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This study reports the fabrication of micro-sized spherical Mn3O4 particles using a precipitation conversion-roasting method. Morphological evolution of the product and mechanism of formation have been investigated. The results showed that the amount of alkali used in the precipitation conversion step had a significant effect on the morphology and particle size of the product. When mole ratio of the alkali to manganese increased from 1.6 to 4.0, morphology of the Mn3O4 precursor gradually evolved from an irregular cubic shape to a regular spherical shape, and finally, a regular cubic shape with uniform particle size. According to transmission electron microscopy (TEM) and selected area electron diffraction (SAED), morphological evolution of the Mn3O4 precursor was caused by the preferred orientation of crystal planes and supersaturation of the reaction system. Scanning electron microscopy (SEM) images of samples before and after calcination showed that morphology of precursor was inherited by the product obtained after calcination. Thus, spherical Mn3O4 particles, with uniform size and no agglomeration, could be prepared by precipitation conversion-roasting method.

The phase transformation behavior of lead and zinc in the high-lead slag reduction process was reported in this article. First, the occurrence state of lead and zinc in the slag and the phase transformation behavior of lead and zinc during reduction were investigated. Following, the thermodynamic modeling calculation for the reduction process was constructed and discussed. The results indicated that the zinc in the high-lead slag mainly existed in the form of zinc ferrite and silicate while the lead mainly existed in a silicate form. The XRD patterns of the reduced slag at different coal ratios demonstrated that the lead existing in the high-lead slag in a silicate form could be reduced into the metal phase while the zinc existing in the high-lead slag in the form of zinc ferrite (ZnFe2O4) could be converted into zinc silicate (Zn2SiO4), as the coal ratio increased. The thermodynamic modeling calculation results showed an agreement with the experiment analysis.

The thermodynamic analysis of bottom-blown direct reduction of lead sulfate with carbon was studied in this investigation, and the industrial verification test was carried out. The thermodynamic analysis results indicated that lead sulfate was easily decomposed into lead sulfide at $$P_{{{\text{SO}}_{2} }}$$ values above 10−3 atm and $$P_{{{\text{O}}_{2} }}$$ values below 10−12 atm. The lead sulfide could be converted into lead oxide or metallic lead in the decomposition of lead sulfate by the addition of Fe, FeS and CaO. The phase diagrams for the C–CaO–PbSO4 and C–Fe–PbSO4 systems were constructed at 1273–1573 K, indicating that the addition of coal, limestone and scrap iron during reduction could cause the slag chemical composition variation, which consequently changed the Pb-liq + CaS and Pb-liq + FeS zones area. The industrial verification test demonstrated that the average addition of limestone, scrap iron and coal in the direct reduction of lead paste was approximately 2.8%, 5.4% and 11.5%, respectively. The direct recovery rate of lead bullion was about 61%, and the total recovery rate of lead could reach 99%. The average content of lead, zinc and sulfur in the reduced slag was 2.42%, 1.55% and 0.51%, respectively.

An efficient synthesis of ODM-201's diastereomers has been developed from (R)-methyl 3-hydroxybutanoate or (S)-methyl 3-hydroxybutanoate, respectively, with high overall yield and excellent diastereomeric purity. The key step in this synthesis is the preparation of the key intermediate (R)-5-(1-((tert-butyldimethylsilyl)oxy)ethyl)-1H-pyrazole-3-carboxylic acid or (S)-5-(1-((tert-butyldimethylsilyl)oxy)ethyl)-1H-pyrazole-3-carboxylic acid through intramolecular 1,3-dipolar cycloaddition of the vinyl diazo carbonyl compounds.