Acid digestion: The How, Why, and Benefits

When it comes to recovering precious metals and gemstones in the case of jewelry, acid digestion can separate itself as the best process to refine the most valuable materials known to man.

Let’s take a closer look at this chemical process and how it helps our customers safely reclaim their precious metals and stones.

What’s so special about acid digestion?

The great thing about acid digestion is that it allows us to selectively separate metals by dissolving them at different stages during the refining process, unlike melting, incinerating, or stripping.  It is especially helpful when dealing with multiple layers of metals.  For example, with gold layered upon nickel, acid digestion gives us the capability to retrieve the gold by dissolving the metals layer by layer.

If we use the analogy of a layered cake, think of it in terms of frosting-cake-frosting-cake.  Now, substitute the frosting for gold, and cake for nickel: gold-nickel-gold-nickel.  Acid digestion helps us retrieve multiple layers of gold while dissolving the nickel.  After the digestion process is complete, we can reclaim the precious metals from the acid solution itself.

Yeah, but how does it work?

Our facilities contain unique kettles where we place the items to be treated.  Then it’s time to add the acid solution —this can include a combination of nitric and hydrochloric acids.

Once the digest process is complete, we use proprietary processes to refine each of the precious metals from the acid solution, leaving us with such sought-after metals as gold, silver, platinum, rhodium, and palladium.  For the mere price of the acids, we cost‑effectively reclaim some of the most beautiful and valuable metals on earth.

Going beyond the metals

Apart from precious metals, the acid digestion process also makes it possible to reclaim gemstones.

The liquid does not damage the precious gemstones in the least.  Furthermore, fake stones like cubic zirconia can be damaged during this process, providing an easy way to visually identify them and keep them apart from real diamonds and other authentic gems.

A natural, cost-effective choice

Given all of the above benefits, it’s easy to see the attraction of using acid digestion.  It’s safe, cost-effective, and a proven method for returning valuables back to their owners in pristine condition.

For more information about this fascinating process and how it can help you reclaim your precious metals and gemstones, contact the professionals at Advanced Chemical.

Advanced Chemical Precious Metals Refinery Is Worth Its Weight in Gold

Gold and silver plating companies, electronics manufacturers, and the general public can benefit from Advanced Chemical Company, a leader in precious metals refining and electroplating processes. For more than 40 years, this family owned and operated company has refined gold, silver, platinum, palladium, and rhodium in its 25,000-square-foot, state-of-the-art facility.

In addition to handling most hazardous and non-hazardous precious-metal-bearing material for a wide array of customers, Advanced Chemical is a leading manufacturer of proprietary precious metal electroplating chemistries and other specialty chemistries, with laboratory services that range from assaying to element identification to product support.

High-Grade Melts (Karat, Gold Filled, Sterling)

With an assortment of volume capacity melters (three gas-fired melters: 50 lb., 125 lb., and 700 lb. capacity; and three induction melters: 25 lb., 100 lb., and 175 lb. capacity), Advanced Chemical has the flexibility to handle any melting needs. Samples are taken using the glass rod method or granulated sampling techniques, or by drilling the bars, if necessary. All customer lots can be melted individually and in varying volumes.

Incineration (Jewelry Sweeps Process, Rugs, Filters, Wipes)

Thanks to its modern thermal reduction furnaces, Advanced Chemical processes a wide variety of burnable precious-metal-bearing material. The company has four incinerators (all equipped with after-burners) that are specifically designed to eliminate burn loss and protect valuable materials. It also has a larger unit that can burn 500 pounds of material per hour and house smaller trays to burn smaller-size multiple lots. Once the incineration process begins, the material is reduced to an ash, and then ball milled and screened to separate fines from tails, creating a fine powder that is blended, weighed, and sampled for an accurate assay sample. The tails are then melted and sampled separately.

Multi-Metal Digest or Stone Breakout (Acid Digestion)

When it comes to material plated with multiple layers (such as gold over nickel over a second layer of gold), these materials can be placed into acid digestion kettles.  The acids dissolve all of the layers of metals. The precious metals are then recovered from the acid solution.  This method is also ideal for removing genuine stones in old scrap jewelry.  Not only are the precious metals reclaimed, the genuine stones are left unharmed.  Once they are cleaned and sorted they are shipped back to the customer to be placed into new jewelry.

Cyanide Strip

This method is ideal for gold plated jewelry and industrial scrap with exposed gold and no barrier layers. The process is fast and more cost-effective than melting or using other processes when the gold is encapsulated or hidden under multiple layers. The stripping process involves immersing the scrap into a stripping solution to remove the layer of gold metal. The scrap is then removed from the solution, rinsed thoroughly, and inspected to ensure that all gold has been removed. The remaining solution containing the stripped precious metals is then volumed/weighed in any number of ways that suit the customer’s specific preference and assayed for gold. Our customers are also paid on the base metal content.

Four In-House Labs (Fire Assay)

Simply put, assaying is the process used to determine the composition of a substance, which determines a material’s value. With four in-house labs, Advanced Chemical can perform, Fire Assays, inductively coupled plasma (ICP) and x-ray fluorescence assays, as well as metallurgical assays for valuing gold and silver, gravimetric analysis for measuring mass, and atomic absorption spectroscopy, which involves atomizing samples before studying their absorption of light.

