 2.5% of the state's [[Gross domestic product|GDP]], and producing more than 250,000 tonnes of zinc per year.<ref>{{cite web|title=The Zinc Works|url=http://www.tchange.com.au/resources/zinifex_smelter.html|publisher=TChange|access-date=July 11, 2009|url-status=live|archive-url=https://web.archive.org/web/20090427031313/http://www.tchange.com.au/resources/zinifex_smelter.html|archive-date=April 27, 2009}}</ref>|alt=A panorama featuring a large industrial plant on a sea side, in front of mountains.}}

[[soil contamination|Soils contaminated]] with zinc from mining, refining, or fertilizing with zinc-bearing sludge can contain several grams of zinc per kilogram of dry soil. Levels of zinc in excess of 500&nbsp;ppm in soil interfere with the ability of plants to absorb other [[Dietary mineral|essential metals]], such as iron and [[manganese]]. Zinc levels of 2000&nbsp;ppm to 180,000&nbsp;ppm (18%) have been recorded in some soil samples.<ref name="Emsley2001p504" />