Leaching of wet zinc smelting roasting material (3)

A section of the hot acid leaching process is shown in the next two figures.

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    Both processes belong jarosite process iron sink method, a first neutral leach residue is a flowchart of a direct thermal acid leaching. The second flow chart is that Ma Rongjun et al. proposed to add a low acid leaching between the neutral leaching and the hot acid leaching, and the low acid leaching liquid directly sent the immersion iron. The main difference between the two processes is the low acid leaching and pre-neutralization processes. The common point of the two processes is to achieve efficient use of the acid in the hot acid leaching section and to reduce the acidity of the iron removal solution. The difference is that one neutralizes the hot acid leaching solution with neutral leaching slag. The other is neutralization with calcine. The advantage of the above figure 1 is that the pre-neutralization section has a relatively low solid-liquid ratio and is advantageous for liquid-solid separation. The advantage of Figure 2 above is that the hot acid leaching section has less processing capacity, which saves equipment and energy consumption.
The technical conditions for a period of hot acid leaching are as follows:
Start acid 100 ~ 200g /L
Final acid 30 ~ 60g /L
Temperature 85 ~ 95 °C
Time 3 ~ 4h
Liquid to solid ratio 6 to 10 ( leaching start)
The next two flow charts are examples of two stages of hot acid leaching and goethite iron removal process. The neutral leaching slag of the two processes is leached by a superheated acid after hot acid leaching, and the hot acid leaching liquid is directly sent to remove iron. The difference is that the heat and reductive acid leaching Wei Weiai combined in a process plant, the advantage by the addition of hot acid leaching of zinc sulfide concentrates having a reducing effect, and therefore promote the decomposition of Zn0 · Fe ₂ 0 _3, and Speed ​​up the leaching rate. The thermal acid leaching of the Barron plant is at a temperature of 85 ～ 90 ° C , the final acid 50 ~ 60g When the /L ratio is basically the same, the leaching and reduction times are 6h and 7h , respectively, for 13h . The combination of hot dip and reduction in the Vivel plant takes only 4 hours . The two factories have higher zinc leaching rates due to the increase in superheated acid leaching. The leaching rate of Zn0 is reported to be 99.9 %, the leaching rate of Zn0·Fe ₂ 0 ₃ is 98%, the leaching rate of ZnO is 90% , and the total leaching rate of zinc is 99.5% . Lead-zinc smelter in northwest China using multi-stage hot acid leaching process, to obtain good results. [next]

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