10-Oz. Silver Bars

Because people are always looking for affordable and stable investment opportunities, Advanced Chemical offers 10-oz. silver bars, which, unlike gold, provide a larger investment return. Minted for such investment purposes, these bars also attract collectors, since they come with a certificate of authenticity and unique serialized number. The silver bars are also an ideal gift for special occasions as they are presented in a beautiful black velvet bag.

Whatever your precious metals, refining, or electroplating needs, Advanced Chemical Company has the expertise and equipment to serve you. Its 25,000-square-foot, ISO-9001:2008, ISO-14001:2004, OHSAS 18001, R2:2008 Certified & ITAR Registered full-service precious metals refinery, headquartered in Warwick, Rhode Island, provides state-of-the-art and environmentally safe refinery methods for gold, silver, platinum, palladium, and rhodium. To have Advanced Chemical assist you with your refining needs, visit

Advanced Chemical Joins Industry Movers and Shakers at E-Scrap 2014

On the heels of hosting the John Venditti Memorial Golf Tournament, Advanced Chemical swings into more action as we prepare to attend and exhibit at the annual E-Scrap Conference & Tradeshow in Orlando, Florida.

E-Scrap is the biggest electronics recycling conference in North America and for two days (October 22-23), we’ll network with fellow industry leaders and keep updated on e-scrap collection issues and the latest advances in R2 and RIOS.

Since 2003, the annual E-Scrap Conference & Tradeshow has attracted newcomers and veterans in the electronics recycling industry. The conference provides educational sessions that help us remain a leader in the industry, including, “The State of CRT Recycling in the U.S.,” “Policies and Programs from Around the World,” and “How Shifts in Product Design Affect Recyclers and Refurbishers.” In addition to taking advantage of these learning opportunities, the event also focuses on recycling market factors, growing your business with e-Stewards certification, and maximizing value in reuse, as well as supplying an overview of e-scrap laws and legislative and policy considerations.

As a leading manufacturer of proprietary precious metal electroplating chemistries, other specialty chemistries, assaying and element identification, we understand the importance of staying current on what is happening in the industry and are looking forward to this great opportunity. We will also be at booth 515 at the 2014 conference, so if you’re planning on attending the event, please stop by and say hello!

Advanced Chemical is a family-owned and operated full-service precious metals refinery, headquartered in Warwick, Rhode Island. We are ISO-9001:2008, ISO-14001:2004, OHSAS 18001, R2:2008 Certified and ITAR Registered and refine gold, silver, platinum, palladium, and rhodium. Contact us today for more information about how you can benefit from our years of experience. We look forward to earning your business.

A Refined Process

When you get down to the nuts and bolts of Precious Metal refining, the sample is the end all be all.  It is the deciding factor as to how much our customer will get paid.  So it goes without saying, the sample is extremely important.  As the leading company in New England that does this kind of work, we go through several steps to ensure we obtain the perfect homogenous sample. The place this happens is in our Sample Room.

The isolated temperature and humidity-controlled environment in our proprietary sample room is ideal for determining the exact value of all the metals a customer brings in. As a Precious Metals refinery, we get quite a variety of material, things like; hazardous solutions from platers, chamber scrapings from Hi tech processes, and Polishing Sweeps from jewelry manufacturers. These metals may come to us in a bag or buried deep in an old rug from a jewelry repair shop. You may wonder how we are able to pay a customer for the precious metal particles embedded in that an old rug. Sure, the customer could vacuum the rug, send us the bag, and receive a check for the effort in which case they’ll, A) get a smaller check than they should, and; B) throw away many dollars worth of precious metal particles.  The other option is they can bring the rug to us at Advanced Chemical where we incinerate the old floor covering and use a series of processes to secure a sample that our lab can assay. (Check out the technique.)

Our sample room is home to two sample blenders, two spinning rifflers, as well as dust control equipment. This process makes Advanced Chemical far more cutting-edge than other operators still using the Byzantine “paper folding” technique where the dust from incineration is blended by hand with the dust being placed on a piece of paper.  The paper is then folded a number of times in order to blend the dust and samples are then scooped out of the dust. Our process of using the blenders and spinning riffler gives us the greatest improvement in homogeneity and sample integrity. Years of perfecting our technique and increasing our capacity have coincided with our ability to deliver to you that ideal, homogenous sample for which you’ll get paid.

No matter how big or small, every job that comes through our facility is treated with the same attention to detail. After all, you want to get as much as you possibly can for your precious metal particles… and we want you to as well.

Advanced Chemical is a family-owned and operated full-service precious metals refinery, headquartered in Warwick, Rhode Island. We are ISO-9001:2008, ISO-14001:2004, R2:2008 Certified and ITAR Registered. Contact us today for more information about how you can benefit from our years of experience and our open door policy. We look forward to earning your business.

