[raymanh]

As per the title, can FeS2 be oxidised by Fe(OH)3 and if so what would the equation look like?

[Hunter2]

I dont think so.  Iron-III-hydroxide has to be reduced and the sulfur oxidised. That means iron-II should be created, this is in nature seldom.

[Miles]

First, Iron (III) hydroxide is not well defined. It is thought to be Iron (III) oxide hydroxide hydrate FeO(OH).H2O.

Second, you have a phase issue here as reacting two solids is often difficult.

But when Iron(III) is in solution like in ferric chloride, disulfide is oxidized to elemental sulfur while Iron(III) is reduced to Iron(II).

Have a look at how chalcopyrite (CuFeS2) is processed in the copper mining industry.