Ceramics composites from iron ore tailings and blast furnace slag

The search for materials and methods capable of reducing human impacts on the environment is of utmost importance nowadays. This study's primary purpose was to analyze the technical feasibility of ceramic composites production utilizing Fundão Dam's Iron Ore Tailings (IOT), Blast Furnace Slag (BFS) from charcoal, and Foundry Sand (FS) as partial substitutes for the traditional raw materials – sand and clay – for application in building industry materials. The composites were molded in rectangular specimens and fired at temperatures of 900, 950, 1000, 1050, and 1200 °C. The developed materials were analyzed and characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), Thermogravimetry (TGA), and Differential Thermal Analysis (DTA). The obtained materials had flexural strength modulus of up to 12.19 MPa, water absorption ranging from 2 to 22%, linear shrinkage ranging from 0.02 to 6.50%, and apparent density ranging from 2.03 to 1.63 g/cm³. The study of the internal structure formation process revealed the formation of amorphous structures in the composites. The results demonstrated that these waste materials may be jointly used in construction materials, contributing to the reduction of natural resource extraction, besides enabling their correct disposal, minimizing environmental impacts, and improving the life quality of the surrounding communities.     

Preparation and pore-forming mechanism of MgO–Al2O3–CaO-based porous ceramics using phosphorus tailings

A simple strategy for preparing MgO–Al₂O₃–CaO-based porous ceramics (MACPC) with high strength and ultralow thermal conductivity has been proposed in this work based on the raw material of phosphorus tailings. The effects of phosphorus tailings content, carbon black addition and heat treatment temperature on the properties of MACPC were studied, and their pore-forming mechanism during sintering was revealed. The results showed that the main phase composition of MACPC was magnesia alumina spinel and calcium aluminate after sintering at 1225 °C. Furthermore, the MACPC exhibited excellent comprehensive properties when 60 wt% phosphorus tailings and 40 wt% alumina were added, whose apparent porosity was 62.8%, cold compressive strength was 14.8 MPa, and the thermal conductivity was 0.106 W/(m·K) at 800 °C. The synchronously enhanced strength and thermal insulation properties of MACPC were related to the formation of uniformly distributed micropores (<2 μm) and passages in the matrix, which originated from the decomposition of phosphorus tailings and the burnt out of carbon black during the sintering process. The preparation of MACPC with high temperature resistance and excellent mechanical and thermal insulation properties with the raw material of phosphorus tailings provided an effective method for the high-value utilization of phosphorus tailings.     

Microstructural,hydraulic conductivity and geochemical changes of drying mature fine oil sand tailings in column experiments

This study offers new insights into two-lift deposition of mature fine tailings under atmospheric drying. The interaction of newly added lift and former lift(s) was evaluated using column experiments in terms of volumetric water content, electrical conductivity (EC), hydraulic conductivity, geochemistry and microstructure. Water content and EC followed the same trend and decreasing of water content appears to be responsible for significant reduction in EC. Evaporation on top of the column reduced the water content to almost zero. The obtained results support the coupling between the hydraulic and chemical processes that should be considered by active operators.     

细粒尾矿综合利用技术研究

姑山矿业公司为提高细粒尾矿的综合利用率，研究分析了细粒尾矿的性质，系统研究了尾矿含量、煅烧工艺制度对不同成分体系尾矿陶粒堆积密度、表观密度、空隙率、吸水率、筒压强度及软化系数的影响。研究得出了全尾矿陶粒、细粒尾矿+污泥陶粒、细粒尾矿+污泥+粉煤灰陶粒3种成分体系的尾矿陶粒较优的尾矿含量及煅烧工艺制度，且3种尾矿陶粒均可代替石头用作粗集料。     

The isothermal reduction kinetics of chromium-bearing vanadium–titanium magnetite sinter

The reduction of chromium-bearing vanadium–titanium magnetite sinter (CVTMS) by CO was investigated at 1123–1223?K. The reduction degree increased with increasing temperature. The isothermal reduction kinetics of CVTMS was analysed, according to Sharp analysis and ln–ln analysis, the kinetic mechanism of reduction process for all samples in different basicity can be represented as f(α)?=?1.61(1?α)[?ln(1?α)]^1–1/1.61. The reaction activation energy of all samples (R?=?1.9, 2.1, 2.3, obtained according to the components of the materials burdening used in sintering process) at different reaction degrees were calculated by the model-free method. And the pre-exponential factors of reaction also were calculated by the mathematical method. The rate controlling step for the reduction process under the present reduction condition was chemical reaction.     

