I have some questions regarding the wet-method recovery of molybdenum slag
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This post was last edited by zhaowendao on 2011-3-26 at 17:16. It’s a project I encountered; processes similar to it cannot be found in books on molybdenum metallurgy or tungsten-molybdenum metallurgy. The raw material is the waste residue resulting from the purification and impurity removal of APT, known as wet molybdenum slag (containing molybdenum, NH4+, WO3, Cu, etc.). After pulping, copper hydroxide, molybdenum sulfide, and calcium tungstate are produced via \"alkaline dissolution for copper precipitation + sulfidation for molybdenum precipitation + oxidation for tungsten precipitation\". There are also several stages of pressure filtration, washing, etc. in between; the details of these processes will not be discussed here. Caustic soda is added during copper plating. For the molybdenum sulfidation process, the information provided by the owner states that sodium sulfide is added. What is the valence of molybdenum? Can you write the main chemical reaction equations for this process? Oxidative tungsten precipitation involves adding nitrate for oxidation, followed by the addition of calcium chloride to obtain calcium tungstate. The main chemical reactions for copper deposition are shown below (written by me): NH4++OH—=NH3↑+H2O; WO3+2OH—= WO42-+H2O; Cu2++2OH—= Cu(OH)2↓. I’m unable to write the chemical equation for the molybdenum deposition process via sulfidation. It is said that hydrogen sulfide is produced. What is the purpose of nitrate oxidation? Could you provide the reaction equation? The chemical equation for tungsten precipitation is as follows: Na2WO4 + CaCl2 = 2NaCl + CaWO4. There are also requirements regarding intermediate process control, such as pH and the time required for dissolution and precipitation. There are quite a few questions, so it might be difficult to answer them; it would also be helpful if you could provide some reference books and materials. If you need more basic information, please leave a comment to let me know; I will do my best to provide it or consult with the owner. Thank you very much.
Take a look at the book titled “Molybdenum Metallurgy”
Molybdenum is generally required to be in the +6 valence state; lower-valence molybdenum and tungsten tend to polymerize. There is plenty of information available on the precipitation of molybdenum through sulfidation, and this method is one of the more common approaches for its separation from tungsten. For the precipitation of tungsten, calcium salts are used, and the pH level is usually alkaline; specific values can be found in books on tungsten-molybdenum metallurgy or in the book on tungsten metallurgy recently published by Wan Linseng
There are books on tungsten-molybdenum metallurgy, molybdenum metallurgy, tungsten metallurgy and tungsten materials and their processing, as well as molybdenum materials and their processing. Molybdenum sulfide precipitation is generally achieved by adding ammonia sulfide in an appropriate excess amount to the purification tank, depending on its concentration in the solution; this causes molybdenum to form complex precipitates ； Tungsten is primarily developed based on the technological principles of synthetic scheelite. In fact, the basic principle is similar; however, the specific manufacturing process is determined by the current price of metals. Multiple repeated processing steps can yield products with a higher purity, but this is often not cost-effective. Appropriate extractants and resins can also be used, referring to extraction or ion exchange methods.
OP. What organization do you work for? I have worked on similar projects. The reaction principles you listed are completely incorrect. . I don’t know what’s going on; I should be able to take on this project, as I do have the basic knowledge required..
-- If there’s an error in the principle of reaction, please give an example. --