Abstracts Selected from Naihuo Cailiao （Refractories）——A Chinese Language Bimonthly

Development and prospect of China＇ s refrac- tory industry equipment/Liu Junguang, WeiTong//Naihuo Cailiao. - 2013,47 （5） ：321 Alasttact： China＇ s refractory equipment including me- chanical equipment and kilns developed rapidly in the past two decades by technological innovation, advanced products introduction and independent research and de- velopment based on the former Soviet Union＇ s aid. In recent years, some high efficient equipment was devel- oped covering fields of fine grinding, burdening, mix- ing,shaping and firing,etc. In the new developing peri- od of refractory industry from big to strong, the ad- vanced refractory equipment shall be well researched and developed ,and be well spread taking the opportu- nity of raw materials homogenization and purification, capacity large scale, quality and pollutants reduction. improvement, energy saving     

Effect of Zircon Addition on Properties of Low Carbon Al2O3-C Refractories

Using tabular alumina as aggregate,tabular alumina fines, reactive alumina ultra-fines, aluminum powders,silicon powders,carbon black,flake graphite,B4C and zircon fines as matrix,low carbon Al2O3- C refractories were prepared. Influences of zircon powders additions( 0,3%,5% and 7%,in mass,the same hereinafter) on properties,phase composition and microstructure were investigated. The results show that the ZrO2- nitride can be in-situ formed through carbothermal reduction and nitridation in Al2O3- C refractories.With the increase of zircon powder,the oxidation resistance of the Al2O3- C refractories improves obviously,the oxidized layer thickness decreases from 7. 94 mm without zircon to 2. 71 mm with 5% zircon. HMOR at 1 400 ℃of the Al2O3- C refractories reaches the maximum 14. 9MPa when zircon addition is 5%. With the increase of zircon powder,the apparent porosity and bulk density change a little,CMOR and CCS increase.     

Study ＆ application of the desliming pond for flotation feed

Aiming at the special feature of Panyi Coal Preparation Plant, i. e. its coal slime being high-ash and highly degraded,a process of deslime-ilotation proposed;owing to the inferior performance of a small diameter classifying cyclone, a new desliming pond for flotation feed designed;introduced are its structure, working principle and special feature;based on ex periment results a regressive equation with 9 relevances derived in which the average velocity of upward current taken as the in dependent variable.     

Influences of Polyvinyl Alcohol on Synthesis of A95 Polycrystalline Alumina Fibers

In order to improve the spinnabilities of A95 alumi- na silica sols, the influences of addition and polymeriza- tion degree of polyvinyl alcohol on spinnabilities of alu- mina silica sols were researched. The viscosity and rheo- logical properties of the sols, mierostructure, infrared spectra, average diameter and diameter distribution oJ the gel fibers, BET specific surface area and distribution of pore diameters were measured. The results show that iJ there is no spinning agent, the A95 sols have no spinna- bility ; when PVA 2099 addition is in the range of l. 0% -2.0% （in mass, the same hereinafter） , the prepared sols have good spinnability, the gel fibers produced are thin and uniform, and the shot content is low ; BET spe- cific surface area and gas absorption amount of A95 polycrystalline alumina fibers are the largest when PVA 2099 addition is 2. 0% ; the gel fibers are thick and non-uniform, and the shot content is high when PVA 2099 addition is 4. 0% ; with polymerization degree oJ PVA increasing, the average diameter and diameter dis- tribution range of the gel fibers increase gradually; when using PVA 1799 and PVA 1899, respectively, the spun gel fibers are thin and uniform.     

Environmental-friendly Ramming Materials for Mud Package and Taphole of Large-scaled Blast Furnaces

The compositions, structures and properties of envi- ronmental-friendly ramming materials for mud package and taphole of large-scaled blast furnaces were studied. The results show that the formation of silica fibers makes structure of ramming materials dense. During the process of extruding mud and ramming materials, SiC is partly oxidized ; CaO , F% 03 and carbon penetrate towards the outer wall. The improvement of ramming materials can inhibit the penetration of molten slag, iron and carbon. The bulk density of environmental-friendly ramming ma- terials dried at 200 ℃ is 2.90 g · cm-3, the cold com- pressive strength of this kind of ramming materials dried at 200 ℃ is about 17. 0 MPa and fired at I 450 ℃ is about 39. 2 MPa.     

