I am processing silver from scrap rods, etc using nitric to dissolve, then hydrochloric to drop out of solution. I then use a vacuum filter to clean it until water coming from it is clear. From there I add water then Sodium Hydroxide and finally dextrose. Then I again filter till it is clear.
My first question is from what I am seeing on this forum that many people melt after originally dropping it out using copper, am I taking more steps than I need, with the cost of copper the hydrochloric is cheaper to use for me, also could I melt it after just dropping it out with the hydrochloric or would the purity be substantially less than the additional steps I am taking?
My second question is that I am just destroying crucibles. I use a fire clay crucible that I have been getting at legend and I get about one melt per crucible. The crucibles will have several colors from blue, green, and black sludge/slag. It is just eating them away. Most of my pours are around 10 pounds so the crucible is in the furnace for a while and I pour off quite a bit of liquid slag during the melt that is grey in color when it hardens. Because I am adding material as it melts down I have not been using much flux as I would just be pouring it off with the rest of the liquid slag during the melt. Not sure what I am doing incorrectly here. After my final step with washing it out, the liquid is basically clear so I just don't know if there is still contaminates in the silver. Am I not adding enough of the sodium hydroxide or dextrose to fully convert the material?
I have been doing this for about 10 months so am still very much a newbie at it. Any input would be greatly appreciated.
My first question is from what I am seeing on this forum that many people melt after originally dropping it out using copper, am I taking more steps than I need, with the cost of copper the hydrochloric is cheaper to use for me, also could I melt it after just dropping it out with the hydrochloric or would the purity be substantially less than the additional steps I am taking?
My second question is that I am just destroying crucibles. I use a fire clay crucible that I have been getting at legend and I get about one melt per crucible. The crucibles will have several colors from blue, green, and black sludge/slag. It is just eating them away. Most of my pours are around 10 pounds so the crucible is in the furnace for a while and I pour off quite a bit of liquid slag during the melt that is grey in color when it hardens. Because I am adding material as it melts down I have not been using much flux as I would just be pouring it off with the rest of the liquid slag during the melt. Not sure what I am doing incorrectly here. After my final step with washing it out, the liquid is basically clear so I just don't know if there is still contaminates in the silver. Am I not adding enough of the sodium hydroxide or dextrose to fully convert the material?
I have been doing this for about 10 months so am still very much a newbie at it. Any input would be greatly appreciated.