Dhasayvsk Posted Sunday at 05:58 PM Posted Sunday at 05:58 PM (edited) Hi guys! I was trying to follow the instructions @mx5kevin told to make PbO2 in this post: But something odd happened. The electrode forming was first covered by copper, than by a white color, and after that a shy gray, as you can see in the pictures: This happened in about 3 hours. The concentration of lead nitrate was 250g/liter, I was not using TritonX and the current was 0.7ma. Those were the differences. Do you guys have any idea what was going on? I'm thinking that the readish color is lead oxide, and not copper Edited Sunday at 06:04 PM by Dhasayvsk
mx5kevin Posted Sunday at 06:42 PM Posted Sunday at 06:42 PM (edited) 1 hour ago, Dhasayvsk said: Hi guys! I was trying to follow the instructions @mx5kevin told to make PbO2 in this post: But something odd happened. The electrode forming was first covered by copper, than by a white color, and after that a shy gray, as you can see in the pictures: This happened in about 3 hours. The concentration of lead nitrate was 250g/liter, I was not using TritonX and the current was 0.7ma. Those were the differences. Do you guys have any idea what was going on? I'm thinking that the readish color is lead oxide, and not copper The pH must keep under pH6 this is important, use small amount of HNO3. Keep it hot the solution. The coating should be dark gray. The rate of formation of the coating itself is encouraging. If the solution is not acidic enough, unwanted substances may precipitate. Or maybe you measured something wrong, maybe too much copper but it's also possible that the raw material is contaminated. Copper can also precipitate if the solution is not acidic enough add to it more nitric acid. If there is any material that doesn't belong there, it tends to precipitate out at the beginning. If you use a little more volts at the beginning you can create a very thin alpha coating on which the beta can then be coated. Edited Sunday at 07:23 PM by mx5kevin
Dhasayvsk Posted Sunday at 07:38 PM Author Posted Sunday at 07:38 PM I'm giving 2 volts, and the amperage is 0.7A. The pH is just a little above 1, something between 1.2 and 1.3. I checked it when I started, and when it was over. Both times the pH remained the same! I saw it two days ago (2 weeks after the electrodeposition) and the gray areas stayed the same, while the orange ones were oxidized. Do you think would be a good idea to let the electrodeposition happen for, like, 8 hours? Because one hour or another, the lead needs to start coating the electrode, right?
mx5kevin Posted Sunday at 08:24 PM Posted Sunday at 08:24 PM (edited) 1 hour ago, Dhasayvsk said: I'm giving 2 volts, and the amperage is 0.7A. The pH is just a little above 1, something between 1.2 and 1.3. I checked it when I started, and when it was over. Both times the pH remained the same! I saw it two days ago (2 weeks after the electrodeposition) and the gray areas stayed the same, while the orange ones were oxidized. Do you think would be a good idea to let the electrodeposition happen for, like, 8 hours? Because one hour or another, the lead needs to start coating the electrode, right? At the beginning, you can make a quick alpha coating, but very thinly. The beta coating should be applied as slowly as possible. There are the following problems: 1. the factory setup are using high density 1.6-1.75g/cm3, high purity graphite which is a light-graied, very hard material. Welding carbon rod are soft material compared to it. 2 problem Here wold be the first alpha coating will be the best Alkaline Lead Tartrate (Alpha Lead Dioxide bath) without pinhole problems. This gives a denser structural pre coating. 100g Potassium Sodium Tartrate, KNaC4H4 O6.4H2O 50g Sodium Hydroxide, NaOH 96g Lead Oxide, PbO Dissolve in the order listed in distilled water to make 2 liters of solution. Heat to 60C to complete solution of Lead Oxide. Cool and filter through sintered glass. Bath pH is about 13. For beta coating Lead Nitrate PbNO3 375g/l Copper Nitrate CuNO3 14g/l TritonX 100 0.5g/l Nitric acid 5g/l pH controlled with nitric acid: pH 1.5-6.0 Solution temperature 70-90°C Anode current density: 10 to 100 mA /cm2 1.46V is required for the formation of the dioxide layer Current maximum 2.2V 0.4A Download the Chlorates and Perchlorates archive from here the APC forum, it includes detailed studies on the homemade lead dioxide anode. The problem with homemade lead dioxide anodes is that the perchlorate solution seeps through the poles and quickly disintegrates attacking the graphite and the anode are demaged. This is where the problem will arise when making perchlorate. However, it works well in a pH controlled chlorate cell. But you must not use too many amperes in the chlorate, perchlorate because the electrode will fall apart. You have undertaken a very difficult task. Edited Sunday at 08:51 PM by mx5kevin
mx5kevin Posted Sunday at 08:45 PM Posted Sunday at 08:45 PM (edited) The PbO2 electrodeposition can happen really fast way. You can see deposits within an hour, but you have to be careful to make it happen as slowly as possible. https://www.bitchute.com/video/b7DoUveEIwDX In poor quality, such an electrode can be made very quickly, even within 1-2 hours, but they also fall apart quickly. Depending on the electrode, they usually allow up to 36 hours coating time required for these electrodes. The ones on YouTube that show anodes quickly made from welding electrodes have so far quickly disintegrated for everyone here in a chlorate or perchlorate cell. One problem is that the solution slowly seeps through the lead dioxide layer, and the graphite begins to wear away and eventually the anode are crashed. Or if the lead dioxide coating is of poor quality, it will wear off. Edited Sunday at 09:01 PM by mx5kevin
mx5kevin Posted Monday at 09:32 AM Posted Monday at 09:32 AM It is worth inserting a piece of copper instead of the electrode if any parameter has been changed. And observe in that test electrode what the coating is like. In a more acidic solution, smaller PbO2 crystals form. But you can also dissolve PbO2 with too much nitric acid. It's possible that the electrode is red because some lead dioxide is deposited, but the nitric acid dissolves it, leaving only a copper with small amount of mixed PbO2 coating. This is a typical process where detailed questions need to be worked out.
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