I have a similar problem and yes it's all my own fault but I never really thought I'd get back into recoveries and refining again in any serious way, how little I knew.
All my solutions that have had values in are put into a large holding tank and more precipitant is added, ferrous or ascorbic and allowed to settle over at first many weeks or months but later a lot less time. From there it's drained into a tank to cement the copper out with iron and also of course any values...no problem with small quantities but as I got busier the volumes increased and so did the need for more buckets to cement the copper, one has to say it all got a little out of hand
I was then faced with around 40 kilos of copper with mixed values included, gold, platinum, palladium, rhodium and iridium, I know this from samples I played with and xrf scans, and a swine of a job to separate.
My thoughts led me to try a way to remove the copper, not completely, and leave the values and to this end I decided to filter and wash the cemented copper and then dry and crush it. Now the washes were probably not totally efficient nor was the drying so the copper started to verdigris or to give it it's chemical name form copper carbonate...hmmm now that at first stumped me but with a little research I found that this copper carbonate will dissolve in weak sulphuric acid but so too could some palladium and rhodium so I left a decent amount of copper powder and metal in the solutions in the hope that this would cement any values dissolved by the sulphuric and so far this seems to be working. The first 20 kilos or so is now down to around 1 kilo and the second batch is now been treated and hopefully will reduce accordingly and when all the sulphuric treatment is finished I will have an assay done to make sure I'm not throwing values back into the mix.
The one point that has been of benefit from this mess is the need to read and learn and to put better systems in place to catch any values but not in such big volumes and to that end I'm going to dissolve some of the copper sulphate crystals and drop out the copper as powder with zinc dust and use this to add to the solutions from the tank before they go for the cementation of the copper.
I can't swear to the efficiency of what I'm doing but if time isn't too important, which with this it isn't for me, then perhaps this might give other members ideas they can utilise in their own processes.
As I pointed out this is one very big problem which I can blame nobody but me for but in my own defence I never thought I would be processing as much as I have or have such a mix of values that were not expected.
All my solutions that have had values in are put into a large holding tank and more precipitant is added, ferrous or ascorbic and allowed to settle over at first many weeks or months but later a lot less time. From there it's drained into a tank to cement the copper out with iron and also of course any values...no problem with small quantities but as I got busier the volumes increased and so did the need for more buckets to cement the copper, one has to say it all got a little out of hand
I was then faced with around 40 kilos of copper with mixed values included, gold, platinum, palladium, rhodium and iridium, I know this from samples I played with and xrf scans, and a swine of a job to separate.
My thoughts led me to try a way to remove the copper, not completely, and leave the values and to this end I decided to filter and wash the cemented copper and then dry and crush it. Now the washes were probably not totally efficient nor was the drying so the copper started to verdigris or to give it it's chemical name form copper carbonate...hmmm now that at first stumped me but with a little research I found that this copper carbonate will dissolve in weak sulphuric acid but so too could some palladium and rhodium so I left a decent amount of copper powder and metal in the solutions in the hope that this would cement any values dissolved by the sulphuric and so far this seems to be working. The first 20 kilos or so is now down to around 1 kilo and the second batch is now been treated and hopefully will reduce accordingly and when all the sulphuric treatment is finished I will have an assay done to make sure I'm not throwing values back into the mix.
The one point that has been of benefit from this mess is the need to read and learn and to put better systems in place to catch any values but not in such big volumes and to that end I'm going to dissolve some of the copper sulphate crystals and drop out the copper as powder with zinc dust and use this to add to the solutions from the tank before they go for the cementation of the copper.
I can't swear to the efficiency of what I'm doing but if time isn't too important, which with this it isn't for me, then perhaps this might give other members ideas they can utilise in their own processes.
As I pointed out this is one very big problem which I can blame nobody but me for but in my own defence I never thought I would be processing as much as I have or have such a mix of values that were not expected.
