Hello everyone, yet another newbie here. First post.
I have been reading for some time now and I am currently doing first tests in test tubes and small beakers.
I have been able to dissolve material with AP and I have tried to observe the different states of AP but I have not yet figured out what's normal and desirable and what's not.
I have done tests with some connector pins with gold plating. My HCL is 33 % technical grade bought from a drug store and my H2O2 is 9 % also from a drug store. So they should be OK.
I first made very small tests in a test tube. 5-6 pins and a few ml of HCL plus a few drops of H2O2. Quite quickly the color turned nice green and then darker and darker. After it was completely "black" I added a drop or two of H2O2 and green color returned and the process seemed to accelerate. Soon it was black again. The fluid seemed to have some golden flakes in it. I managed to fush some of them with water and HCL and even I managed to dissolve them in HCL-CL. Never got anything precipitated (except some salt) nor I got any result with stannous but it could be the sample was just so small (appr. 0.3 grams of pins).
Another couple tests went the same way.
Next I made a little bigger test but still a small one. Like 5 grams of those same pins in an erlenmayer with 30 ml of HCL and 5 ml H2O2 (I assume the 6:1 ratio is correct as it's 9%). The reaction started nicely again and the color turning green and then darker and finally to black. Next morning the color was changed into much lighter, transparent smokey green. I added a couple ml of H2O2 and the reaction seemed to move on and soon it was black again. some time later the color again seemed to lighten and I added a little HCL and a little H2O2. Again, it got darker and some time later it's now again quite transparent. It's been now 48 hours and still there seems to be a lot of the base metal parts not dissolved and the soltuion is quite transparent.
In Steve's AP video the colour turns black and with adding H2O2 it turned light green as in my test tubes but this experiment it's so different. Now I have appr. 50 ml of solution and 5 grams of pins only partly dissolved and I don't want to believe that the amount of acid is not enough. So what's wrong here? What does the different colors of AP mean? When should I add what? And how much base metals could I expect to dissolve in HCL and with what amount of H2O2?
I am sure someone has already experienced the same so I hope I could get some advise. Search function and a lot of reading hasn't given an answer to these questions.
Best Regards,
Tero
I have been reading for some time now and I am currently doing first tests in test tubes and small beakers.
I have been able to dissolve material with AP and I have tried to observe the different states of AP but I have not yet figured out what's normal and desirable and what's not.
I have done tests with some connector pins with gold plating. My HCL is 33 % technical grade bought from a drug store and my H2O2 is 9 % also from a drug store. So they should be OK.
I first made very small tests in a test tube. 5-6 pins and a few ml of HCL plus a few drops of H2O2. Quite quickly the color turned nice green and then darker and darker. After it was completely "black" I added a drop or two of H2O2 and green color returned and the process seemed to accelerate. Soon it was black again. The fluid seemed to have some golden flakes in it. I managed to fush some of them with water and HCL and even I managed to dissolve them in HCL-CL. Never got anything precipitated (except some salt) nor I got any result with stannous but it could be the sample was just so small (appr. 0.3 grams of pins).
Another couple tests went the same way.
Next I made a little bigger test but still a small one. Like 5 grams of those same pins in an erlenmayer with 30 ml of HCL and 5 ml H2O2 (I assume the 6:1 ratio is correct as it's 9%). The reaction started nicely again and the color turning green and then darker and finally to black. Next morning the color was changed into much lighter, transparent smokey green. I added a couple ml of H2O2 and the reaction seemed to move on and soon it was black again. some time later the color again seemed to lighten and I added a little HCL and a little H2O2. Again, it got darker and some time later it's now again quite transparent. It's been now 48 hours and still there seems to be a lot of the base metal parts not dissolved and the soltuion is quite transparent.
In Steve's AP video the colour turns black and with adding H2O2 it turned light green as in my test tubes but this experiment it's so different. Now I have appr. 50 ml of solution and 5 grams of pins only partly dissolved and I don't want to believe that the amount of acid is not enough. So what's wrong here? What does the different colors of AP mean? When should I add what? And how much base metals could I expect to dissolve in HCL and with what amount of H2O2?
I am sure someone has already experienced the same so I hope I could get some advise. Search function and a lot of reading hasn't given an answer to these questions.
Best Regards,
Tero
