New "acid" to remove calcite from specimens

I have been cleaning some specimens collected this winter - most are either scarn minerals in vugs that are filled with calcite, or magnetite, sphene, apatite, etc covered by calcite. The scarn minerals are usually not affected by hydrochloric or other acids that will remove calcite, but the minerals in the magnetite are - hydrochloric frequrently turns the apatites and scapolites to piles of "sand".

Looking for other ways to remove calcite and save the minerals, I have found a new "synthetic acid" that works great! The material is called EMS Barracuda Concrete Stripper, and is manufactured by Environmental Manufacturing Solutions. The material is very safe to handle, and the MSDS sheet lists it as 000 (non reactive, non corrosive, non flammable).

The material is an amber liquid, and has a slight "soapy" smell, but no fumes of any kind. It is safe on all metal I have tried it on, all clothes I have tried it on, and on counters, floors, etc. (tile grout would be affected though as it is basically calcite with sand). It is safe to handle - the only thing I noticed was a scratch I had from a rose bush stung slightly when my arm was in the liquid. As with all liquids and chemicals, I wear goggles, and if you were inclined to drink the stuff for some reason, the MSDS says that it may cause "loose bowels".

The barracuda dissolves more calcite per gallon than hydrochloric (but slower), and is much safer than any other way I have found to remove calcite chemically. When dissolving the calcite, it causes a very fine "foam" on the calcite as it dissolves. Like dish detergent, it causes a "foam cap", so you have to be careful to leave enough room in the bucket above the liquid level (it did clean all the dirt off my floor in the laundry room real good!). No fumes, no worrys about burns, etc. It did still affect the apatite and scapolite, but mostly just the luster - it did not turn them to "sand" like other acids have.

Unfortunately, the material did not do squat on removal of iron staining on any of the specimens I tried it on, so I am stuck with more aggresive chemicals for that.

I found the barracuda at a local concrete supply store - he had it in 250 gallon totes, but allowed me to buy 5 gallons at a time - cost was only slightly higher than hydrochloric adic would have been.

Hi,
i've personally found that a good automotive rust remover will get rid iron staining, but don't use it on soft minerals like malachite or azurite.

Rory,

Thanks for the information!!

Philippe.

I have never use acid to remove minerals from minerals, so I have a silly question, something I hav´nt seen on this site yet. Do you have a before and after picture of the acid bath pieces. I'd like to see how much calcite is removed from a piece and what it looks like "cleaned".

Generally, the calcite to be removed is a main mineral in the vein, and is late-stage. It covers/surrounds all minerals that were formed before it - these that we want to expose. Take for example, [www.mindat.org] . Before acid, it was just anhedral white calcite on matrix, with crystals only visible on edges. Now the calcite is removed and it is much more interesting!

Also another example is [www.mindat.org] and [www.mindat.org]
These were on the same specimen, a large ~40 cm piece of host rock with much calcite. After HCl, I got about 5 specimens and the rest had nothing good. Before HCl, simply a big piece of calcite+rock with a bit of schorl, pyrite.

So I don't have before-after photos, but you can imagine how much calcite is removed - anywhere from 2 cm thick to 20 cm + Just depends on the vein size and how much calcite was kept on the specimen when it was removed.

Philippe.

I have used ordinary pickling vinegar to disslove calcite with good results. It is slow and relatively expensive but it does work. I cannot speak on its effect on scapolite or apatite, but it doesn't bother the other skarn minerals (garnet, epidote, diopside,magnetite,cobaltite....).Best of all it is readily available at almost any grocery store. I will definetly check out Barracuda,though.


Gord

The EMS Barracuda Concrete Stripper sounds very useful, but my experience as an industrial chemist and hazardous material technician has made me skeptical of product claims. The term "synthetic acid" sounds like it was written by an advertising agency. All materials can be either "natural" or "synthetic." The actual active ingredients are non-disclosed on the MSDS as a patented product and no really useful information is present as to what it is and how it works. History is full of examples of materials that were once thought to be harmless, but later were found to have insidious hazards. Having said that, anything that is more effective and less hazardous than hydrochloric acid is bound to be useful. The fact that this product is being marketed to remove concrete build-up on concrete trucks is significant. I intend to try it, but using precautions that should be used with any active chemical

Avoid skin contact.
Use in a well ventilated area.
Try a small sample or hidden corner for possible unintended effects before treating a valuable specimen.