腐植酸对发展绿色低碳经济意义重大

<正>两百多年来,人类被"高碳"长烤。今天你"低碳"了吗?已成为人类共同的问候。哥本哈根世界气候大会刚结束,我们就迎来了以"腐植酸绿色产业与低碳经济发展"为主题的"第八     

Effect of Synthesized Forsterite Addition on Properties of MgO Based Castables

High purity forsterite with a mass ratio 60：40 of MgO over SiO2 was synthesized using magnesite, caustic magnesia and natural silica as starting materials. The synthesized forsterite aggregates were added in magnesia based custable with MgO -SiO2 -H2 0 binding system to replace dead burned magnesia up to 60 mass% at an in- terval of 15 mass%. Effect of the forsterite addition on properties ~f MgO based castables was investigated. Micro- structure analysis of related specimens was carried out by means of SEM. Special grade bauxite powders were also in- corporated to form spinel by reaction with magnesia, ac- companying volumetric expansion to compensate high tem- perature shrinkage. Bulk density of the castable decreases with increased forsterite addition. Properties in terms of cold crushing strength and cold modulus of rupture, hot modulus of rupture at 1 400 ℃ and thermal shock resist- ance can be improved by adding an appropriate amount of the forsterite aggregate, preferably around 30 mass%.     

Effect of ZnO on Oxidation Resistance of Low Carbon MgO-C Refractories

Al-containing low carbon MgO- C refractories were prepared using 70%( in mass,the same hereinafter)fused magnesia( ≤3 mm),24% fused magnesia powder( 0. 074 mm),3% flake graphite,3% Al powder and 4% phenolic resin( extra-added) as the basic formulation. Influence of ZnO addition on oxidation resistance of the materials was investigated by adding 1%ZnO to substitute fused magnesia powder. The relationship between in-situ formed spinel and ZnO in the matrix was discussed by comparing apparent porosity, cold crushing strength,and phase evolution of the materials matrix. The oxidation resistances of the two materials were compared by observing the formed dense MgO layer between the decarburized layer and the original layer.The result shows that adding ZnO in MgO- C refractories accelerates the in-situ formation of ZnAl2O4spinel and the formation of dense MgO layer,thus improves the oxidation resistance of the low carbon MgO- C refractories.     

Preparation of Single Phase Na-X Zeolite from Oil Shale Ash by Melting Hydrothermal Method

A single phase Na- X zeolite was synthesized from pretreated oil shale ash by alkaline fusion and hydrothermal treatment. Effects of the NaOH concentration,crystallization time and temperature on the formation of Na- X zeolite were studied in detail. The single phase Na- X zeolite powders can be prepared by alkaline fusion of pretreated oil shale ash at 600 ℃ for 1 h,and crystallization at 80- 100 ℃ for 8- 10 h with NaOH concentration of 3- 3. 5 mol · L- 1. Na- A zeolite appears when decreasing NaOH concentration, crystallization time or temperature,and an unnamed zeolite emerges when prolonging crystallization time or raising crystallization temperature. SEM micrographs suggest that the aggregates of Na- X zeolite particles have perfect dispersity and uniform granular with about 1. 5 μm in size,and most of the Na- X zeolite crystals display a regular octahedral structure with the size of about 500 nm. The specific surface area of the powders with single Na- X zeolite phase reaches the maximum value of 488. 163 2m2·g- 1,larger than that of multiple zeolite powders.     

