Cyanide/Cyanate leaching using Brackish Water?

[Punterr]

Dear Esteemed Members..

Would anyone happen to know if using brackish water or sea water as the water source would have a detrimental effect when using CN type lixivants? Would the salt destroy the CN complexes?

I am sure sea water would be ok for Hypo type leaching but I am not sure for CN.

Any ideas or info would be most welcome..

 

[Lino1406]

Dear Esteemed Members..

Would anyone happen to know if using brackish water or sea water as the water source would have a detrimental effect when using CN type lixivants? Would the salt destroy the CN complexes?

I am sure sea water would be ok for Hypo type leaching but I am not sure for CN.

Any ideas or info would be most welcome..

No problem with sea water, as air-oxygen is also soluble in it (needed for the operation)

 

[Punterr]

No problem with sea water, as air-oxygen is also soluble in them (needed for the operation)

Thanks Lino.. what about the chlorine/chloride would that be a problem for the CN?

 

[Lino1406]

Thanks Lino.. what about the chlorine/chloride would that be a problem for the CN?

Chlorine reacts with CN

 

[Punterr]

Chlorine reacts with CN

Yes, that is why I asked about the sea water with CN. I am not sure if the chloride/chlorine (NaCl) in the sea water is 'locked up' or free to react with and damage the CN.

 

[Lino1406]

Chloride does not react with CN

 

[Punterr]

Chloride does not react with CN

Ok, that is good to know, so I can use sea water to mix with the CN for leaching.. i will do some tests and report back later..

Many thanks

 

[Ultrax]

It depends on the MgCl2 concentration in the seawater.
MgCl2 will increase NaCN's consumption significantly, raise alkalinity, and

2NaCN + MgCl2 -> Mg(CN)2 + NaCl
2NaCN+ 2H2O -> 2NaOH + 2HCN
NaOH + MgCl2 -> Mg(OH)2 + 2NaCl
2NaCN + 2H2O + MgCl2 -> 2HCN + Mg(OH)2 + 2NaCl

Mg(CN)2 in solution rapidly hydrolyzes and forms insoluble Mg(OH)2.
The cyanide effect of MgCl2 (aq) in NaCN (aq) is to precipitate Mg (OH)2 and form free HCN in the solution. Be careful.

 

[Punterr]

It depends on the MgCl2 concentration in the seawater.
MgCl2 will increase NaCN's consumption significantly, raise alkalinity, and

2NaCN + MgCl2 -> Mg(CN)2 + NaCl
2NaCN+ 2H2O -> 2NaOH + 2HCN
NaOH + MgCl2 -> Mg(OH)2 + 2NaCl
2NaCN + 2H2O + MgCl2 -> 2HCN + Mg(OH)2 + 2NaCl

Mg(CN)2 in solution rapidly hydrolyzes and forms insoluble Mg(OH)2.
The cyanide effect of MgCl2 (aq) in NaCN (aq) is to precipitate Mg (OH)2 and form free HCN in the solution. Be careful.

Ok, noted, many thanks.
Is it a similar reaction set for Cyanate (OCN)?

 

[Ultrax]

Hydrolyzing way is different for NaOCN.
But if you have an iron oxides (rust) in your seawater you may receive HCN.
Сan't tell the quantitative conditions, I just don't remember exactly.

In any case, it is better to desalt the water. For insurance against surprises

 

[Lino1406]

Hydrolyzing way is different for NaOCN.
But if you have an iron oxides (rust) in your seawater you may receive HCN.
Сan't tell the quantitative conditions, I just don't remember exactly.

In any case, it is better to desalt the water. For insurance against surprises

As Mg+Ca concentration is roughly 0.1%, an experiment with seawater may be worthwhile assuming you have a good reason for it

 

[Ultrax]

Magnesium concentrations in natural seawater are between 1250 and 1350 mg/l, around 3.7% of the total seawater mineral content. Dead Sea minerals contain a significantly higher magnesium chloride ratio, 50.8%. Each liter of Dead Sea water contains about 170 grams of magnesium chloride.

Safety rules are written by blood. HCN doesn't forgive negligence.

 

[Punterr]

Hydrolyzing way is different for NaOCN.
But if you have an iron oxides (rust) in your seawater you may receive HCN.
Сan't tell the quantitative conditions, I just don't remember exactly.

In any case, it is better to desalt the water. For insurance against surprises

As far as i can tell there is hematite in the sea water as a solid and there is also magnetite.

When i pull the ore from the sea, there will be a quantity of salt remaining, it is possible to rinse but is an extra step in the process, full 'desalting' would not be possible.

 

[Punterr]

As Mg+Ca concentration is roughly 0.1%, an experiment with seawater may be worthwhile assuming you have a good reason for it

Yes, i have a good reason..

 

[Lino1406]

Do you plan heap leaching? Another system?

 

[Punterr]

Do you plan heap leaching? Another system?

The ore will be ground up to 100% passing #100 mesh and then dewatered a bit, but still dampish, then vat leached and then dumped into a pad for draining, the pregnant leach will be put through resin to collect the metals.

 

[Lino1406]

Looks as all unwanted precipitates, suspensions can be disposed off by the system itself or vacuum filtration (refering to magnesium hydroxide, rust etc)

 

[BlackLabel]

But Punterr, please keep your waste solutions off the sea.

 

[Punterr]

But Punterr, please keep your waste solutions off the sea.

Of course BlackLabel, any and all waste solutions will be kept away from the seas....Why would you even say this...???
This conversation/post is about chemestry NOT environmental protection..
Please treat me with a little more respect than this, you don't know me, you have never spoken to me before, please dont assume I am a moron and refrain from issuing these type of posts in the future.. Many thanks Brother...

 

[BlackLabel]

Hi Punterr,

You're right.

I'm sorry, I didn't mean to blame you.

In my fantasy, I saw a remote little bay with a little cabin. Fresh water is rare (maybe collected rain water) and the next sewerage is miles away.

In reality, mabe your shop is located in a harbor city with a harbor basin right in front of and you just want to safe fresh water.

Sorry, peace brother!
With best regards.