Cyanide safety

[g_axelsson]

Hi guys, before posting this publicly could you check this post for errors, omissions or general improvements. I tried to do some research but I'm lacking practical experience... and as you all know, English isn't my first language. This isn't a post I would like to have errors.

On to the post...

The meaning with this post is to create a reference worthy to be included in the library. Any off topic remarks will be moved or removed and this first post will be edited for any omissions, errors or better explanations. If commenting on a specific part, make a quote as the original part might be edited.

Cyanide safety, part one of the cyanide posts for the library.

Cyanide safety is extremely important, if cyanide gets into the body it will bind to the red blood cells and stop the uptake of oxygen just as carbon monoxide does. It will choke you to death.

Cyanide poisoning
Cyanide is highly toxic. If mixed with acid the extremely poisonous hydrogen cyanide gas is produced.
The pH of cyanide leach should never go below 11 to keep a safety margin against creating HCN!

Low level exposure
Some people have an increased sensitivity to cyanide and develops rashes if it get on the skin or from working in the fumes from a heated cyanide bath. Sometimes even turning into small blisters. It can take up to a couple of days for the rash and blisters to disappear.

Mild poisoning
The onset of symptoms after exposure is very rapid. Symptoms of mild cyanide poisoning include
headaches, giddiness, nausea, (and vomiting if cyanide has been ingested). The person has
difficulty breathing, a sense of suffocation and a feeling of general weakness with heaviness of
arms and legs. Cyanide also causes irritation of the nose, mouth, and throat.

Severe poisoning
Severe cyanide poisoning may be characterized by vomiting, gasping for breath and loss of
consciousness. After loss of consciousness, breathing may be weak or absent and may result in
cardiac arrest and possible death.

Chronic poisoning
The symptoms of chronic cyanide poisoning are similar to those of mild cyanide poisoning. These
include headaches, dizziness, nausea or vomiting, and visual and peripheral nervous system
effects. Repeated or prolonged skin contact to low concentrations of potassium cyanide dust may
lead to dermatitic effects (“cyanide rash”) characterized by itching and skin eruptions.

First aid treatment
- Immediately move the patient to fresh air and remove any contaminated clothing.
- Call for help.
- If the patient isn't breathing, do not use mouth to mouth method because of the dangers of cyanide contamination around the mouth. Use a resuscitation bag and mask instead. Give 100% oxygen by mask.
- If the patient is lacking a pulse, start cardiac massage.
- Move the patient to a hospital as soon as possible.

Precautions
All personnel should be trained in hazards with cyanide, recognition of symptoms and first aid treatment of cyanide poisoning.

Keep oxygen and a resuscitation bag and mask on site with the first aid kit.

The local hospital should be informed that cyanide is used at the workplace and that there are a possibility that people can be suffering from cyanide poisoning.

Storage
Cyanide should be stored in a cool, dry and well ventilated place. All containers should be clearly labelled and stored off floor. Any local laws should be followed.
Cyanide should always be stored separate from acids and catch basins should be constructed so that spills of cyanide will be separated from spills of acid.
The cyanide storage should be lockable and the access should be limited to as few persons as practical.
Eating, drinking and smoking should not be permitted in the vicinity of cyanide.

Handling
Before moving or handling containers with cyanide, check the lid and container for leaks. If damaged, move the content to a clean new container and mark it clearly that it contains cyanide.

Any container or tanks containing cyanide should be clearly marked.

References
* GRF : http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=24567&p=259896#p259896 GSP on safety rules when working with cyanide
* Wikipedia : https://en.wikipedia.org/wiki/Cyanide_poisoning Cyanide poisoning
* Worksafe New Zealand : http://www.worksafe.govt.nz/worksafe/information-guidance/all-guidance-items/chemicals-in-electroplating-and-related-industries/chemicals-in-electroplating-and-related-industries-208-kb-pdf Safety sheet for electroplating industry

This article can also be found at http://goldrefiningwiki.com/mediawiki/index.php/Cyanide_safety

 

[FrugalRefiner]

Severe poisoning'
Severe cyanide poisoning may be characterized by vomiting, gasping for breath and loss of
consciousness. After loss of consciousness, breathing may be weak or absent and may result in
cardiac arrest and possible death.

