Pricing Refining Services

First off, do you really know how to refine? Can you produce gold of acceptable quality? If not, accepting his material can prove to be a fatal mistake. One of my best advertisers was a friend that was slip shod in his refining techniques, and refused to change. As he supplied low quality gold to his customers, who he had pursed with vigor, they slowly quit using his services, at which time he'd give them my name. I ended up with his entire customer base because he was inept. Please keep that in mind. You must be able to walk before you can run. OK--my sermon is over----I hope it served a purpose. I charged 10% for refining bench sweeps and solids unless the yield exceeded 10 troy ounces,at which time I made an adjustment, and did the work for 8%. It is a fair fee, but there were no other hidden charges, and I DID NOT steal customer values. That's the other big mistake refiners like to make. My fee was in the way of withholding the metal. I did not accept cash payment. That insures you get paid. I refined polishing wastes and floor sweeps for a 15% fee. You earn the money on this stuff, it's labor intensive. Carpet fee was 50%----and it can be a losing proposition at that price. All depends on the carpet.

Nitric Acid

Concentrate Nitric Acid

H2SO4 + 2 NaNO3 --> Na2SO4 + 2HNO3

The big difference in my recipie is the solubility of the sodium sulfate salt (as opposed to sodium hydrogen sulfate you produce) and the fact that my equation yields twice the nitric acid at a higher temperature ( no dry ice, just salted ice ).

I've run the numbers like you did and ended up with about 160 mL of 50% nitric (give or take a few percent) for a single mole of 96% sulfuric and using 100mL H2O to dissolve the nitre.

I won't bore everyone with the math, but here's my summary.

Reaction:

• Bring 100 mL of Distilled Water in a 500 mL pyrex beaker to 100 C
• Add the Nitre of your choice (202 gm K / 170 gm Na)
• Stir until Nitre is completely dissolved, let cool below boiling
• SLOWLY add 56 mL conc (96%+) Sulfuric Acid to Hot Nitre solution while stirring, DON'T allow the solution to boil!
• Allow solution to cool to room temp (DO NOT SKIP - VESSEL WILL SHATTER IF PUT ON ICE WHILE HOT!!!)
• When vessel reaches room temp (25 °C) put the vessel in the freezer or on a salt water ice bath
• Let stand until temperature of mixture reaches -5 °C
• Let stand at -5 °C until all percipitate settles
• Pour the COLD solution off into glass container with tightly sealed lid DO NOT POUR OFF ANY OF THE SALT IN THE BOTTOM!!!
• Makes ~160 mL ~50% HNO3
K= Potassium NA= Sodium

This acid in turn can be used to make true AR with the standard 4:1 recipie (HCl:HNO3).

Chemical Formula

Chemical Formula to Dissolve and Precipitate Metal

All, there seems to be a lot of confusion on the various acid mixtures used in the different reactions. Here's a quick Chemical formula to dissolve and precipitate Metal :

1.AR= Aqua Regia = 1 part 70% Nitric Acid, 3 parts Muriatic Acid (some guys use 4 parts muriatic). Used to dissolve high karat gold, gold powder, gold foils, dissolves Platinum when hot. Excess nitric must be neutralized with Urea to pH 1 +/- 0.4, then drop gold with SMB (Sodium Meta Bisulfite).

•Hoke states 4 fluid ounces HCl + 1 fluid ounce HNO3 dissolves 1 troy ounce gold. This is equivalent to 31 mL HCl + 8 mL HNO3 per gram of gold.

2.AR Recipie 2= Poor Man's AR = 8 oz Sodium Nitrate, 480 ml water, 960 ml Muriatic Acid plus heat. Used to dissolve high karat gold, gold powder, gold foils, dissolves Platinum when hot. Excess nitric must be neutralized with Urea to pH 1 +/- 0.4, then drop gold with SMB.

•The above mentioned recipie makes enough AR to dissolve 160 gm Pins or 32 oz of ceramic cpus.

3.HCl-Cl= Clorox Method = 4 Parts Muriatic, 1 Part Clorox (added in small increments). Used to dissolve gold foils and powder. Drop gold with SMB, NO urea needed.

