[happyprince]

 Hi everybody,
  I can precipitate gold dissolved in aqua regia if the gold is just pure.I use sodium metabisulfite.However,if I dissolve the gold from ore in aqua regia,I cannot precipitate the gold.What's wrong?Might other metals or mud in the soil spoil it?Does anything prevent precipitating?Any help will be highly appreciated.Thanks a lot in advance.

[Arkcon]

There may be very little gold in gold ore.  You may not be attacking all of it with the aqua regia, if its in silicate or or black sand.  Even if you are, you may be precipitating vanishingly small amounts of gold dust, not even enough to see.  What you have to do is form a gold concentrate -- form a gold-cyanide complex or gold-mercury amalgam from tons of ore, just keep using the same reagent over and over on new batches of ore.  Then you'll process the concentrate for a visible quantity of gold.

[happyprince]

actually I am pretty sure that there is big amount of gold in  the ore.There must be another method to precipitate the gold:

[ajkoer]

A related methods uses SO2, and not so related employs Oxalic acid (careful: poisonous read its MSDS). However, to be honest, I am suspicious of your 'gold' source.