Mark

Chemically "synthetic acid" doesn't make sense. Whether HCl, for example, is created by man or nature, it will have the same effect. Same with Sulfuric acid. Its just not making sense.

I looked up the MSDS on this product, and the composition is blocked as being a trade secret. It does appear to be organic based from the cited specifications. I normally use acetic acid to dissolve calcite so I can save things like apatite. Would be interesting to test this versus HOAC.

Henry Barwood

Is there a place to obtain this cleaner here in the US?

Henry Barwood
Troy University
Troy, Alabama USA

Don't know if they take a drum and break it down or if it is packaged by the pail.
They sell this stuff by 5 gallons:
[orders.jpsupply.com]

Also [www.enviromfg.com] has dealer lists for this.

David,

Thanks for the information. I may have to accumulate a few specimens to warrant even a 5 Gal. pail.

Henry Barwood
Troy University
Troy, Alabama USA

You might want to call up their tech support line. You might be able to finagle some samples for testing purposes.

what is the definition of "Scarn" please?

A skarn is a contact metamorphic rock developed when magma intrudes a dirty limestone (typically). Minerals such as grossular, epidote, wollastonite etc. are formed by the heat and fluids from the magma.

Hello,,Found a product in Australia that sounds similar to your Barracuda Concrete Cleaner only it was callel Barrell Clean Safe(as in concrete truck barrel cleaner) .Of course it came with the msds data etc but with secret ingredients etc..I suspect it is the same product but packaged and named differently..It was a light yellow color,no smell,similar to the description of Barracuda..I tried it on a specimen that i usually use acetic acid on..It ripped the calcite off quickly ,damaged the apatite but left monazite in good condition..I will stick to acetic from now on as a lot of our material in calcite can have Apatite,Garnet,etc Con



Edited 1 time(s). Last edit at 07/20/2009 01:54AM by Costas Constantinides.

Probably a poly(ethylene imine) derivative.

Hi Jamison, hi All,

to remove Calcite I use Essigessenz = pure acetic acid, which you can buy in Germany in each supermarket in the "Spice" department (besides vine gear, olive oil, salt e.c.t.)

It is easy to handle, not very dangerous - don´t bring it in Your eyes! It is an acid!

And the generated Calcium-Acetate is soluble in water. You wash after cleaning Your spezimen in pure water and the acid and the Ca-Acetate is away.. Minerals like Apatite or Fluorite are not attacked, if You don´t let Your spezimen stay a long time in the acid.

I let normaly a small rest of the calcite on the spezimen, so You can see: Calcite was removed by acid.

Other carbonate minerals like Malachite, Dolomite and others are attacked or not, so You have no clear result. Normaly the are not totaly removed, but damaged.

Aragonite reacts with acetic acid like Calcite.

My Pyrochlore of the Kaiserstuhl (...photo-39996.html) was liberated from Calcite by acetic acid. Below the Pyrochlore You can see, unfortunately not sharp - an Apatite prism.

Greetings from Goslar

Georg

Hi Jamison, hi All,

little bit more precise: Essigessenz is pur, 25%, acetig acid.

Greetings from Goslar

Georg

Hi,

It seems that the "synthetic acid" is urea hydrochloride, as disclosed in a patent-infringement lawsuit filed by Peach State Labs against Environmental Manufacturing Systems.

(US District Court for the Northern District of Georgia, Rome Division; Filed Nov 26, 2008)

The disputed US patent is 5,672,279; "Method for Using Urea Hydrochloride".

The patent is fairly straightforward (for patents, that is) in describing how to prepare and use urea hydrochloride for the removal of calcium carbonate.

Ed