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The recovery of gold from copper anode slime has been paid increasing attention by researchers at home and abroad. To realize the higher reduction rate of gold and purity of gold powder, a novel technology is proposed for reducing gold chloride solution by controlling potential in this work. First, the effects of excess coefficient of Na2SO3, reaction temperature, reaction time and initial H+ concentration on the reduction rate of gold were investigated. The optimized conditions were determined as 30°C for the reaction temperature with an excess coefficient of Na2SO3 of 1.43 and an initial H+ concentration of 1.0 mol/L for a reaction time of 15 min. Under the optimal conditions, the purity of gold powder can reach 99.9%. Then, the relationship among solution potential, concentration of gold ion and reduction rate of gold were explored, indicating that the concentration of gold ion can be reduced to 99.7% when the solution potential is

The thermodynamic analysis on the reduction smelting of stainless steel pickling sludge was reported in this paper. The predominance area diagram of Fe–Ni–Cr–C–O system, and phase diagrams of CaF2–SiO2–CaO–Al2O3–MgO system were first thermodynamically constructed. The effects of temperature, CaF2 content, and SiO2 addition on the melting temperature and viscosity of slag were calculated. Then the reduction smelting experiments were carried out under various SiO2 addition at 1400 °C. The thermodynamical results show that the reduction reaction can occur in the Ni + Fe + Cr2O3 phase stable region by controlling the relevant thermodynamic conditions during reduction, which can realize the Fe–Ni phase enriched in the alloy. The experiments results indicate that the variation of SiO2 addition can affect the distribution of Fe, Cr, and Ni elements in the alloy and slag. When the SiO2 addition is 50%, the contents of Fe and Cr in the alloy can reach 72.39% and 20.98%, respectively. The mineralogy of the reduction products demonstrated that the distinguishable crystal phase in the alloy mainly contained FeNi intermetallic compounds, and the slag was mainly composed of fluorite and calcium silicate.

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.

A fundamental theory on pyrometallurgic direct smelting of waste printed circuit boards was investigated in this work. First, the effects of the Fe/SiO2 (mass ratio) and CaO/SiO2 (mass ratio) on the liquidus temperature and viscosity of slag were systematically analyzed at a PO2 value of 10–12 atm. Then, a verification experiment was carried out. Thermodynamic calculation results showed that the liquidus temperature of slag first decreased then increased as Fe/SiO2 and CaO/SiO2 were increased. At 1250°C, the viscosity of slag is lower than 0.5 Pa s in the Fe/SiO2 range of (0.8–1.2):1 and CaO/SiO2 range of (0.25–0.85):1. The verification experiment indicated that an alloy with high content copper can be obtained. Microanalysis of the alloy and slag demonstrated that the distinguishable crystal phase in the alloy mainly contained metallic copper, metallic iron, and a small amount of intermetallic compounds such as (Fe, Ni) and Ni3Sn2. The slag was mainly composed of fayalite (Fe2SiO4), calcium silicate (Ca2SiO4, CaSiO3), and gehlenite (Ca2Al2SiO7).

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.

Zinc leaching residue is an important secondary sources of zinc. To realize recycling utilization of this zinc secondary resource, a novel technology is proposed for the recovery of zinc from the z...

The oxidization of As(III) to As(V) is necessary for both the detoxification of arsenic and the removal of arsenic by solidification. In order to achieve high efficiency and low cost As(III) oxidation, a novel process of catalytic aerial oxidation of As(III) is proposed, using air as oxidant and Mn-loaded diatomite as a catalyst. Through systematic characterization of the reaction products, the catalytic oxidation reaction law of Mn-loaded diatomite for As(III) was found out, and its reaction mechanism was revealed. Results show that Mn-loaded diatomite achieved a good catalytic effect for aerial oxidation of As(III) and maintained high performance over multiple cycles of reuse, which was directly related to the structure of diatomite and the behavior of manganese. Under the conditions of a catalyst concentration of 20 g/L, an air flow rate of 0.3 m

Graphene as a new type of carbon material has drawn much attention recently. The remarkable properties such as low density, large specific surface area and unique electrochemical properties have attracted extensive research interests for their application in the energy storage area including metal ion batteries, metal-sulfur cells, metal-air cells, etc. For the applications in these areas, two-dimensional (2D) graphene sheets need to be assembled into three-dimensional (3D) graphene structures to control the electrochemical, mechanical and optical properties. In this feature article, the research status, application areas and drawbacks are reviewed. Fabricating graphene by the template, self-assembly and other newly developed methods, e.g., 3D printing, is discussed. The related research on 3D graphene-based materials in the energy storage area is also included. Finally, problems existing in the current fabricating method and future development directions are discussed.

With the development of open source projects, a large number of open source codes will be reused in binary software, and bugs in source codes will also be introduced into binary codes. In order to detect the reused open source codes in binary codes, it is sometimes necessary to compare and analyze the similarity between source codes and binary codes. One of the main challenge is that the compilation process can generate different binary code representations for the same source code, such as different compiler versions, compilation optimization options and target architectures, which greatly increases the difficulty of semantic similarity detection between source code and binary code. In order to solve the influence of the compilation process on the comparison of semantic similarity of codes, this paper transforms the source code and binary code into LLVM intermediate representation (LLVM IR), which is a universal intermediate representation independent of source code and binary code. We carry out semantic feature extraction and embedding training on LLVM IR based on natural language processing model. Experimental results show that LLVM IR eliminates the influence of compilation on the syntax differences between source code and binary code, and the semantic features of code are well represented and preserved.

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.

A simple and sensitive method based on high-performance liquid chromatography (HPLC) coupled with chemiluminescence detection was developed for the quantitation of kaempferol (KA) in rat plasma. Isorhamnetin (IS) was used as an internal standard. Plasma samples were prepared only by acidification with 20% phosphoric acid and protein precipitation using methanol. Good separations of kaempferol and internal standard were achieved with an isocratic elution using a mobile phase consisting of methanol and aqueous 0.4% phosphoric acid (47:53, v/v) within 25 min. The detection limit for kaempferol was 1.0x10(-9) g/ml. The mean accuracy was within 80.0-100.2%, and the intra- and inter-day precision had RSD (%)5.0. The sample preparation method was able to produce high recovery (or = 80.0%). The proposed method with wide linear range has been successfully applied to a pharmacokinetic study in SD rats after oral administration at a dose of 2500 or 1250 mg/kg bodyweight (BW) kaempferol. Kaempferol concentration was detectable in plasma up to 24 h post-dosing, and the pharmacokinetic parameters of T(max), C(max), AUC(0-infinity), MRT(0-infinity), and T(1/2) of kaempferol were reported.