Göran, thanks for starting this thread. I didn't want to edit you post, but there is an unnecessary apostrophe after the word poisoning.

Dave

 

[g_axelsson]

Feel free to edit if you like, just add a comment about it. The apostrophe was a remnant from the wiki markup where three apostrophes on each side creates bold text.

... thinking about it, there shouldn't have been one there and it wasn't any on the wiki, I just goofed up.

If I have time I'll create some more drafts here for the other cyanide discussion threads.

Göran

 

[FrugalRefiner]

I have a couple of suggestions for the Precautions section.

Never process cyanide in the same building where acids are used or have been used.

If you plan to work with cyanide, a cyanide antidote kit must be kept on hand.

Never work alone. Always have a second person nearby, but not in the processing area. This person should be able to recognize the symptoms of cyanide poisoning, be capable of removing the person from the processing area, and administering the antidote kit if necessary.

I know these may be considered "overkill" (pun intended), and experienced refiners may be able to bend the rules, but if we're going to present this information I think we should advise extreme precautions knowing that many members will try shortcuts. I don't expect that those experimenting with eco-goldex are actually going to buy an antidote kit, resuscitation bag, or oxygen, but if we stress these as "must haves", it might keep a few from actually trying it.

I hope Chris and Rick will get involved here. It would be nice if we could also get input from Deano and Nick. Not sure how to do that while this is in the Garage.

Dave

 

[lazersteve]

Great start...

Here are some of my posts on CN safety

CN Posts

I've been stripping scrap with CN on and off now for 6 years. Chris and Rick may have more to add.

Steve

 

[4metals]

Excellent links and a good start on explaining how to use the cyanide for different methods and applications.

The thing that most people do not realize is just how little cyanide can kill you. Unlike a drum of fuming smelly acid, cyanide solutions look rather tame. It feels a little slimy due to the alkalinity but they look pretty harmless. Remember different processes utilize different concentrations of cyanide. Electroplating baths run up as high as 8 to 10 grams of free cyanide per liter of solution, and bombing solutions run around 30 grams per liter. Leaching solutions run from parts per million all the way up to several grams per liter.

The most common way people are poisoned by cyanide is ingestion. And the most common reason it is ingested is because the container, beaker, bucket or tank was not labeled properly. Remember I said it looks pretty tame. A few milliliters of solution accidentally ingested can kill you. The measurement of toxicity of any poison is measured by a term called LD50. The meaning of LD50 is the quantity of toxic material, expressed in grams per kilogram of body weight that will kill 50% of those exposed in 3 days. So the Lethal dose to kill 50%.

Some exact numbers are as follows;

Potassium cyanide ingested at the rate of 0.3632 grams for a 160 pound person will kill 50% of those exposed in 3 days
if you up the dose to .55 grams the kill rate is 90%.

The 3 days is an overstatement when it comes to cyanide but cyanide does not have it's own rating system so they use the LD50 system
Specific rates are LD50 for KCN is 5 mg/kg and for NaCN it is 6.4 mg/kg. The time to kill someone is measured in minutes for a toxic dose. That's why spies on the old movies carried cyanide pills, it's quick.

These rates are determined by feeding the poisons to rats, so please notice no refiners were sacrificed to attain this data!

Translation to common English; It don't take a lot!!!!

So if you take anything from this it is plainly label your containers and don't ever eat anything in the Cyanide room.

The second most common method of exposure is being exposed to the toxic gas. Cyanide salts and acid makes Hydrocyanic acid. (Made famous in America from its use in the gas chamber)

This is why you have a room for cyanide work and a room for acid work, and never the 'twain shall meet. It takes more cyanide to gas someone because the gas is diluted in the air but that doesn't make it any less deadly.

Despite the hazards, it is an amazing and selective chemical for selective stripping of gold and silver allowing for complete recovery and a waste stream that can be effectively treated. So think of this post as an attempt to make you aware of the hazards so you can evaluate your own application to determine the benefits.

 

[goldsilverpro]

Here's a post I made.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=24567&p=259896&hilit=cyanide#p259896

The "cyanide itch" I mention is a very real thing. I seem to remember that about 1/3 of the population have a skin sensitivity to cyanide.

 

[g_axelsson]

Thanks Chris, that link was the same as the one I used as reference in the bottom of the post. :lol:

I added a section for Low level exposure in my post.

Göran