某难选煤系硫铁矿工艺矿物学研究

某地区煤系地层中普遍产出硫铁矿,但非常难选。为此,以当地某矿山的硫铁矿样品为代表进行了工艺矿物学研究。研究结果表明,该类矿石难选的根本原因在于：黄铁矿嵌布粒度微细并且与脉石矿物的共生关系密切而复杂,欲使黄铁矿单体解离度达到80%以上,需将矿石磨至10 μm以下。     

Effects of refractory elements on the microstructure and creep behaviour of nickel-base cast superalloys strengthened with high volume fraction gamma-prime phase

Microstructural observations and creep measurements at elevated temperatures were carried out on nickel-base cast superalloys strengthened by 0.65 atomic fraction gamma-prime (y'J phase with varied concentrations of Ta, Wand Mo and with elements commonly used in practice. The variations in the amounts of the refractory elements considerably altered the morphologies and the quantities of carbides as well as γ and γ’ eutectics. The steady-state creep rate for these alloys was related to lattice mismatch between the γ and γ’ phases as well as to the aluminium concentration in the γ’ phase. The effect of the elements on creep rupture life was in the order W>Ta>Mo.     

Dissolution behaviour of MgO based refractories in CaO–Al2O3–SiO2 slag

Abstract

Magnesium oxide (MgO) based refractories are widely used in secondary refining processes, and their dissolution into refining slag is the primary cause of their shortened lifespan. The dissolution rate was investigated for sintered MgO and commercial MgO–C and MgO–Cr₂O₃ refractories in a synthesised 50CaO–45Al₂O₃–5SiO₂ liquid (mass-%) slag. The change in slag composition was measured after a refractory sample was placed into the molten slag that was stirred by flowing argon gas at 1773?K. The dissolution rate of the sintered MgO was above those of the MgO–C and MgO–Cr₂O₃ refractories under the same gas flowrate, although the dissolution rate of all samples increased as the gas flowrate was increased from 25 to 75?mL·min^??1. The slag containing 5?mass-% FeO considerably promoted the dissolution of the MgO–C refractory because of the oxidation of carbon by FeO. The dissolution of all the refractories was greatly affected by penetration of the liquid slag, with the mass transfer of MgO in the penetrating slag at lower gas flowrates likely being the rate controlling step. At high gas flowrates, Ar bubbles covered the surface and blocked the contact between the liquid slag and the solid phase, reducing the dissolution rate.     

Sintering of clay-chamotte ceramic composites for refractory bricks

Clay-chamotte composites were realized for manufacturing refractory bricks. We used two kaolinitic refractory clays mined in Cameroon and two calcined clays (chamottes) with a large grain size (0.1–4 mm). Clay-chamotte composites containing various quantities of chamotte (0–50 wt%) were shaped and sintered at 1200–1350 °C. The structural characteristics of composites indicated the presence of quartz from the initial clay, cristobalite and mullite. SEM observations revealed very heterogeneous microstructures where porosity is weakly distributed and large pores are entrapped at the vicinity of large chamotte and quartz grains. In general, the global porosity increases with the chamotte content. A specific interpretation of the matrix role on the global sintering behaviour reveals that only a part of the matrix acts effectively. Since the most part of the global porosity is within the matrix, it is distributed in matrix zones, which participate effectively to sintering and in inert matrix zones where larger pores occur. The global mechanical strength is controlled by the matrix behaviour, but the high porosity of this phase is unfavourable to high strength values. Besides, the occurrence of larges pores and local cracks at large grain interfaces from thermal stresses are critical flaws, which reduce the mechanical strength.     

Bauxite Based Refractory Bricks for Hot Blast Stove YB/T 5016-2000

1Scope This standard specifies the technical requirements, test method, inspection rules, packing, marking, transportation, storage and quality certificate of bauxite based refractory bricks for hot blast stove.     

异型耐火砖熔芯快速机械化成形技术研究

针对当前异型耐火砖形状复杂难以实现机制成形而导致生产率较低的问题,提出了采用熔芯机压成形的新原理,并在此基础上设计了此种成形系统模具结构实现快速成形。采用多体系统动力学软件ADAMS对成形模具结构进行仿真分析,结果显示此种结构能够快速实现异形耐火砖的压制成型。虚拟仿真和生产实践表明采用熔芯成形技术能更好的实现异型砖的机械化生产,提高生产效率。同时,快速成形新原理的提出为以后其它异型砖的成形制造奠定基础。     

锅炉碳化硅质卫燃带上灰渣扩散行为

采用扫描电镜、能谱分析仪、X射线衍射等方法对燃煤电站锅炉SiC质卫燃带上结渣渣样进行了测试,并就紧贴卫燃带渣样断面的物相转化及结渣方向的扩散特性进行分析研究。结果表明,灰渣结晶度变化主要取决于钙长石、铁尖晶石和SiO2的物相与晶相的转化,而且越靠近SiC质卫燃带表面,灰渣成分细化越显著。灰渣中的碱性离子成分在紧贴SiC质耐火板的渣样中扩散均匀,并沿结渣断面方向的扩散逐渐趋于热力学稳定状态,有效避免Si质量分数高的煤灰对SiC质卫燃带侵蚀结渣作用。     

硫氰酸盐体系从难处理硫化金精矿中氧压浸金研究

以难处理复杂硫化金精矿为原料,采用碱性—硫氰酸盐溶液加压氧化工艺浸出其中的金。采用L16(45)正交试验评估了碱用量、浸出剂浓度、反应温度、反应时间和氧压大小对金浸出率的影响。结果表明,反应温度是影响金浸出率的最显著因素。最佳条件是:反应温度180℃、硫氰酸钠浓度2.0 mol/L、碱用量为理论量的0.8倍、反应时间8 h,氧压1.2 MPa和木质磺酸钙为矿的1%,此时金平均浸出率可高达95.29%。     

我国高铝矾土均化料的技术进步

介绍了我国高铝矾土加工特点,提出了我国高铝矾土的发展方向应该是均化与提纯,重点介绍了矾土基均化料的工艺路线和技术发展,并对进一步产业化提出建议。     

化工自热式转化炉的设计与制造

介绍了自热式转化炉的设计与制造的关键和难点,有针对性地提出了解决难点的特殊设计及工艺方案,对类似设备的设计与制造奠定了基础。