How to purify silver upto a finess of .995 or .999

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In india gold and silver are a lot traded as ornaments.when this ornaments are to be re purified for making new ornaments they are of melting percentages of 10% to 99% with mixing of copper in lot amount ,zinc,nickel and etc.so is there any lab process to purify this silver @ 5,000 gms to 15,000 gms per day in which all the mixing metals may be copper also can be retracted from it while purifying the silver.is it possible