FMF - Friends of Minerals Forum, discussion and message board

[John Betts]

I routinely wash my minerals in Cascade brand dish-washing detergent.

Recently I noticed that anglesite specimens turn cloudy after a brief soak in diluted Cascade/water solution. The cloudiness appears to be on the surface and it is not a reaction to temperature as the cleaning solution was equal to ambient air temperature.

Attached is an image of the label on Cascade that mentions it contains sodium silicate, sodium carbonate and enzymes.

Does anybody know what the reaction is between these ingredients and anglesite?

More importantly, any suggestions on reversing the reaction?

Thanks,
John Betts

[alfredo]

It might be forming a thin layer of lead carbonate (cerussite) on the surface, in which case it could be removed with hot HCl. But since the surface was altered, it is unlikely that the original luster of the anglesite would return. Might be worth a try anyway.

[lluis]

Good morning.

I agree with Alfredo that cloudiness is a surface alteration, but in this case, containing detergent carbonate and silicate, I am pretty sure than layer is a lead silicate.
Diluted clorhidric acid I fear that would do nothing good (lead chloride is insoluble at room temperature, and I doubt that chlorhidric acid affect a lot a lead silicate).

For minerals, I would suggest always to use a non-ionic, not build up, pH 7 detergent.
Just to avoid surprises in the cleaning

With best wishes

Lluís

[Jordi Fabre]

John,

I'm afraid you can't do nothing else. The Anglesite is an extremely sensitive species and it loose its luster very quick, sometimes just with regular water if it is non ionic and after long time immersions (over one-two hours...)

[John Betts]

Thank you for confirming what I suspected. I will be more careful in the future.
(This message board is the best! I could not get my question answered anywhere else in such a short time.)

[Pete Modreski]

I learned a bit from this (aside from about how not to clean anglesite), because I was totally unfamiliar with "non ionic detergents". But I did a little googling about it, and now I know a little more!

[alfredo]

Anglesite is remarkably resistant to acids, even strong ones, but surprisingly it will dissolve in some non-acidic water solutions of salts like ammonium citrate or ammonium acetate. If the cleaners contain ammonia it is possible that the surface is just frosted by etching?

[Mark Ost]

That was my understanding of anglesite also. I just finished reading a paper that stated that anglesite, in effect, protected the galena from further alteration. Of course this is in a natural setting without whatever is in cascade.

[lluis]

Good afternoon, Alfredo, Mark, List

For solubility of anglesite in what you say non-acidic solutions, I would suggest that ammonium citrate and ammonium acetate solutions are basic. Lead could form plumbates in presence of excess hydroxide ions, and well, if hydroxide ions are there, and oxygen is there, well, some plumbate could be formed. That will produce a slight etching of crystal and the subsequent frosting. Ammonia also produces a basic solution, so would do same.
Not from complexation (complexation would mainly be done by halogenides), but enough to get crystals frosted.

Mark, when galena is oxidized to anglesite, the anglesite protects (at least partially) galena from humidity and oxygen, so, at least transformation to anglesite is retarded.
If you place anglesite in a solution with carbonate and silicate, you place it in a place where plenty of water is able to react, where a lot of hydroxide ions are, and where a lot of carbonate and, worst, silicate ions are: you get lead silicate very quick...

With best wishes

Lluís

[lluis]

Hi, Pete, Listizens

Sorry for using chemistry names....
I should have placed a google link to explain....
My fault! The chemist in me... :-)

Anyway, cleaning minerals is all but not exactly easy. And with the possibility to get a cleaned piece that is uglier than the uncleaned.... :-(

With best wishes

Lluís

[Tom Tucker]

As for the "Contents" of the dishwasher deteregent, I believe that kind of listing includes only those ingredients which are required to be noted if they are included on a government (FDA, etc. ???) tabulation. If an ingredient is not included in the government list, it does not have to be noted. Thus, there can be plenty of ingredients in the detergent that we are not informed of, causing further unanticipated reactions. Tom

[lluis]

Hi, Tom

Well, for what I know from Europe, using REACH you should only list ingredients that are considered hazardous by this rule, and only those are listed. That for industrial products.

But for home used ones, at least in Spain (and I do not think it is the more strict country), I am pretty sure that all ingredients should be listed. And, at least some years before, they should be listed in order of concentration: first the most abundants and following the lesser ones. Then salt is listed (and is not considered hazardous...Even appreciated in cooking... :-) )

But if a thing declares things that are considered dangerous for a type of mineral (e.g.: acetic acid and is intended to clean a carbonate; or a sequestering agent and is used to clean same..., or ammonia for cleaning a iodargirite, or boleite.), better do not use it.


Hope it serves

With best wishes

Lluís

[Matt_Zukowski]

In the US, most commercial products like this have a MSDS, or a material safety data sheet, that lists all sorts of information including composition, bulk properties, etc. In terms of composition, all hazardous components in excess of 1% must be listed (0.1% for carcinogens), and although they do not have to specify the exact percentage of every component in the mixture, they do have to specify the composition information in terms of a range. Sometimes the manufacturer can get away with not listing certain components on their public MSDS if the component is proprietary. In terms of bulk properties, many are usually listed on MSDS.

If you google "MSDS cascade dishwasher detergent sodium silicate, sodium carbonate and enzymes" you get a number of hits, and it seems that this cleaner forms a basic solution with a pH from 9.5 to 11, depending upon the formulation. This type of cleaner is in the class called alkaline detergents, and they can be quite reactive.