Testing carbon blocks in the iron runner channel of a blast furnace

Conclusions The physical properties of worked carbon blocks correspond to the technical conditions for carbon blocks before their operation.Tests and investigations made show the advantages of widely using carbon-block linings in blast-furnace runners.It is necessary to develop a special design for runners with block linings which will ensure reliable fitting of the blocks, since the existing design of runners does not do away with the danger of floating.Iron runners should be lined with large blocks and the joints filled with carbon paste.After each iron tapping it is necessary to apply a protective coating of grog-clay or clay paste to the block lining by mechanical means with the aim of reducing the oxidation of the blocks when they react with atmospheric oxygen.Restorative repairs of the lining of the runners should be done by applying grog-carbon or purely carbon bodies to the repaired place.Production of carbon blocks for lining blast-furnace runners should be organized in plant conditions.     

Materials based on highly concentrated ceramic binding suspensions (HCBS). Comparative evaluation of the properties and in-service durability of pocket blocks of intermediate ladles

The Pervouralsk Dinas Plant has developed a technology for and started industrial production of pocket blocks based on bauxite ceramoconcrete for intermediate ladles. The structure and service properties of the blocks are compared with corresponding imported parts. The structure of the imported blocks is characterized by the presence of large (process) pores and the material is impregnated in service, whereas the developed blocks possess a homogeneous fine-capillary structure and are not impregnated in service.     

Production of high-alumina blocks for blast-furnace bottoms

Conclusions A hydraulic 1500-ton press is now used to produce high-alumina blocks 400×200×120 mm in size and 550×200× ×150 mm, in accordance with the specification for high-alumina bricks for large-size blast furnace bottoms. A technological system has been devised for manufacturing the blocks.The compressive strength of blocks 550×200×150 mm in size is about 100 kg/cm² lower than in the 400×200×100 mm blocks.Further improvement of the standard of high-alumina blast furnace blocks can be achieved by modernizing the 1500-ton press and adapting it for fine-grain mixtures, with a view to increasing the fraction finer than 0.088 mm in the mixture to 50–55%.     

新型高密度低气孔率电炉炭砖的开发与应用

分析了炉衬破损的原因，开发一种生产高密度低气孔率电炉炭砖的新工艺。结果表明，所得炭砖比普通炭砖有更高的体积密度、抗压强度，更低的气孔率，有利于提高炉衬的寿命。     

Magnesia blocks formed on a 3000-ton hydraulic press

Conclusions A production line containing a 3000-ton hydraulic press is used for manufacturing unfired chrome magnesite and forsterite concrete blocks for repairing the lining of heat-consuming plant by mechanical means.An analysis was carried out of the variation of the properties and chemical composition through the block and with the heat treatment temperature, and of the deformation and thermophysical properties and slag resistance of the blocks. The blocks can be recommended as lining material for the walls of the slag pockets and vertical channels of open-hearth furnaces of varied capacity, and for the floor and lower part of the walls of soaking pits.With these blocks the process of lining metallurgical equipment can be mechanized, labor productivity is higher, and the useful life of the individual lining elements longer. The savings achieved from using the blocks as lining material amount to 13–15 rubles/ton blocks.Translated from Ogneupory, No. 6, pp. 4–9, June, 1976.     

同向双螺杆捏合盘厚度对MAH接枝LDPE反应挤出过程的影响

研究了同向双螺杆挤出机中,捏合盘元件的不同厚度对低密度聚乙烯(LDPE)接枝马来酸酐(MAH)反应挤出过程的影响,并将其与常规螺纹元件进行对比。对挤出沿程中的3个位置和挤出机出口处进行取样,用滴定法测定这些样品的接枝率。结果表明,捏合盘元件所对应的样品接枝率高于常规螺纹元件,并且随着捏合盘厚度的增加,其所对应的样品接枝率下降。此外对于接枝反应而言,捏合盘元件的分布混合能力所起到的作用要高于其分散混合能力。     

Effect of the structure and properties of hearth carbon blocks on premature shutdown of electrolytic baths

Premature shutdown of electrolytic baths after a short service life leads to an increase in the cost of aluminum and serious economic losses. The most important element governing the service life of an electrolytic bath is the hearth that is lined with refractory hearth blocks. Presence of one concealed crack, that is exposed in the start-up period, may lead to failure of the whole electrolyzer in the first year of service. There are many producers and users of hearth blocks, and there are many specifications for cathode hearth blocks, although the requirements for them are selected in a very empirical way without considering actual service conditions. Scientifically based requirements for the material of hearth blocks is still in the formation stage. In 2004 in four aluminum enterprises under major repair hearth blocks were used from nine different producers that made it possible during evaluation of the statistics for shutting down young baths to determine the effect of the structure and properties of hearth blocks on the service life of electrolyzers and to formulate requirements for hearth block material. The contribution of permeable porous cathode carbon blocks on premature shutdown of electrolyzers by a mechanism of hearth uplift due to formation of a lens of electrolyte and refractory reaction products is demonstrated. Critical gas permeability and the maximum size of permeable pores in refractory hearth units are determined. Applicability of the first and second Hasselman criteria for the heat resistance of hearth block materials is demonstrated for predicting shutdown of young baths by a crack development mechanism in blocks due to thermomechanical stresses. __________ Translated from Novye Ogneupory, No. 4, pp. 3–12, April 2008.     