4.AP= Acid Peroxide = 2 Parts Muriatic Acid, 1 Part 3% Hydrogen Peroxide. Dissolves base metals, slowly dissolves gold when heated. If gold is present drop with SMB, NO urea needed.

5.Dilute HNO3=Dilute Nitric Acid= 1 part water, 1 part 70% Nitirc Acid. Used to inquart, dissolve base metals, dissolves palladium, and dissolves silver. Silver nitrate will stain skin blue which turns black in sunlight. Skin remains black for nearly 1 week.

•Hoke states 4-6 pounds of concentrated nitric acid dissolves 1 pound of base metals. 5 pounds of 70% nitric, 1.41 sp.gr. is 1610 mL =~ 0.425 gallons.

6.H2SO4= Sulfuric Acid = 1 cup 96%+ Sulfuric, 1/8 tsp glycerin. Used as electrolyte in electrolytic cell along with a small amount of glycerin. Effective on medium to large gold plated items. With specially designed anodes and cathodes large batches of smaller plated items can be processed. Not used for Gold filled or karat jewelry.

•Use until acid is saturated with black powder typically 12-24 hours of operation. Sink any floating black powder, let settle overnight, pour off bulk of acid for reuse, and dilute remaining acid with 4 parts water.

7.HCl= Muriatic Acid = 31.45% Hydrochloric Acid. Used in the crockpot method and for general cleanup of gold foils and powders. Dissolves base metals. Also used in making stannous chloride gold testing solution.

8.SMB= Sodium Meta Bisulfite plus water=28.3 Grams Sodium Meta Bisulfite, 240 ml H2O. Used to precipitate/drop gold from gold bearing solutions.

•Add 65 grams to 100 ml water for saturated solution. Add to pregnant solution until stannous chloride test on solution is negative for gold.

9.AuCl3= Auric Chloride= Term used to describe gold dissolved into solution. Typically imparts a golden yellow color to solutions. Stains skin and other organics purple.

10.SnCl2= Stannous Chloride= Used to test solutions for precious metals. Made by dissolving metallic tin in hot muriatic acid. Loses strength when stored. Stannous Chloride, SnCl2.2H2O.—The crystals are best purchased. If kept dry and free from air they are fairly permanent. A solution is made by dissolving 20 grams in 10 c.c. of hydrochloric acid and diluting to 1 litre. The solution is not permanent. It is a strong reducing agent, and is chiefly used in solution for this purpose.

Positive color test as follows:

•Purple/Black color is Gold in solution, the darker the spot the more Gold.

•Yellow/Brown color is Palladium in solution, the darker the spot the more Palladium.

•Light/Dark Rose color is Platinum in solution, the darker the spot the more Platinum.

11.(NH2)2CO= Urea= 8 oz Urea, 480 mL Water. Used to neutralize excess nitric acid in AR process before dropping gold with SMB. Add until solution doesn't fizz and pH reaches 1 +/- 0.4.

12.AgCl= Silver Chloride= White precipitate that forms when silver is exposed to chlorine in solution. Turns purple in light, darkens further in sunlight. Solid by product of using AR on lower karat jewelry. Hazardous to melt due to fumes. Production of silver chloride should be avoided if possible. Can be converted to silver metal with lye and karo syrup or HCl and Al foil.

•For 1 tr.oz. of silver metal, about 41.5 grams of silver chloride, it takes about 20 grams of sodium hydroxide, 13.3 mL of light Karo syrup, and 133 mL of water.

13.Inquartation= 3 parts base metal (Silver perferred) , 1 part Gold, Dissolved in hot dilute nitric acid. Powder/Honeycomb that remains is Gold and higher PGM's if present in source material. Left over liquid contains Silver, base metals, and Palladium if present in original alloy.

•Hoke states 4-6 pounds of concentrated nitric acid dissolves 1 pound of base metals. 5 pounds of 70% nitric, 1.41 sp.gr. is 1610 mL =~ 0.425 gallons.

11.C12H26O3 = BDG or DBC= Butyl DiGlyme or DiButyl Carbitol = Organic solvent that combines with Auric Chloride and is insoluble in water based solutions. Separates from water based solutions as an upper phase (layer). After washing with dilute HCl gold is dropped as flakes using Oxalic Acid. Can be used on AR solution without neutralizing excess nitric acid.