Effect of Nano-ZnO or Nano-Y2O3 on Sintering Property of Fused Quartz Ceramics

Fused quartz ceramic was prepared using high purity fused quartz powder as starting material,separately introducing 1%,2% and 3%( in mass,the same hereinafter) nano-ZnO or nano-Y2O3as additive,molding at 50 MPa, firing in reduction atmosphere at1 300,1 350 and 1 400 ℃ for 1 h,respectively. Apparent porosity and cold modulus of rupture were tested and fracture morphology was analyzed by SEM. The results show that adding nano-ZnO or nano-Y2O3obviously improves sintering of fused quartz; adding nano-ZnO enhances modulus of rupture and decreases apparent porosity; the optimum addition of nano-Y2O3as sintering aid of fused quartz is 2%.     

Determination Method of Thermal Expansion Coefficient of Cordierite

Cordierite ceramics were prepared by using talc, bauxite and kaolin clay as starting materials. According to the detected resuh of XRD step-scanning from 25° to 35° by a high temperature X-ray diffractometer, 20 and d values of five peaks of cordierite crystal were ascer- rained. Then the least squares technique was used to cal- culate the crystal parameters ： at 25 ℃ , a = b = O. 981 8 nm, c =0. 927 4 nm, V=O. 774 3 nm3 ; at 600 ℃ , a =b =O. 982 0 nm, c=0.9252 nm, V=O. 773 5 nm3. The crystal volumetric coefficient of thermal expansion （CTE） and linear CTE along a and c axes were calcu- lated, αv = 2. 33 × 10-6℃-1, αa = αb, = 3. 27 × 10-6℃ -1 , αc = -4.19 ×10-6℃ -1. The average CTE of cordierite crystal is as low as O. 78 × 10-6℃ -1     

Properties and Microstructure Evolution of Al203-Si Material Fired in Different Atmospheres

A1203-Si composite specimens were prepared using fused corundum, ultra-fine α-A1203 and Si powder as starting materials and resin as binder. Effects of sintering atmospheres on properties, phase composition and microstructure of specimens after firing at 1 500 ℃ were investigated. The results show that： （ 1 ） after .firing in oxidizing or weak oxidizing atmosphere, there is some Si in the specimens and some glass phases containing mullite form on specimen surface, the density and strength at room temperature are relatively high, but hot modulus of rupture and thermal shock resistance are relatively poor; （2） after firing in, weak reducing or reducing atmosphere, Si reacts completely with CO or N2forming whisk-phere, Si reacts completely with CO or N2forming whisk-er-like SiC, granular Si2N20 or 0＇-SiAION, and the er-like SiC, granular Si2N20 or O＇-SiMON, and the thermo-mechanical properties of specimens are enhanced;（3） after firing in nitrogen atmosphere, Si reacts completely with N2, CO or G forming wbisker-like SiC and columnar β-SiA10N crystals, the hot modulus of rupture and thermal shock resistance of specimens are enhanced noticeably.     

Effect of Bauxite Aggregate on Properties of AI203-SiC-C lron Trough Castables

A1203-SiC-C iron trough castables were prepared using high alumina bauxite clinker GL-90 （ 〉 1 mm ） or homogenized bauxite GL-88 to replace the traditional brown corundum aggregates （ 〉 1 mm ） to reduce the cost of iron trough castables. Effects of the two bauxite aggregates on properties of iron trough eastables were investigated. The results show that the two kinds of bauxite affect flowability, bulk density, strength and slag corrosion resistance of trough castables differently. Compared with homogenized bauxite, high alumina bauxite clinker is more suitable to substitute brown corundum. The castables prepared from the bauxite clinker have similar performances with those prepared from brown corundum, especially used in medium or small blast furnaces with weak thermal impact and lower temperature hot metal. However, in large blast furnaces with severe thermal impact and high temperature hot metal, the performances of the two castables are significantly different. So it is suggested to use the brown corundum based castables in the front gyral zone of the slag skimmer.     