高炉炭砖性能与原料的选择

对不同煅烧温度下不同原料配比的实验结果进行了分析，得出：山西阳泉四矿无烟煤、云南昭通小发路煤矿无烟煤不宜作炭砖原料；太西洗煤厂精洗煤是高炉炭砖的优质原料；贵州织金煤矿无烟煤如果煅烧条件适宜，也可作高炉炭砖的优质原料；提高骨料的石墨化度或提高原煤的煅烧温度，是提高高炉炭砖导热系数的有效途径。     

Preparation and water sorption properties of cellulose-polypropylene glycol block copolymers

A series of cellulose-polypropylene glycol block copolymers have been prepared by techniques described previously. The chain extension reactions used for their preparation were confirmed by i.r. and intrinsic viscosity data. The water sorption of films of the blocks was determined and the results, calculated on the cellulose content, compared with various forms of pure cellulose. It was found that lower crystallinity of the blocks was indicated by the higher water sorption values. As the size of the cellulose blocks was decreased the water sorption also decreased but the smallest block sample gave a higher value. It is believed that the polypropylene glycol blocks exert a restraining influence on the water sorption which is eventually overcome by the decrease in the crystallinity of the cellulose blocks as their size decreases.     

多块修正技术——块修正技术的一般化推广

块修正技术可以大大加速数值法求解传热传质与流动问题时的收敛速度,双块修正技术使许多问题的收敛速度进一步提高.本文将块修正技术作了一般化推广,推导了多块(任意块数)修正技术的计算公式,研究了修正块数对不同问题收敛速度的影响,并找得了最佳修正块数与所研究问题的性质及网格结点数之间的一般关系.文中还研究了块修正与行TDMA迭代扫描次数之间的相互配合关系,并确定了每次块修正技术之后最佳的行(或列)TDMA迭代扫描次数.     

Cationic fluorene-thiophene diblock copolymers: Aggregation behaviour in methanol/water and its relation to thin film structures

Optical spectroscopy and photophysical measurements on cationic fluorene-thiophene diblock copolymers in solution show distinct properties for the two blocks, with clear indications of singlet exciton migration from the polyfluorene to polythiophene blocks. Electrical conductivity measurements and small angle X-ray scattering studies show that different aggregates are formed in water and methanol. This may be associated both with different solubilities of the two blocks and with the effect of solvent on the degree of dissociation of the ionic part. Atomic force microscopy (AFM) shows that different nanostructures are deposited from the two solvents, with large, vesicular structures deposited on mica from methanolic solution. Aggregation behavior is also found to be modulated, and to lead to more rigid thiophene blocks, by addition of the oppositely charged surfactant sodium dodecylsulfate.     

PE-HD/炭黑在捏合块元件内分散混合的数值模拟研究

使用Polyflow软件,计算了3种捏合块元件内高密度聚乙烯（PE-HD）熔体的三维拟稳态流场。引入炭黑在聚合物熔体中的分散数学模型,计算了不同捏合块中炭黑聚集体的粒径分布,比较了3种捏合块流道内炭黑在PE-HD中的分散混合效果。数值结果表明,捏合盘厚度大的捏合块,剪切拉伸作用较强,分散混合能力较强。     

Effect of pitch powder addition on the microstructure and properties of carbon blocks for blast furnace

The phase composition and microstructural evolution of pitch-containing matrix sample with additive of silicon had been compared with pitch-free or resin-containing matrix sample to illustrate the strengthening effect of pitch. Two different pitch powders (CARBORES^@P and High temperature pitch) were then incorporated into carbon blocks, respectively and the effect of pitch powder addition on microstructure and properties of carbon blocks fired at 1000?°C and 1400?°C in a coke bed was evaluated systematically. The results showed that compared with amorphous carbonized resin, carbonized pitch was a kind of highly graphitized carbon and could react with silicon and form SiC whiskers at 1400?°C. In carbon blocks, pitch powder accelerated the formation of AlN at 1000?°C and growth of β-SiC whiskers at 1400?°C, respectively, which enhanced the cold compressive strength, thermal conductivity and hot metal erosion resistance of carbon blocks. Moreover, carbon blocks containing CARBORES^@P pitch with higher carbon yield exhibited better properties because of formation of more ceramic whiskers. The strengthening mechanism of pitch powder for carbon blocks was attributed to the pore-blocking effect of pitch carbonization and more in-situ formed whiskers derived from the reaction between carbonized pitch with silicon at 1400?°C.     

