Sulfamic acid for denoxing solutions

[lazersteve]

Copper cementation requires the solution to become saturated to be sure you get all of the values out. This saturation makes the solution very thick and in turn the cemented values do not settle or filter well without diluting the solution. A fair amount of the values strongly adhere to the copper surface as well, which requires additional steps to remove and recover. It's also not practical for me (from a customer turn around time perspective) to wait for the cementation process to complete, especially for large batches (eg. 10 gallon of pregnant solution or more). I have no desire to play with any more chemicals than are required to complete the batch as quickly and completely as possible for my customer. I wish I could drop everything in one bucket and wake up the next morning to a pile of gold powder at the bottom of a barrel, but as we all know, it simply doesn't work like that. Time is money for me, so I do not do things just for the fun of it like I used to in the early days of my refining. I have several other hobbies away from refining where I do things for fun.

Evaporation is out of the question for any batch over a few liters in my opinion.

Using a gold button to kill off the excess acid is just another chemical means of killing the nitric that is no different than using sulfamic acid (in my opinion), it just costs more up front (Au verses sulfamic prices), takes longer, and requires better bookkeeping on each customers batch.

My waste removal is farmed out, so I don't worry about the waste stream except to make sure to keep ammonia out of the stream for the most part. My waste collector has never had any issues with what he gets, and I make a point to keep in touch with him after each batch is disposed of to fine tune what ultimately is going into the waste container. I pay for disposal by the gallon, so I try to keep the volume of my waste low by using as little water as required to complete any process. Using dry chemicals is a good way to reduce the final volume of your waste.

As a side note: Sulfamic acid works on not only dissolved gold solutions, but also on solutions containing PGMs.

Steve

 

[Lou]

It comes back to bite you during waste treatment as it is a chelator

.Sulfamic acid is used widely in descaling operations for rust removal and hard water scaling. I have used it in electroplating cleaning lines and never had any significant hold up of metals due to chelation when using classic destruct treatment systems. I always separate streamed EDTA rinses for that reason but never sulfamic rinses. Maybe the concentration or mixture was too dilute to effectively chelate the waste and it may be different with higher concentrations. (as in de-NOxing reverse AR solutions)

Can you be more specific Lou?

Seems to keep nickel in solution. Nothing a sulfide won't fix, but it's not desirable.

Unlike Steve, I don't use the powder.

 

[samuelbaldwin010]

I know this is kind of an old thread. I was reading through but, I didn't see anyone mentioning anything like alternatives for the powdered sulfamic if you were unable to find any, like me.
I have however, found out that lime away contains sulfamic (or at least one formulation of it does) and I was curious if anyone has had any experience with using it for denox? Or is it too diluted for use as denox agent?
Anyone with any insight they are willing to share would be appreciated!

 

[Darkthirty]

I know this is kind of an old thread. I was reading through but, I didn't see anyone mentioning anything like alternatives for the powdered sulfamic if you were unable to find any, like me.
I have however, found out that lime away contains sulfamic (or at least one formulation of it does) and I was curious if anyone has had any experience with using it for denox? Or is it too diluted for use as denox agent?
Anyone with any insight they are willing to share would be appreciated!

https://www.homedepot.com/s/sulfamic acid cleaner?NCNI-5South Beaverton Portland OR

 

[eaglekeeper]

I know this is kind of an old thread. I was reading through but, I didn't see anyone mentioning anything like alternatives for the powdered sulfamic if you were unable to find any, like me.
I have however, found out that lime away contains sulfamic (or at least one formulation of it does) and I was curious if anyone has had any experience with using it for denox? Or is it too diluted for use as denox agent?
Anyone with any insight they are willing to share would be appreciated!

There is several flooring supply stores in Portland and you should be able to purchase sulfamic acid there.




Or at Lowes.....