copper sulphate Questions: freezing, density, color, other properties

A. Hi Jon. I don't know what "na 1830" means, but yes, copper sulphate will crystallize, Jon. But it can be remixed when warmer weather arrives -- although you will probably need a powered drum roller device to do it efficiently.

As for where to park your truck, whether indoors or out, make sure it's within some kind of secondary containment dike since this material is a powerful biocide

A. Hello Dan. copper sulphate comes in many forms: pure anhydrous copper sulphate powder, dry hydrated copper sulphate penta-hydrate crystals (bluestone), or liquid copper sulphate(in which case the density would depend on the concentration).

But I suspect you may be thinking about the metallic copper that deposits when you immerse a baser metal into copper sulphate solution. In this case copper (metallic copper) is deposited, not copper sulphate. So the density is the same as any other metallic copper.

Does the copper fall off easily? Well, as long as the base metal is perfectly clean, not really ... but the adhesion isn't equal to electroplated copper.

Sorry, if this wasn't what you were looking for, I probably didn't understand your questions.

A. copper sulphate pentahydrate (the blue crystals) are soluble, Mr. Sambantar. But materials like this sometimes settle very tightly, driving the water out.

Regrettably, I don't quite understand what you are saying, but if it is possible to roll this material in a drum roller or shake it in a paint can shaker it should redissolve.

Q. Dear sir.....

Okay let me lead you step by step regarding the process we proceed in my company. We deal with semiconductor products so the final process of the production is solder dipping where the IC (integrated circuit) leads are dipped in sulfuric acid (25% concentration) to remove foreign material that would have attached to the leads. The leads are made out of copper. So if I'm not mistaken the results of copper being dipped in sulfuric acid would turn to copper sulphate in contents. The situation is that the solution had been left stored in a container which now had hardened in a form of crystal or salt. the problem is that it had been left to be hard for few days and when we try to dissolve it by adding water it is not diluting.it has been few weeks since the hardening process. It is so hard that it can't be penetrated by the knocking process as well ... please advise on other procedures that can be carried out in solving the problem. And also include the reaction factors and the safety steps such as whether it would create deadly fumes to the air or any combustion, etc. Thank you.

A. Actually, sulfuric acid does not dissolve copper, but it will dissolve copper oxides. So, if you dip copper leads which have oxidized, the sulfuric acid will dissolve those copper oxides to become copper sulphate. It is also possible that your sulfuric acid contained hydrogen peroxide, since peroxide is sometimes added to sulfuric acid to make a "bright dip" or etchant for copper, then it will have the oxidizing power to dissolve copper metal.

Nobody can advise the flammability or explosive potential of a solution which they are not sure the contents of, and which is thousands of miles away. But in general, copper sulphate is not flammable and doesn't fume; and if there is no peroxide or other additives it should not be explosive.

It is fairly common for slurries to "harden". The heavy particles settle, and extrude the water out, and then there is no "room" for the water to get back in to dissolve the solution. I've seen this in various aluminate solutions generated by caustic etching of aluminum, and I've seen it in ceramic-precious metal slurries such as used on catalytic converters. If you stop the agitation, you end up with a hardened 'plaster' in the bottom of the vat even if there is plenty of free water above it.

One way to redissolve it is to continuously "wash off" the top layer of crystals. For example, if you had a bottle of this stuff, it will settle into a rock in the bottom of the bottle, but if you flip that bottle up and down, again and again and again, it gradually reforms into a slurry. If you can get the material into paint cans, a can shaker may dissolve it. If you can get it into drums, a rolling device can probably redissolve it.

Maybe the solution can be continuously recycled through a pump to wash the crystals into solution? That is, put a sump pump with a hose attached into the tank and spray the rock-like areas with the hose until they gradually wash into the solution. This approach, however, may be impractical to do in your situation--sorry, I don't know.

Raising the temperature, if possible, will make a great improvement in the solubility of copper sulphate in any case. So, if it suits your conditions, get the free liquid warm to spray on the block of crystal, then either recirculate until the copper sulphate is dissolved.

A. Sounds like a homework assignment, Cat.

What is confusing you? Give us a hint about all the conflicting info you keep reading that is befuddling you, and we'll be happy to sort out what you misunderstood.

Here's what I just did in 4 minutes of research: 2 minutes each in 2 high school chemistry books--

• The first book gave a quick paragraph with the formula, the common name, and four applications.
• The second gave the formula, the common name, and four applications, three of which were the same as the other text.

If you really need help, people are very happy to offer it--but c'mon now, are you serious about your efforts when both high school chemistry books I have produce the answer in under 2 minutes? I am almost positive that the answer is in your chemistry book without any need for further research -- just look in the index for copper sulphate or copper sulphate.

