Strengthening Sulfidation Flotation of Hemimorphite via Pretreatment with Pb2+

The conventional sulfidation-xanthate flotation process that consists of sulfidization with sodium sulfide, activation by heavy-metal ions, and collection with xanthate is not sufficiently efficient for treating hemimorphite, and the dosages of the sulfurizing reagent and metal ions are large. In this study, the sulfidation flotation (Pb2+ + Na2S + Pb2+ + xanthate) of hemimorphite was strengthened by pretreating with Pb2+ before sulfidation. Microflotation test results indicated that the recovery of hemimorphite increased by 5–10% after pretreatment with Pb2+. The comprehensive results of adsorption experiments, scanning electron microscopy–energy-dispersive X-ray spectroscopy, atomic force microscopy, and X-ray photoelectron spectroscopy indicated that a large amount of Pb2+ was adsorbed on the hemimorphite surface and entered the lattice, forming Zn(4−x)PbxSi2O7(OH)2·H2O. The newly formed component had an increased amount of surface sulfidation active sites and had the effect of induced crystallization, making the surface more effective for sulfidation. After the Pb2+ was added to the pulp, a large number of uniform and dense PbS species were formed on the hemimorphite surface, increasing the number of adsorption sites for xanthate and reducing the competitive adsorption of residual S2− on the xanthate

Evaluation of Immunogenicity and Safety of Vero Cell-Derived Inactivated COVID-19 Vaccine in Older Patients with Hypertension and Diabetes Mellitus

Background: To evaluate the immunogenicity and safety of the COVID-19 vaccine (Vero cell), inactivated, in a population aged ≥60 years with hypertension or(/and) diabetes mellitus. Methods: A total of 1440 participants were enrolled and divided into four groups, 330 in the hypertension group, 330 in the diabetes group, 300 in the hypertensive combined with diabetes group (combined disease group), and 480 in the healthy population group. Two doses of the COVID-19 vaccine (Vero cell), inactivated, were administered at a 21-day interval and blood samples were collected before vaccination and 28 days after the second dose to evaluate the immunogenicity. The adverse events and changes in blood pressure and blood glucose levels after vaccination were recorded. Results: The seroconversion rate of the COVID-19 neutralizing antibodies was 100% for all participants. The post-inoculation geometric mean titer (GMT) in the four groups of the hypertension, diabetes, combined disease, and healthy populations were 73.41, 69.93, 73.84, and 74.86, respectively. The seroconversion rates and post-vaccination GMT in the hypertension, diabetes, and combined disease groups were non-inferior to the healthy population group. The rates of vaccine-related adverse reactions were 11.93%, 14.29%, 12.50%, and 9.38%, respectively. No serious adverse events were reported during the study. No apparent abnormal fluctuations in blood pressure and blood glucose values were observed after vaccination in participants with hypertension or(/and) diabetes. Conclusions: The COVID-19 vaccine (Vero cell), inactivated, showed good immunogenicity and safety in patients aged ≥60 years suffering from hypertension or(/and) diabetes mellitus