Investigation of heating large blocks of refractory concrete from one side

Conclusions Using the method involving primary heating and cooling of large blocks of refractory concrete, that is, by measuring the pressure of the steam in the concrete and the deformation of the block surface, it is possible to experimentally establish the drying and cooling cycle for blocks of different construction and made from different materials.To prevent the appearance of cracks inside the blocks the rate of raising the temperature should be not more than 10–15deg/hDuring primary heating of blocks more than 20 cm thick, provision should be made for reducing the temperature from 350 to 50–100°C, and for blocks 20cm or less thick provision should be made for a soak at 350°C for a period of 3–5 h.When the temperature of refractory concrete blocks is being reduced, and when they are being cooled, it is necessary to reduce the temperature at a rate of not more than 25–30 deg/h.The verified primary heating cycles for B-2 and B-3 blocks may be used in production conditions.Translated from Ogneupory, No.6, pp.21–26, June, 1967.     

Lining steel tapping apertures of oxygen converters

Conclusions The use of blocks for lining steel discharge apertures substantially reduces the number of repairs, and cuts their work content.The resistance of periclase-spinel blocks and blocks made from brine magnesia is 80–81 heats.The maximum resistance (132 heats) was achieved by using blocks made from fused magnesite.Translated from Ogneupory, No. 7, pp. 5–9, July, 1970.     

制作过程中植生混凝土渗透系数的变化

植生混凝土制作可分多孔混凝土制作、适生材料灌注及植物生长3个阶段.通过制作骨料粒径分别为5～10mm,10～16mm,16～20mm,20～25 mm和25～32 mm的植生混凝土,测定了各阶段渗透系数,探讨了其变化规律.结果表明:在第一阶段,随骨料粒径增大,多孔混凝土的渗透系数依次增大;在第二阶段,适生材料灌注后多孔混凝土渗透系数大幅下降,随骨料粒径变化,多孔混凝土渗透系数的变化规律与灌注前恰恰相反:在第三阶段,16～20mm,20～25mm和25～32mm的多孔混凝土渗透系数随植物生长时间明显增加.所有植生混凝土渗透系数均在0.11 cm/s以上,表现出良好的渗透性;然而,仅骨料粒径为20～25mm和25～32mm的植生混凝土中植物生长状况良好,其可用作环境友好型护岸材料.     

Micelles and networks formed by symmetric triblock copolymers in dilute solutions that are poor solvents for the terminal blocks

Summary A simulation for symmetric triblock copolymers in dilute solution shows a rich variety of structures when the solvent produces a net attractive interaction between the terminal blocks. Depending on the strength of this interaction, the system can form transitory aggregates, large independent micelles, or branched structures in which bridging soluble internal blocks connect dense particles formed by the aggregation of insoluble terminal blocks. The formation of the branched structure with the ABA triblock copolymer can be seen under conditions where the corresponding AB diblock copolymer would provide steric stabilization for a polymer colloid.     

新型节能墙体的动态传热反应系数法分析

利用有限差分法求解新型节能墙体砌块三维温度场和热阻 ,使得计算结果更准确地反映了墙体砌块的静态热工性能。用不稳定传热理论和计算机模拟分析了空心墙体砌块 ,通过比较当量密度法和当量厚度法 ,确定了传热反应系数项数的确定值 ,进一步完善了传热反应系数法 ,为此理论在空心墙体砌块的实际应用创造了更好的条件     

Effects of micelle structures formed in selective solvents on crystallization behaviors of poly(ethylene glycol)-b-poly(styrene) copolymers

Well-defined amphiphilic block copolymers, poly(ethylene glycol) methyl ether-b-poly(styrene) (mPEG-b-PS), in which the PS blocks had different molecular weights, were synthesized by atom transfer radical polymerization (ATRP). Through introduction of selective solvents for the blocks, crystalline and amorphous blocks were self-assembled into different micelle structures in solutions. Atomic force microscopy (AFM) was used to characterize the micelle structures. It was observed that spherical micelles were always formed, whereas lamellar aggregates appeared only in the PS-selective solvent when the molecular weight of the PS block in mPEG-b-PS was low. The crystallizable mPEG blocks were self-assembled into either the core or corona of the micelles formed. The effects of the self-assembled structures on the crystallization behavior of mPEG blocks were then investigated with differential scanning calorimeter (DSC). When the PS molecular weight was much larger than that of mPEG, the result showed that the crystallinity of the mPEG block was lower when mPEG blocks crystallized in the corona than that in the core of the micelles. In this case, when mPEG blocks crystallized in micelle coronae, the micelle core formed by insoluble PS blocks was very big, so mPEG chains had to distribute sparsely in the micelle coronae. It was hard for mPEG chains in one micelle or among different micelles to gather together to crystallize. However, when the PS molecular weight was lower than that of mPEG, the crystallinity of mPEG was higher when the mPEG chains crystallized in the micelle corona, as the core formed by insoluble PS was small and the mPEG chains in the corona were easy to aggregate and crystallize.