On this site you'll see copper sulphate mentioned constantly as a copper plating solution, and also as a root killer. You'll also see that in the old days it had several medicinal uses, which have been outlawed in the USA by the FDA (either out of genuine concern about its safety or because the FDA has been hopelessly corrupted by big pharma which wants inexpensive traditional medicines out of public reach). Good luck, but remember: chemistry book index, not internet :-)

Hi, Arvindbhai, in addition to sulfuric acid, you either need an oxidizing agent like peroxide to dissolve the copper, or you need to apply electricity to make the copper anodic. But sorry the detailed process to manufacture a chemical for industrial production is just not a reasonable question for an internet forum -- it'll take a book :-)

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Hi Erin. Sulfuric acid plus copper oxide:
H2SO4 +CuO --> H2O + CuSO4br But I'm not sure if that explains it the way you want. Why do you ask? ---- Why do you ask, Sarah?
Please see www.finishing.com/letters/abstract.shtml. We don't want students to just post their homework assignment for someone else to do, and teachers keep begging us to "Just tell the students to do their own homework!" But we can't tell the situation when you post an abstract question. Thanks.

A. Still with us?

Bright Blue crystals not commonly known as a delicacy for human consumption ... can't be good for you!

Download a copy of the health and safety data sheet and take it along with you to the doctor!

copper sulphate is an emetic so if you have inadvertently eaten a significant amount you have probably been sick!

A. Ron, the best way to get your items plated is to send them to a plating shop, where craftsmen who have spent years learning this industrial art can deal with the issues. If you don't want to do that, please start by trying to find in a library, or buying second hand, a book or two about electroplating, preferably from our list of "must-have" electroplating books to help you understand the issues. It's hard to compose and transmit the needed info in a paragraph or two unfortunately.

We have an FAQ on line here that teaches school children how to do simple copper plating. The basic concept is dirt easy. But the issue that many readers don't predict is the quantum jump between a school electroplating experiment (which generates a useless, thin, poorly adherent layer of metal solely to demonstrate a principal) and producing a robust, bright, pore-free, quality electroplated coating. It's like building a clay model of a car for the students, and them then asking you for the key so they can take it out on the Autobahn :-)

This is not about secrets, it's about the fact that there is a lot to it -- from removing the oxide, to activating the solder (which requires hydrofluoric acid, a very scary thing) and copper, to buying proprietary addition agents that will allow bright plating, to providing proper agitation, efficient rinsing, tight temperature control, removal of ppm contaminants, and other issues. Then you've got the copper on it, but the subsequent silver or gold plating may diffuse into (alloy with) the copper -- so you really need to plate a barrier layer of nickel or white bronze after the copper but before the silver or gold. All practical silver plating baths are cyanide-based, which is a terrible poison having no place in a non-industrial environment.

Good luck with your learning, but there is a lot to it -- and the need to use such truly hazardous materials as hydrofluoric acid and sodium cyanide means you really need lab training. Good luck.

A. Hi Mike. Add warm water, stopper the bottle and shake and shake. The crystal will eventually wash into the water because they are water soluble.

Regards,

A. Hi, Bill. This site has 60,000 threads, covering every imaginable finishing topic. Many are about lacquering & clear coating of metal working art. Please try searching for "art clear coat copper" and I think you'll find many helpful replies and threads that are a good foundation to build upon.

This particular thread has diverged into many different topics -- containment of hazardous waste, properties of copper sulphate, school homework assignments, metal solutions turning to plaster, industrial methods for manufacturing copper sulphate, air pollution, human copper poisoning, copper plating of swords, and using copper sulphate as pesticide -- that is has become overlong & confusing, so it might be best to not expand it to cover clearcoating of copper :-)

Regards,

Hi, Dinu. I'm sure your teacher doesn't want you to simply post your homework assignment and have someone else do it for you. But tell us your whole situation, and what specific part of your assignment you are finding difficult to research and we'll try to help. Good luck.

Regards,

Hi, Sebastian. I have certain proprietary knowledge on that subject which I am not at liberty to disclose because I was not involved in its development, but I did see it implemented to generate copper plating solution from copper scrap at an installation I was involved with.

So I cannot personally assist you, but hopefully another reader will.

Regards,

Hi, Pooja. If you can give us your cost for copper ore, copper scrap, sulfuric acid, and electricity then maybe someone who is intimately familiar with the various processes may be able to help. Sebastian's question, above, may be your answer. Still, I wouldn't choose my business plan based on semi-anonymous internet advice. I think in this case a consultant would be worth a lot more than whatever he charged you. Best of luck.

Regards,