How to reduce the antimony content in the supernatant in the standard wet zinc smelting process
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The company uses the standard wet zinc smelting process; the supernatant obtained from the neutral leaching of the roasted ore contains high levels of antimony, with Sb levels exceeding 4 mg/L. This severely affects the normal operation of the purification process. There is an urgent need for methods and techniques to reduce the antimony content in this supernatant (Note: The smelting method used at Zhuzhou Smelting Plant is the same as that of our company, and the composition of the roasted ore is essentially identical; the antimony content in the supernatant can be kept below 1 mg/L, usually around 0.6 mg/L.) I would appreciate it if experts could provide some guidance. Thank you! ljp312@163.com
Send over the leaching endpoint, the acidity and iron content in the oxidation tank, as well as the amount of ore added; also provide the iron content in the roasted ore
Composition of the roasted ore (%): Zn: 52.34, available Zn: 46.23, Fe: 12.7, Cu: 1.32, Cd: 0.17, total S: 1.56, available S: 0.84, unavailable S: 0.72, Pb: 1.29, SiO2: 1.9, Sb: 0.044, Co: 0.0019, Ge: 0.0021； Oxidizing solution: Iron: 0.8---1.5g/L, acidity: 70--80g/L ； Final pH: 5.2–5.4 (at cold temperature). Daily processing capacity for the roasted ore: around 500 tons ；
It’s mainly because the antimony content in the ore is relatively high. It is recommended to improve the ore blending; meanwhile, if it is only one batch of material, enhance the control over the leaching process – primarily by increasing the iron content in the oxidizing solution and setting a later leaching endpoint – and also use a three-stage purification process.
The Sb content in the ore is not high; it’s relatively low. The Zn grade of the concentrate you use is a bit low, with high levels of Cu, S, and Fe. There are two aspects to consider: first, once the oxidation tanks are properly set up, it’s necessary to control the pH value at the outlet of each tank, as well as the temperature； Second, check whether there are factors in the mixture that result in high Sb levels.
Actually, this situation is easy to handle using the modified iron alum method: the supernatant is first oxidized with hydrogen peroxide, and then neutralized with roasted ore, with the acidity controlled at a pH of 5.2. In this way, the Sb content in the supernatant can be kept around 1 mg/l, thereby reducing the pressure on the purification process.
This post was last edited by The distance to happiness on 2009-5-18 08:13. It only shows that your roasted ore is of poor quality! The iron content is too high; strictly, Fe should not exceed 8% ； The Sb content is not high; the inability to remove Sb is mainly due to problems with the boiling roasting process. When roasting is carried out at high temperatures with an excess of air, and in the presence of iron oxide, antimonates that are difficult to volatilize are formed and end up in the roasted ore, making it difficult to remove them during leaching. It is recommended to adjust the ore blending or change the operating parameters of the fluidized bed furnace.
Thank you to the brothers upstairs; your suggestions have been extremely helpful to me!
Only increasing the iron content in the medium soak bottom water and slightly raising the final pH value!
The main thing is to properly control the iron content; a slight increase in iron levels can help reduce the amounts of AS and Sb.
Everyone has finished speaking; I’m speechless!