A week later and many hours of reading, I have here a simple version of my proposed process. I have been obsessing over this plan for a month or so, and it feels good to have it thought out and on 'paper.' However I am no fool and I haven't built all this yet, so as I said I want you pros to give me all the pointers before I spend any money. I want to do this a long time and I want to be able to do it safely so I stay alive long enough to see some results. So this is basically a normal process, but I want to make sure I have everything well thought out.
My specific goals here are (1) using smelting and electrorefining to minimize exposure risks when done safely, and (2) be very strict with environmental impact, even if it makes the process less efficient. (3) I want to always keep this small and one man-able, with a monthly schedule so I can work it as a part time job and let the cells run. I am not trying to make money nor have the cleanest gold around. I can't really avoid acids all together but I surely (4) don't want to waste them either.
The TL
R is a standard copper cell, slimes are collected with silver metal, run through a silver cell and those slimes are processed. So for the curious, here we go.
Let us assume proper PPE is used at all times and anywhere chemical reactions are mentioned, they would be performed in a fume hood. For material, I plan to collect and manually brake down e waste, and collect or snipe plated jewelry.
For chemicals, I will would build a fume hood of course, and invest in lab grade glass ware. As required I would produce home made nitric acid, which I've actually done before. Potassium nitrate is reacted with sulfuric acid and then distilled to azeotropic nitric acid. Sulfuric acid is available as drain opener. potassium nitrate is available as a stump remover.
I plan to try to recycle my electrolyte. It seems like copper sulfate will crystalize if dried, and the crystals can be quick rinsed through a colander with cold distilled water, dried and stored to be reused. the base metal salts and the insoluble colloids could build up in a bucket until I need to dispose of them in a sealed container or do something else. For the nitrate solution, I can displace the silver with copper, and then basify the copper nitrate solution with sodium hydroxide under the fume hood and recover some copper metal, evaporate sodium nitrate and then react it with sulfuric acid again to make more nitric acid.
Next is reacting azeotropic nitric acid with .999 silver to form silver nitrate, or reacting sulphuric acid with copper to produce copper sulphate. My plan was to build a solar evaporation shed, basically a greenhouse with a vent fan, and evaporate solutions to dryness, and measure and weigh the crystals and store them so I can constitute electrolyte as needed. Then using a gravitometer, make jugs of electrolyte solution, clearly labeled and normalized to even density.
For e waste, I would build or buy an electric oven, and a propane or electric forge with precise temperature control. I can use the pyrolizer design on the forum there with some modifications to build an afterburner unit for e waste. I have seen people using a large graphite crucible to white ash cpus, so some standard combination of that depending on the type of waste I would come by, with the standard process. Ashed chips and etc are added to an improv ball mill, the old cement mixer with steel balls added, and ran overnight.
I would use the low tech standard gravity seperation with a 5 gallon bucket on the the powder and sediments in the ball mill using dish soap or jet dry as a surface tension breaker. Waste water and ash is poured into a kid pool under greenhouse plastic to evaporate water and collect ash for disposal.
After obtaining the metallic fraction, I would melt and pour shot as standard. I figure this would be a good point to also make shot from plated jewelry and treat them the same since it would be mostly copper and probably less than 1% PMs.
Here's where I want to get weird. rather than cast anodes, I wanted to make a copper sulfate cell and run it with the shot like Kadriver's silver cell that is now world famous.
My copper cell would be filled with copper nitrate solution and the anode basket would be a 4x6 or so rubbermaid container with holes in it and I wanted to use old polyester shirts from goodwill as an anode filter bag unless there's a good reason not to.
I understand the importance of anode and cathode efficiency, so I would try to match the surface area facing the cathode to the cathode area itself.
After so many runs, the electrolyte is siphoned off through a shop towel in a colander over a bucket to filter it, and the solution PH is checked and ammended as neccessary, the slime filter material is put into a casserole dish and ashed and roasted in an electric oven at say, 600c to ash the filter material and then convert sulfides to oxides. the dry ashed material is allowed to cool, then put into another bucket. The cats are collected in a bucket and eventually melted and poured as shot for making clean copper sulfate later, and excess is cast into clean bars and stacked as a low budget savings.
Here's another place I think I would want to deviate from the standard. So after my roasted stored copper anode slimes hit a critical mass, I would stir the dry mixture to homogenity, then take a weighed sample, use a measured amount of lead as a collector metal and cupel it in a cupel cup from Legend in the forge at a controlled temp with air exposure or the electric oven with the door open and determine PM concentration of the whole batch. Then, I would use sterling scrap, and mix the slimes with flux at a weight targeting some percentage of PMs, some of which is silver, to the weight of actual silver in the sterling and use that as a collector metal for whatever gold may be present.
Then, I would smelt and pour the silver into shot and run the impregnated silver through a silver nitrate cell, again copying the Kadriver design because it is brilliant. The silver cell slimes would then be as clean as I would think they could get, since some metals in e waste are soluble in sulfuric and some soluble in nitric. Apparently the silver cell slimes will contain predominantly silver, so my idea is that these slimes could go directly to aqua regia, the silver would convert to silver chloride and then get trapped in the filter. The pregnant AR solution would be precipitated, probably with SMB because I can buy it. At this stage, I would take the silver chloride laden filter and dry it and save them up and then smelt a lot of them with a reducing flux such as flour or other electron doners to recover silver metal.
I think I would save what will probably be a small amount of gold powder for several cycles until I had enough to work with, and do a second refining before melting a bead. What do yall think? What am I missing? What do I not clearly understand? What is going to kill me here?
I still have to determine the right fluxes, and I have an idea of how I could exploit anode inefficency in a two chambered cell with a salt bridge to make more copper sulfate or try to clean dirty electrolyte by using a variable power supply to target certain impurities and have them plate out. That is an open question and I will continue to read the forum like I'm cramming for an exam.
as an aside, electrowizardry is really the obsession, so I would want to, for fun, make many electrolysis cells, to make hydrochloric acid and sodium hydroxide from salt, or make a birkeland eid reactor for nitric acid from the air. Thank you to anyone with feedback or just for reading this far!
