livinthedream said:
I guess it depends on how/whether I'll be able to find sources of material going into the future. For now, I just want to cash this in asap. A furnace would be a failry large investment for myself I suspect, but that would be really cool. No idea how much one would be. All I have now is torch that uses O2.
While the reduction can be done by torch, it's not the recommended practice. The flux required is rather aggressive, and the material should have a sufficient soak time for all of the metals to agglomerate.
The majority of us build our own furnaces. It' not a tough job, but one should have need before attempting the project. It does cost a little if you intend to build one that will endure. Commercial refractory, to me, is a must.
Given your circumstances, unless you intend to pursue further refining, it stands to reason that a furnace is not for you.
The Au Ihave is 4 9's. I guess I'll go t his route. I just wanted to make sure I'm not going to end up loosing any of that also because I have some strange chemistry in my sol'n. I'll weigh it first, and just put in excess.
There's a couple things that might be helpful here. The gold I added was always in a button form, so it could be recovered easily. If you use small bits, there's a small chance you won't recover all of them easily, especially if you have an abundance of nitric in solution. An ounce of nitric has the potential to dissolve a troy ounce of gold, so it should be clear that you may end up with a multitude of tiny bits, or you may even dissolve them totally and still need more.
It is relatively common for a beginner to use way too much acid. The ramifications of excess acid don't sink in until you are the one called upon to expel the excess, plus it's hard for one without experience to identify a solution that is free of nitric. As the level diminishes, reaction becomes quite slow. That would be particularly true if you didn't heat your solution.
Would overnight generally be sufficient time?
I am unable to answer that question unless you heat your solution. If you do, and you don't have too much water present, the solution will react relatively quickly with any added gold, assuming you have free nitric. The best way to address this issue is to insert the gold and continue to heat the solution, covered with a watch glass. If there is nitric present, assuming you have free HCl, you will see the familiar brown fumes forming in the beaker, and bubbles will emanate from the bits of added gold. Once the addition of HCl makes no difference to the performance, you can then remove the watch glass and allow the solution to evaporate. It changes color as it condenses, although with the garbage included with your lot, the color would be hard to predict. I would suggest it would be something like a dark green. It's much easier to work with relatively pure solutions, so you might keep that in mind for future operations. Rule of thumb is to always remove all base metals before dissolving the values. It's not always possible.
Remember, this go around, I'm not concerned in having pure precipitate. I just want to make sure all the Au is in it. The buyer will melt it all down, determine the % of Au while molten, and buy based on this. He'll finish refining or whatever he wants to do with it. I'll be happy to drop all the Al, and everything else out as long as all the Au comes with it. I won't have created some type of Au salt that won't drop out using SO2 having done this, correct?
Most likely, that's correct. The real problem is that when you combine various elements, some of them are very troublesome when in solution. Tin, for example, or aluminum, make filtration very difficult. There are some simple procedures you can follow to minimize, or even eliminate, the problems, however. The other problem is the credibility of the buyer. If you open the door to suggestion that your gold is not of high quality, you can safely assume that it will be far worse than it is. GSP has a favorite saying. The refiner is the last liar. My personal experiences with major refiners is that he is correct. They are, in general, notoriously dishonest in their dealings with low volume customers.
It is for good reason that you should study Hoke, and it is also for good reason that you should begin processing in small increments. The concept remains unchanged when you go to larger volumes, but the processing time is much shorter for small batches. That allows you to make the proper observations and to improve your procedures instead of finding yourself in a huge mess, with a lot of values tied up in something that may require cementation and a start from scratch. That, too, is part of your learning experience, but you are far better served to have such experiences in small dosages, so you don't get discouraged.
Refining is one of the simplest functions you can learn. It is not necessarily reliant on skill, but more so on following strict guidelines. If you pay attention to commonly accepted practice and don't get creative until you have a firm understanding of refining techniques, you should be able to turn out quality that rivals industry.
I understand your position with this lot of values, but for future application, shoot for higher quality. It's not only in your best interest, but you will build a far more respectable reputation with those that matter.
Harold
