Potassium cyanide with hydrogen peroxide

[Ayham Hafez]

You need to read more than one article stating something, before making up your mind,
there are millions of articles out there and not all are applicable in all conditions.
Many of which might not be trustworthy or targeting your specific situation.

Nest, are you sure you understood the article and all its ramifications?
This is an absolutely must, with regards to Cyanides even more so.

Pleas do not venture into new processes until you run it by us to get some feed back on its safety and viability.

Yes you alright, I always try to test before get

I always added a small amount of lye to my solutions which helps to allow the cyanide to be more aggressive and work slightly longer I believe but making the solution more aggressive will dissolve base metals just the same.
Working with cyanide is almost an art you have to adjust the amount of reagents used to achieve the desired reaction , every new product you have to recover the values from needs trial and error tests and careful examination, even the last time I processed using cyanide I had to adjust to achieve the desired yield and within an acceptable time.
To make it very plain working with cyanide is or can be highly complex and even more so if you are running mixed product that includes mixed boards which will have different metals on them.
I ran several tons of similar plated product over a few years and if memory serves me correctly the best yield we could get was around 90% , the rest was inaccessible as it was either covered or within the product and without dissolving the whole product or shredding it which would require very heavy equipment was recovered by the base metal refinery later.
If 100% recovery is what you need do not use cyanide , if you can accept 90% then it may be the process for you.

90% recovery rate is more that I looking for, if I can process pcb with cyanide as a one step process that will save me a lot of time and effort.


How long time you wait till cyanide dissolve gold plated on pins? And what is the cyanide and NaOH ratio you use?

 

[Yggdrasil]

Yes you alright, I always try to test before get

90% recovery rate is more that I looking for, if I can process pcb with cyanide as a one step process that will save me a lot of time and effort.


How long time you wait till cyanide dissolve gold plated on pins? And what is the cyanide and NaOH ratio you use?

Did you read and understand what Nick said?

 

[nickvc]

Yes you alright, I always try to test before get

90% recovery rate is more that I looking for, if I can process pcb with cyanide as a one step process that will save me a lot of time and effort.


How long time you wait till cyanide dissolve gold plated on pins? And what is the cyanide and NaOH ratio you use?

If you are processing many different boards from different manufacturers and from different dates then you will struggle as some may strip quickly exposing base metals while others stay well coated and once the base metal is exposed then it really slows down or even stops the gold from dissolving.
You keep asking questions that only you can answer I can’t tell you as I don’t have the product or your process methods but in my opinion I’d strip the pins from the boards, or if labour is cheap pay someone to do it, and then sort by whether magnetic or not and then put them in a concrete mixer with a stainless barrel add the pins cover in your solution and switch it on, as to what ratio you will have to play around to see what works for you and your needs.
There is no way I can tell you how long it will take it will all depend on the plating thickness, the substrate material and the ratio of chemicals you eventually decide on, you are going to have to find this out by trial and error…