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Determination of the concentration of gold solution





Q. I am trying to source the gravimetric procedure for the analysis of gold of a plating bath. Do you know where I could find it? Thank you.

Maria Quintana
- Coventry [England]
July 13, 2021



"Gold Plating Technology"
by Reid & Goldie

on AbeBooks

or eBay or

Amazon

(affil links)

A. Hi Maria. Reid & Goldie has a 25-page chapter on Analysis, including gravimetric methods. Unfortunately, I can't tell you where you can source an affordable copy of this increasingly hard to find book :-(
But according to worldcat.org, the University of Birmingham, which they claim is 18 miles from Coventry, has a copy :-)

Luck & Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
July 2021

thumbs up sign Thank you so much for your help Ted

Maria Quintana [returning]
- Coventry [England]
July 14, 2021


A. Hi Maria
Nearer to you then Birmingham is PMD Chemicals, a major supplier of plating solutions who have their main office in Coventry.
Gravimetric gold is not quite as simple as the books suggest and it helps to see a demo. If you contact PMD and ask nicely you might be invited to the lab or even get a visit from their technical rep.

geoff smith
Geoff Smith
Hampshire, England
July 24, 2021


thumbs up sign Thank you, I will contact them :)

Maria Quintana [returning]
- Coventry
August 18, 2021


A. Hi,
There are approx. 8 to 9 methods of gold assay: volumetic, gravimetric, fire assay, by potassium iodide, XRF, and so many.
I suggest you put an ash-less filter paper in plating bath, burn it; you will get the residue, purify it again, and check the assay.

bhupesh mulik
refining consultant - Mumbai, India
August 28, 2021




⇩ Closely related postings, oldest first ⇩



2002

Hello,

Q. I am trying to determine the concentration of a gold solution. I had prepared a colloid gold solution by reaction with HAuCl4 and a sodium citrate solution. I had filtered the solution through a 0.45-micrometer membrane filter. And I would like to know how determinate the concentration in gold of my solution. If anyone can help me!

Thanks!

Corinne Martineau
- Netherlands


A. Most people would use atomic absorption spectroscopy [on eBay or Amazon].

James Totter
James Totter, CEF
- Tallahassee, Florida
2002



A. Corrine,
If you don't have access to an AA, there are a couple of other methods you could try. If your company uses an x-ray fluorescence spectroscope to measure thicknesses, you can install software in it which will quantitatively analyze gold ion in plating baths. It's a fairly simple procedure, but standardizing is tedious. Also, if you don't calibrate it on a regular basis, your results will be about as accurate as a scud missile.
Gravimetric analysis is another option. By reacting a 5 or 10 mL sample of your solution with sulfuric and nitric acids, with heat, followed by complete reduction using hydrogen peroxide, you can extract gold metal which may be weighed on an analytical balance. That procedure is widely known and available.
Best bet? James was right. Atomic Absorption.

randy fowler
Randall Fowler - Fowler Industrial Plating, LLC
Cleveland, Tennessee, USA
2002



Q. Have our ore in anaq solution, chlorine and 6M HCl, orp 720-920, pH .5-1.5. Maintain below boiling until the complex or with basic SiO2 background. once we know we have concentrated solution we pour through a ionic selective collector called analogin. We then strip the analigs. I need a short inexpensive ionic test strip to know when the solution is loaded before pouring through the analigs. Can you help me?

Mark Bateman
- Magna, Utah, USA
2007




Q. How to determine gold in gold plating solution?

Huong Pham
- Vietnam
April 21, 2012



A. By what ever means that is recommended by the mfgr. of the solution or the salts.

Barring that, get an analysis book and find a method that will work for your particular alloy (hopefully in your budget also). The best methods are expensive.

James Watts
- Navarre, Florida
April 26, 2012



May 2, 2012

A. I used to do this: I had a piece of platinum clad titanium gauze, about 15 cm2. I'd take a bath sample, add a gram of sodium cyanide, dilute to a suitable volume, and make it the cathode in a little plating cell I made out of a cut down plastic bottle. I used a little piece of 12 mm stainless rod as the anode. Apply current for about 40 minutes, with stirring.

Weigh before and after.

dave wichern
Dave Wichern
Consultant - The Bronx, New York



[on eBay or Amazon]?

Huong Pham [returning]
- Vietnam
May 8, 2012



May 9, 2012

A. Dilute 1.00 ml solution to 100 ml with distilled water.

Digest 10.00 ml of this solution (in a fume hood) with 5 ml aqua regia. Hydrogen cyanide will be evolved. Warm gently until all solids dissolve.

Transfer quantitatively to a 100 ml volumetric flask [100 mL flasks on eBay or Amazon] and dilute to volume. If your bath Au concentration was 5 g/l you'll get 5.00 mg/l in your sample prep. This ought to be within the linear working range for Au. You may have to dilute the sample prep. a little more.

Evaluate concentration by comparing to s standard curve made with distilled water and at least three Au standards.

dave wichern
Dave Wichern
Consultant - The Bronx, New York




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