Cyanide treatment

[shift_540]

I am a marine science student doing a study on the treatment of cyanide in the marine environment. Would like to know what a good treatment for a major spill would be, how long the area would remain toxic and if possible the effects of the treatment on life (if any left in the area). The type of spill I am researching is cyanide from mining practices. Any help on these question or any information regarding cyanide would be greatly appreciated. I have refered to the internet and scientific journals with no real luck. Thanks for the time.

[John Cuthber]

Cyanide certainly hydrolyses in water so it will go away eventually, even without outside help. Also, while it is very toxic there are biological mechanisms for detoxification.

Hydrogen cyanide is volatile and will disperse into the atmosphere by evaporation; once in the air it will be destroyed by the same sort of mechanisms that degrade other organic matter in the air..

Not sure how much this helps but it might give you an idea where to look.

[Icemelt]

Shift_540 hopefully this may help.

The popular notion of the poison “cyanide” refers to potassium cyanide, although in reality poisoning by cyanide is very rare.

The chemical formula is KCN, which is usually dissociated into K+ and CN- ions when dissolved in water.

The CN- ion is called an anion and it is negatively charged, since it has pinched an electron from the potassium atom, which now becomes the positively charged cation K+.

The potassium ions are not dissimilar to the sodium ions Na+ found in salt water, so a spillage of a solution of potassium cyanide into sea water would I suspect regrettably mix very efficiently !

It is likely that a normal cleanup exercise would be almost impossible due to the rate of dispersal.

However it might be appropriate to hoover up all the dead animals and plants so that the remaining living organisms wouldn’t get secondary poisoning from feeding on them.

The CN- ion is the bit that is highly poisonous.

This cyanide CN grouping can also exist in gaseous form, when combined with a single hydrogen atom to form the gas hydrogen cyanide HCN, which is a very poisonous gas at temperatures >26°C.

The cyanide CN grouping can also combine with itself to form the molecule N≡C−C≡N or (CN)2 which is a colourless gas at NTP, behaving much like a halogen, and is also highly toxic.

Half lives of cyanide gases are between 1 and 3 years, and spillages in tropical warm water will have very different results to spillages in Arctic cold water, so this is something to take into account.

My suspicion is that it could be a KCN solution that is used in mining to extract precious metals by complexing them into a compound such as KAu(CN)2. I would imagine this would then be precipitated out of solution for subsequent efficient shipment as a solid, whilst the solvent would be enriched locally ready for re-use. In this scenario a gold atom combines with the cyanide group to form a complex anion Au(CN)2-. Another example of complex anions are the ferrocyanides. Whilst, when mixed with acid, potassium ferrocyanide K4[Fe(CN)6] could react to release the very toxic hydrogen cyanide, by itself the compound is almost non-toxic. It is therefore important to establish in which form the cyanide is being shipped, and also the surrounding temperatures, before you could accurately predict the effects of a spillage.

[shift_540]

Just a quick thankyou the information provided led me on the right path it was extremely helpful and really appreciated thanks again.