A High Capacity All Solid-State Li-Sulfur Battery Enabled by Conversion-Intercalation Hybrid Cathode Architecture

As demands for electrochemical energy storage continue to rise, alternative electrochemistries to conventional Li-ion batteries become more appealing. Here, an intercalation-conversion hybrid cathode that combines intercalation-type VS₂ with conversion-type sulfur chemistry to construct high performance solid-state lithium-sulfur batteries is reported. The layered VS₂ nanomaterial features Li-ion transport channels, metallic conductivity, and active capacity contribution, all of which provide an ideal platform for the solid state S/Li₂S redox couple to unlock its high gravimetric capacity. The S/VS₂/Li₃PS₄ hybrid cathode composite is prepared by a facile, low-cost, and low-energy mechanical blending process. The S/VS₂/Li₃PS₄|Li₃PS₄|Li/In (or Li) all-solid-state cell exhibits sulfur utilization of ≈85%, with a Coulombic efficiency of close to 100%. High areal capacity up to 7.8 mA h cm⁻² with an active material loading (S/VS₂) as high as 15.5 mg cm⁻² is achieved.     

电感耦合等离子体原子发射光谱法测定钒钛磁铁矿中锌

钒钛磁铁矿中含有一定量的锌,在高炉冶炼过程中,锌被还原成金属锌,而金属锌会侵蚀炉体的耐火材料,因此在钒钛磁铁矿冶炼中锌是一种有害元素,需要对进入炉体中锌的含量进行严格控制。试样采用盐酸-硝酸-氢氟酸-高氯酸体系溶解,选择Zn 206.200nm作为分析谱线,采用基体匹配法绘制校准曲线消除基体效应的影响,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定钒钛磁铁矿中锌。锌含量为0.01%~0.05%(质量分数)时与其发射强度呈线性,相关系数为0.9999;方法检出限为0.0030μg/mL。按照实验方法测定两个钒钛磁铁矿样品中锌,结果的相对标准偏差(RSD,n=10)小于1%;加标回收率为98%~102%。     

磁铁尾矿与石灰石双掺生产优质水泥

受环保压力影响，西乡公司生产水泥用河道淤沙供应紧张，难以满足生产需求且价格上涨幅度较大，严重影响到水泥生产及成本，我们开展了磁铁尾矿在水泥中的应用研究工作，通过连续几个月的生产实践，对物料配比优化，磨机技术改造，实现利用磁铁尾矿与石灰石双掺解决混合材紧缺问题，降低了水泥生产成本，水泥质量及性能稳定。     

电感耦合等离子体原子发射光谱法在钒钛磁铁矿中钒化学物相分析中的应用

钒钛磁铁矿中钒的化学物相分析一般测定硫化物中钒、钛磁铁矿中钒、硅酸盐中钒和钛铁矿中钒共4项。其中硫化物中钒利用强氧化剂分离,钛磁铁矿中钒利用其强磁性磁选分离,硅酸盐中钒利用氟化铵-硝酸分离,最后从残渣中得到钛铁矿中钒,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定钒。试验对钒钛磁铁矿中钒的相态划分进行了统一,对各相态浸取溶剂进行选择及优化,确定分析谱线并计算检出限。按照实验方法测定3个矿区钒钛磁铁矿中总量钒和各相态钒,总量钒和钛磁铁矿中钒的测定结果与分光光度法测定值相一致;各相态钒测定结果的相对标准偏差(RSD,n=12)大部分在5%以内。各相态钒加和与总量钒进行比较,相对偏差在5%以内,满足《地质矿产实验室测试质量管理规范》要求。     

南美白对虾进食前后发声信号特点分析

为了探索南美白对虾进食前后发声信号特点和规律,首先进行了养殖虾塘环境下的实验,利用水听器与采集器采集信号;然后利用Matlab软件对信号进行频谱分析和时频分析,得到南美白对虾的发声信号规律。实验证明,在淡水养殖环境下,南美白对虾产生的声信号具有一定的规律,一般情况单个脉冲信号时长为0.005 s,主峰频率在2～10 kHz之间,投饵后主峰频率有所扩大,约在5～15 kHz之间。投饵后南美白对虾随着咀嚼活动的展开产生的信号增多,并且时频域特征明显与投饵前不同。该实验结果为利用南美白对虾产生的信号来控制投饵机实现按需投饵提供了可能。