Dear SonuBhai,
If u have nitric acid than try too dissolve the "alloy" in it, the residue will be gold in a dark brown/black powder. If you havent got any Nitric than u must make a cupel first.
To make a cupel is very easy get some bones, some dry wood and in a furnace burn it down (in the fire it should have an orange color for 30 min). U will be left with calcined bones, note that the bones should be very crumbly, if they arent than burn it a nother time. Next crush the bones to a fine powder (fine as flour), wash out carefull with water (salt like NaCl, Na2CO3, KCl ... will make trouble) and dry it half way, than press it together the upper side should have a depression where your lead alloy will be oxidized (and leave you with a nice snow white prill).
Next dry it slowly min one week (best 2-3 weeks) than heat it up till its yellow than let it cool and its ready tho use ,if it cracks crush it down too powder press it in an iron/steel container.
Place the raw gold/silver/copper/lead alloy in the cupel put about the same wheight of lead (best would be 4-5 times the weigh of your raw alloy if it contains many copper). Place it in a furnace heat it up to 900 Celsius( orange color, 880 too 950 Celsius max, over 960 Celsius Silver will melt and spit from atmosferic oxigen) and keep the temperature. U will notice that the lead will have a skin like surface wich will be sought in to the bone ash dish, finaly as the cupelation progresses there wont be any lead left and in that moment a courtain drag like phenomenon will occur>>>>> the orange alloy will cool down in an instant and there will be your noble metal prill with minor base metals (less than 0,5 %).
To separate the gold from silver:
A. u will have too use nitric acid or hot/boiling sulfuric acid.
B. the cementation proces:
1. make a very thin sheet from your metal prill,
2.place it in a clay crucible
3. 2 x salt, vinegar/urin and 2x powdered brick mix till it has a paste like consistency
4.Mix the paste and the thin metal foil/foils
5. Seal the clay crucible put it near the fire, max. cherry red or your silver is lost.
6. Let it there for 6 to 8 hours,
7. Repeat till u have only gold left ( if u want pure gold), pan it out and there is your gold.
8. Get the residue separated from you gold, put 2 x weight Na2CO3 and 0,5 wheight borax, 0,2 flour/carbon, mix it, put it in a crucible heat it gently too 1100 Celsius (white hot, 1000 is enough), be carefull the temperature should be held for 20 min around 600 too 800 Celsius than heat it too 1100 pour too a mold and ther is your fine silver.
I have used min. 4 gram silver, dont now how much u have, if it is less than a gram dont bother yourself whit it.
Hope it helps.
P.s. Sorry for my spelling english is my 3 language. Be carefull at the cupellation process lead will vaporize (about 1 to 0.5 % or more) so make it outside far from your "kitchen", the wind should blow from your back, wear a gas mask or u will get a nice blue line next to your teeth, on your gum.