Development of Magnesium Aluminate Spinel Castable for Roof of EAF with High Molten Iron Charging Ratio

Specimens of magnesium aluminate spinel castable and calcium aluminate cement bonded bauxite based castable were prepared using special bauxite( particle size≤8 mm) and sintered magnesia as aggregates,SiO2micropowder,α-alumina micropowder and calcium aluminate cement as binders,drying,firing at 1 350 ℃and 1 500 ℃ for 3 h,respectively. The bulk density,cold modulus of rupture,cold crushing strength,permanent change in dimensions on heating,thermal shock resistance and slag resistance were determined. The results show that compared with calcium aluminate cement bonded bauxite based castable,the magnesium aluminate spinel castable has higher cold crushing strength after drying,better slag resistance but worse thermal shock resistance. Magnesium aluminate spinel based roof of EAF with high molten iron charging ratio has a longer service life.     

腐植酸对Pb~(2+)、Ni~(2+)、Cr~(6+)吸附性能的研究

研究了不溶性腐植酸对废水中重金属离子Pb2+、Ni2+、Cr6+的吸附性能及其影响因素,通过对反应接触时间、pH、初始浓度等影响因子的实验比较,确定了最佳反应条件,并分别以Frendlich方程和Langmuir方程拟合了不溶性腐植酸对以上3种离子的吸附等温线。结果显示,腐植酸对Pb2+、Ni2+的吸附等温线符合Frendlich方程,属于Frendlich吸附,而对Cr6+的吸附等温线符合Langmuir方程,属于Langmuir吸附。此外,通过实验证明重金属在不溶性腐植酸上的吸附主要以物理吸附为主。不溶性腐植酸对重金属离子具有强烈的吸附作用且吸附率稳定,可广泛用于去除污水中的重金属离子。     

Relationship Between Electric Properties and Temperature of ZrB,-SiC Composite Ceramic Heating Element

ZrB2 -SiC composite ceramic has been successfully introduced as heating element in super high temperature .field. This paper further investigated the microstructure of ZrB2 - SiC composite ceramic heating element and the relationship between electric properties and temperature. SEM photos show that the heating element consists of SiC grains and ZrBz grains smaller than 10 μm. The voltage and current gradually increase and the furnace tempera- ture rises lineally with heating time prolonging. The electric resistance increases linearly with the temperature rising. The service temperatltre of the heating element can reach 1 800 ℃ and 2 150 ℃ in air and argon at- mosphere, respectively.     

X-射线荧光光谱法测定土壤样品中卤族元素溴

探讨了用x-射线荧光光谱法测定土壤样品中微量溴的可行性。选择国家一级标准物质绘制校准曲线,用散射背景内标法和经验系数法配合校正基本效应,用Re作为内标绘制校准曲线,所得到的平均误差和相关系数都要优于Rhe作内标,粉末样品直接压片制样,方法检出限可以达到0.54X10,准确度、精密度均u丁满足国家规范要求。     

腐植酸产业低碳化技术解决途径探讨

<正>随着全球人口和经济规模不断增长,环境污染问题越发严重。近百年来,大气中二氧化碳(CO2)浓度的不断升高,导致全球正在经历一场以地球变暖为特征的显著气候变化。以低消     

Low Temperature Preparation of Carbide Coated Carbon for Refractory Castable Applications

Titanium carbide （ TiC ） coated graphite flakes （GF） and carbon black （CB） powders were prepared at relatively low temperatures （ 750 - 950 ℃ ） using a no- vel molten salt synthesis technique. The in-situ formed TiC coatings were homogeneous and crack-free and their thicknesses could be readily controlled/tailored by simply adjusting the Ti/C ratio. Compared to their uncoated counterparts, as prepared TiC coated GF and CB showed much improved water-wettability/dispersivity and rheological properties, and thus could be potentially used to prepare carbon-containing refractory castables.     

合成氨工艺操作仿真培训系统的开发应用

介绍了合成氨工艺操作员仿真培训系统的架构,合成氨OTS系统的前期准备、功能设计、模型开发、系统集成、测试验收等开发过程,实现的功能和应用情况。