There is nothing wrong with your salt. What happens is salt is naturaly a brown color after it is mined then they normally wash it then it becomes white. The whiter the color the more it is cleaned. As far as I know that is what I have been told. I questioned the same thing when we got a load of salt delivered last year.
If you are on the East Coast chances are that the Rock Salt was imported from Europe. Some of the European Salt deposits are higher in Clay or Iron, hence darkening the salt crystal intrinsically dark red or brown. Sometimes the sodium choloride content is reduced, but the performance is not noticible. It has been noted that the naturally occuring brown salt from Europe tends to have a harder crystal. The result of this allows the crystal to stay around longer. Salt producers typically only wash Solar Salt in order to remove magnesium and calcium sulfate. Solar Salt is produced by the evaporation of H2O leaving the solar salt behind.
Solar Salt ponds are common in high temperature low rain areas, New Mexico, Southern California, The Mexican Peninsula area and the Carribean. You may want to ask your supplier for an MSDS sheet if you want to find out exaclty the root point of origin.
Environmental Surface Treatments
I have never seen bulk white salt, just the bagged stuff is white. Most people assume we are putting down sand or mix, it's so brown. What I had heard is that the "brown" salt is not coming from CONUSA mines, but rather from Carribean mines or methods. Being close to the Newark harbors, I was tolds its just as easy for them to get it from the Carribean on barges as from US mines. This makes it look different because of the region it comes from maybe, for what ever the real reason? Stuff works great (better than the bagged, washed, perfect looking white stuff in the bags) so I've never had a problem with it. I believe our bulk is coming from International Salt also.
We had some of that blue salt in a load this year. I forget why (Chuck Smith!) but that's supposed to be really good stuff (works faster & to lower temps). It worked & spread really well.
Yes, as Doug said, the blue is an anti-caking agent. Possibly Sodium Ferrocyanide? It does help it spread better. I don't think it has any affect on the melting ability, though it might. Our first loads this year came from Cargill, and it was white and dry. After that, all our loads have come from International Salt. It is the brownish color. When it's dry, it looks white, but as soon as it gets a little wet, you can really see the brown in it. One load from Cargill had a lot of green in it. I am told this is due to a copper vein running through the salt deposit.
Jay, maybe you can tell me what Sodium Ferocyanide is used for? It is listed on the MSDS sheet I got from International Salt. Sounds like some nasty stuff. The MSDS was a faxed copy, so it wasn't very clear.
The salt I have been selling this year comes from Port Newark, (not international though), and has an anti caking compound in it, but it is white/tan in color. Its been great so far this season, had not 1 complaint about it at all, AND one customer leaves it out side uncovered ( which is nuts) and still has no problem with caking or hardening!!! I guess color doesn't really matter in this one.
THE BROWN COLOR DEPENDS WHERE THE SALT COMES FROM. IT IS MY UNDERSTANDING FROM WHAT I HEARD FROM A GUY WHO OWNED SOME MINES IN JAMAICA THAT THEIR MINES WERE BROWN. OTHERS IN THE DOMINICAN REP. WERE WHITE.
Sodium Ferrocyanide is added to rock salt as an anti-caking agent.
It is also known as YPS, Yellow Prussiate of Soda. It is added to rock salt at a rate of approixmately 80 pounds to 1000 tons of rock salt. It is added strictly for flowability and has no melting capability, therefore it is not added for anything to do with melting power.
Over the years I have answered many questions from contractors and consumers because of the word, "cyanide", in Sodium Ferrocyanide. When added at the right dosage level, this is a non issue. Domestic Salt companies add YPS as it is being conveyored out of the mine. Some times imported rock salt has YPS added directly to the hold as it is being stevedored off.
The next time your in a restaurant take a look at one of those little salt packages and YPS will most likely be listed as an ingredient on the packet. Even some of the salt round packages sold in grocery stores contain YPS. All of this is FDA approved.
QUESTION: What additives are used in deicing salt and are they harmful to humans?
ANSWER: The only additive currently added to deicing salt is anticaking agents, either ferric ferrocyanide (Prussian Blue) or sodium ferrocyanide (Yellow Prussiate of soda). Both additives are non-toxic and harmless to humans. The Federal Food and Drug Administration allows the use of YPS anticaking agents in food grade salt.