Refining Precious Metals to Gain the Highest Value – Part Two: Smaller Orders

In the first part of this series, we discussed the steps of precious metal refining for industrial-materials and the varying amounts of time it can take to return value to you, the customer. Every month, our team transports precious metal bearing hazardous waste materials from all 50 states.  Those materials arrive at our main facility and are then weighed, assigned a lot number and secured.  This entire process is recorded via video surveillance for added security.

These materials are then processed into a homogenous form through one of several methods.  Once a homogenous form is achieved, samples are taken and assayed to determine the amount and quality of the precious metals contained within the material.  With these types of materials, the entire process can take up to 60 days.  This might seem like a long time, but it allows us the opportunity to ensure the most value for our customers.

Less Complexity, Quicker Turnaround

For some of our customers, however, the intricate processes that go along with hazardous materials such as electroplating solutions, filters, rugs, and tons of circuit boards really aren’t necessary.  We often deal with karat jewelry, dental crowns, and various types of metals including gold, silver, platinum, and palladium.  In these cases, melting can still be an option and a small amount can settle in as little as three working days.  But there are many types of precious metal-bearing materials that do not lend themselves to melting.  For these materials, the various processes we offer can take 20, 30 or up to forty-five working days.

Cyanide Strip

In instances where material is electroplated with gold, the cyanide stripping process is a fast, efficient, cost-effective way of refining.

By immersing the scrap we receive into a stripping solution, we can remove the gold and then assay the solution to determine the ultimate value.  This process is so efficient, we can strip up to 10,000 pounds of plated material in a single day.

Acid Digestion

For material plated with multiple layers, for instance – gold over nickel over a second layer of gold – the cyanide strip method will not get through the layer of nickel.  These materials can be placed  into our acid digestion kettles where we can reveal all of the layers of precious metals.  This method is perfect for removing genuine stones in old scrap jewelry.

Show Me the Money!

Once the refining process is complete, the resulting material has been weighed and the value of the precious metal is determined, there are several methods which we use to return that value to the customer:

  •  Check
  •  Wire transfer
  •  Metal transfer to a customer’s supplier
  •  Products provided by Advanced Chemical such as gold grain or Potassium gold cyanide
  •  Plating baths
  •  Resins

Regardless of which refining method you choose, we guarantee the highest level of security, the quickest turnaround time possible and the most value for your precious metals.  Give us a call today to find out which process will best suit your needs.

Precious Metal Refining, Part One – The Steps (and Time) Needed For Value

When you hear the term “precious metal refining”, you might think about the simple process of superheating a substance, melting away non-precious metals and impurities, and leaving behind a valuable substance.  That’s certainly an aspect of what we do here at Advanced Chemical Company, but there’s so much more involved in our processes.  For over forty years, we’ve been dealing with hazardous materials that bear precious metals and have since become the largest hazardous material refiner in North America.  Because of this, precious metal refining can be as simple as a three-day process… or, it can become an involved 60 day procedure.

In this first of a two-part series, we’ll take a look at the lengthier aspects of precious metal refining.  In part two, we’ll highlight some of the simpler approaches to the process.

The More Complicated the Job, the More Time it Takes to Refine

A large portion of our business is Industrial Refining.  Several times a month we receive precious metal bearing hazardous waste from all 50 states.  When the materials arrive (securely contained), they are weighed, assigned a lot number and secured.  And talk about added security – extremely high value material can be weighed on a scale which is connected to security camera,   recording the entire process.

When refining, our goal is to obtain a homogenous sample and perform an assay to accurately determine the precious metal content.  An assay is a qualitative or quantitative analysis of a metal or ore to determine its components.

As you might expect, different materials require different sampling techniques, for instance; Materials in cyanide solution are pumped into our sampling tanks.  The drums are triple rinsed and added to the solution.  The solution is then heated to 120 degrees and agitated constantly.  Solution samples are taken from five quadrants in the tank, each corner and the center.  The weight of the solution is then verified and the material is ready for assaying.

Materials in acid solution require a different refining process.  Incineration of these materials takes place in one of our six furnaces and treated as a “sweep”.  At the end of the process we are left with a fine powder that is blended/mixed and sampled.

Acid digestion is yet another involved process here at Advanced Chemical and we’ve detailed that in a past article.

A Pin sample is taken when melting is required.    A specialized glass vacuum rod takes the molten metal from the center of the melt.  When the samples cool it resembles a pin. In all of these processes we can provide up to three samples:  one for our laboratory to assay, one for the customer upon request and a third sample sent to an independent lab in the event of a discrepancy.  The third sample is commonly referred to as the “umpire” sample.

Worth the Weight…and the Wait

The assay performed determines the quantity of the precious materials found as a percentage by weight.  That percent by weight is then multiplied by the after melt weight of the bar of material that results from the melting process.  After the assay is complete, the customer will then have a clear idea of the amount of precious metals available to them.

As you can see, we have quite a few involved, proprietary refining processes.  Of course, our attention to security, detail, and providing the most value to our customers is what makes us the industry leader.  If you have precious metals that need to be refined, call one of our experts to find out what process will best match your needs.

In our next article, we’ll discuss some of the simpler approaches of refining smaller orders.