china lithopone in china

...

Nano-sized TiO2 generally shows low or no acute toxicity in both invertebrates and vertebrates. However, exposure of Daphnia magna to 20 ppm TiO2 for 8 consecutive days was found to cause 40 % mortality. Zhu et al. showed minimal toxicity to D. magna after 48 h exposure, while upon chronic exposure for 21 days, D. magna suffered severe growth retardation and mortality. A significant amount of nano-sized TiO2 was found also accumulated in the body of the animals. Similar findings with coated nano-sized TiO2 (T-Lite™ SF, T-Lite™ SF-S and T-Lite™ MAX; BASF SE) were reported by Wiench et al. Biochemical measurements showed that exposure to TiO2 NPs induces significant concentration-dependent antioxidant enzyme activities in D. magna. Lee et al. showed that 7 and 20 nm-sized TiO2 induced no genotoxic effect in D. magna and in the larva of the aquatic midge Chironomus riparius.

...

 Fourth, since the sulfate required for the production of the present invention is provided by the acid leaching slag itself, the mass fraction of the SO/- contained in the acid leaching slag is 15% or more, and the nanometer is prepared by using the acid leaching residue as the zinc and sulfate raw material of the lithopone. Lide powder products not only realize the resource utilization of acid leaching slag, but also turn waste into treasure, and treat and improve the acidic soil of acid leaching residue to purify the environment. Low production costs and simple operation. The metathesis reaction is carried out in a low-density ammonia system (the metathesis reactant is dissolved in recovered ammonia water), and the crystal nucleus formed is smaller. It is non-toxic and safe. The ammonia solution after synthesis and separation is returned to the leaching. There is no waste water in the whole production process. The produced waste residue meets the national solid waste discharge standard for efflux, conforms to the national industrial policy, and is an environmentally friendly “green” type process.

...
...