china arti titanium dioxide

At present, the domestic wet zinc smelting mainly adopts the roasting-leaching-electrowinning production process, and the zinc content in the acid leaching residue is generally 8-15%, some up to 20%, and the sulfur mass fraction is 6-12%, of which sulfuric acid The root mass fraction is 15-30%, mainly in the form of 0^0 4 (in this ammoniatic environment, the leaching rate of sulfate leaching in multiple stages can reach 70%). The zinc in the acid leaching residue is mainly in the form of ZnFe 2 0 4 . In order to recover these zinc, the treatment methods are currently available in the fire method and the wet method. The fire method is the rotary kiln evaporation method (Wilz method) and the fumigating furnace evaporation method. . The wet method has hot acid leaching or high temperature pressure leaching. The fire treatment process is long, the equipment maintenance is large, the investment is high, the working environment is poor, and a large amount of coal or metallurgical coking coal is consumed, which has low efficiency and large environmental pollution. Therefore, it is usually leached by hot acid or high-pressure leaching. These methods still have the disadvantages of: 1 consumption of a large amount of acid, low leaching rate, due to the large amount of calcium sulfate, calcium sulphate and other ultrafine particles to isolate the zinc oxide particles, resulting in Electrolytic zinc enterprises are difficult to leach in acid environment, and the second weak acid leaching is not meaningful because the recovery rate is too low. 2 If leached with strong acid, although ZnFe 2 0 4 is destroyed, the leaching rate is improved, but the iron leaching rate is also high (up to 60%). The pressure of iron removal is large, and more reagents are consumed. 3 High temperature and high pressure equipment is corroded. Serious, complicated equipment investment; 4 high operating costs, poor economic returns. 5 The last slag discharged is acid leaching residue, which brings new pollution to the environment. It has to be cured and landfilled, which not only pollutes the environment, but also wastes resources.

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Infrared analysis showed that the characteristics bands for the bare nanoparticles are still exhibited in the vitamins@P25TiO2NPs spectra, such as a wide peak in 450–1028 cm−1 related to the stretching vibration of Ti-O-Ti and other peaks in 1630 cm−1 and 3400 cm−1, which represent the surface OH groups stretching. The IR spectrum of vitaminB2@P25TiO2NPs showed signs of binding between compounds. The OH bending peak (1634 cm−1) corresponding to bare nanoparticles disappeared, and the NH2 bending band characteristic of vitamin B2 appeared (1650 cm−1). The IR spectrum of vitaminC@P25TiO2NPs also showed signs of successful functionalization. Bands at 1075 cm−1; 1120 cm−1; 1141 cm−1 were observed, which are originated by CsingleO-C vibrations present in the vitamin C. The intense band at 1672 cm−1 is attributed to the C = O stretching in the lactone ring while the peak at 1026 cm−1 is ascribed to the stretching vibration Ti-O-C. Wide bands at 3880–3600 cm−1 are related to stretching vibration OH groups, but those disappear in the modified nanoparticles spectrum. These observations confirm the interactions between the P25TiO2NPs and the vitamins [35].

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