# How is mercury produced in industry? [closed]

Mercury is the only metal that exists in a liquid state at room temperature.

• In which form is mercury extracted from its ore?
• If it produced as a solid, how and when is it turned into a liquid?

## closed as off-topic by Todd Minehardt, airhuff, Jon Custer, Klaus-Dieter Warzecha, M.A.R.Mar 4 '17 at 7:07

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• There are many solid compounds that include mercury as one of their constituents. But, pure mercury at room temperature is a liquid as you point out. – Jon Custer Feb 3 '17 at 14:05
• tell me ik at room temperature it is liquid tell me in which state we get it from its ore.... that's my question – Utsav pandey Feb 3 '17 at 14:10
• The classic way is to roast the ore, with the mercury coming off as a vapor that is readily condensed. Note that vaporized mercury is easily taken up by humans and damages the central nervous system. – Jon Custer Feb 3 '17 at 14:13
• I'll point out that most Hg now recovered in the US is as a byproduct to prevent pollution rather than being mined for the Hg itself. archive.epa.gov/mercury/archive/web/pdf/… – MaxW Feb 3 '17 at 16:27

Most commonly, mercury $\ce{Hg}$ is separated from its ore $\ce{HgS}$, known as cinnabar. The process used is roasting; this entails heating the raw material in oxygen.

$$\ce{HgS(l) + O2(g) ->[700-800\ ^\circ \mathrm{C}] Hg(g) + SO2(g)}$$

Mercury is extracted here in the gaseous state. Note that the product is elemental mercury, not an oxide. This is because the oxides decompose at or below $500\ ^\circ \mathrm{C}$: $$\ce{Hg2O -> HgO + Hg,\\ HgO -> Hg + O2}.$$

The mercury vapor is then purified in multiple steps which depend on the required degree of purity. Usually the gaseous mercury is first cleansed from dust, then condensed (bp $356.6\ ^\circ \mathrm{C}$). At this stage, an $80\%$ yield is observed.

The condensed mass is filtered further, washed with bases and acids, and destilled. For ultrapure mercury (less than $10^{-6}\%$ of impurities), electrochemical refinement using mercury electrodes follows.

Hergi Karik, Kalle Truus. ($2003$). Elementide keemia. (pp 331$-$332, 334)

• it means cinnabar exist in liquid state so how it is extracted from earth – Utsav pandey Feb 3 '17 at 14:44
• @Utsavpandey No, cinnabar is a solid ore at standard conditions. The states are written in accordance with the reaction; the sulfide simply melts before $700-800\ ^\circ \mathrm{C}$. – Linear Christmas Feb 3 '17 at 14:53

Mercury is extracted from its ore, cinnabar($\ce{HgS}$). According to wikipedia:

Mercury is extracted by heating cinnabar in a current of air and condensing the vapor. The equation for this extraction is

$$\ce{HgS + O2 → Hg + SO2}$$

In 2005, China was the top producer of mercury with almost two-thirds global share followed by Kyrgyzstan. Several other countries are believed to have unrecorded production of mercury from copper electrowinning processes and by recovery from effluents.