# Why does production of nickel and copper metals from their ores involve sulfur dioxide emissions?

Aug 7, 2018

Well, nickel ores, and copper ores are COMMONLY sulfides...

#### Explanation:

Please bear in mind that I am a non-specialist, however, nickel is commonly encountered as a MIXED sulfide with iron, i.e. $\text{pentlandite}$, i.e. ${\left(F e , N i\right)}_{9} {S}_{8}$. And chalcocite, $C {u}_{2} S$, and chalcopyrite, $C u F e {S}_{2}$ are common copper ores. And if we roast the ores in the presence of oxygen...

$C {u}_{2} S \left(g\right) + 2 {O}_{2} \left(g\right) \stackrel{\Delta}{\rightarrow} 2 C u O \left(s\right) + S {O}_{2} \left(g\right) \uparrow$

...the copper oxide is produced, which may be reduced to copper metal, and up the flue we get sulfur dioxide.... i.e. the sulfur in the ore is OXIDIZED...

${S}^{2 -} + 2 {H}_{2} O \left(l\right) \rightarrow S {O}_{2} \left(g\right) + 4 {H}^{+} + 6 {e}^{-}$