焦宝石基可塑料的研制

以焦宝石、叶蜡石和黏土为原料制备了焦宝石基可塑料,对比分析了焦宝石基可塑料与铝矾土基可塑料的物理性能,结果表明:焦宝石基可塑料的物理性能略低于铝矾土基可塑料的物理性能,但是该可塑料成本较低,可部分替代铝矾土基可塑料应用于加热炉的低温段炉顶部位和烟道部位,使用效果良好.     

Vibrogrinding and washing commercial alumina

Conclusions The temperature of precalcination of commercial alumina for manufacturing corundum ceramics should not exceed 1550°C. In this case fine grinding of calcined alumina can be successfully done in a short period in a vibromill by the dry method.The advantage of the dry method of vibrogrinding is the substantial reduction, compared with the wet method, of iron pickup, and consequently the abrasion of the balls and the linings, and also the consumption of hydrochloric acid.Calcined commercial alumina ground dry is effectively washed to get rid of impurities compared with ground material using the wet method; in the washed dry ground alumina the content of Na₂O is less by a factor of 4–7 than in the wet ground, and the content of Al₂O₃ is higher by 0.15%.From commercial alumina type G-00 according to GOST 6912-54 it is possible to obtain finely ground calcined alumina containing more than 99.9% Al₂O₃ and 0.020% Na₂O. Together with this the use for the preparation of densely sintered corundum ceramics of dry ground vibromilled alumina is more effective than for wet milled [16].     

Modelling of fused cast alumina refractory

Abstract

Finite difference computer modelling of a 2D cast mould insulation annealing system (CMIA) was used to investigate the temperature gradient and thermal stress distribution during cooling of a fused cast α,β-Al₂O₃ refractory. It was found that, of the various materials comprising the system, the mould material has the largest influence on the temperature gradient and thermal stress distribution, particularly at the beginning of cooling. The insulation layer has a large influence over the whole cooling cycle. The influence of the annealing layer mainly occurs in the later stage of cooling. As the thermal conductivity of any layer in the CMIA system increases, the peak temperature gradient and peak thermal stress in the cast increase rapidly, and move to a lower temperature region. This is obvious in the case where all the layers except the cast are of the same material. As the thermal conductivity of the mould in the cast mould system increases, the peak temperature gradient increases rapidly and moves to a lower temperature region until a maximum occurs at about 1310°C. The largest temperature gradient and thermal stress, therefore, appear in the temperature range 1310 to 1580°C for cooling fused cast α,β-Al₂O₃ refractory. An optimum thickness exists for any layer in the CMIA system to give minimum temperature gradient and thermal stress. Deviation from the optimum thickness leads to proportionate increases in the temperature gradient and thermal stress. In addition, optimum thicknesses are related to each other, and also to the size of the cast. This is also obvious in the case where the system, except for the cast, consists of the same material. The temperature gradient is proportional to (x_r /d_x )(y_{r r} /d_y ) for a cast mould system. A second peak in temperature gradient, in addition to a major peak in the high temperature region, appears below 1580°C, and is closely related to the thickness of each layer in the system. The second peak can be eliminated if the thickness of each layer in the system is optimum, and its elimination would decrease the possibility of cracks forming in the cast.     

Utilisation of South Libyan clay for preparation of mullite-alumina based refractory ceramics

Abstract

This work aims to benefit from the wide spreaded clay in south Libya with some alumina (Al₂O₃) additions to prepare and characterise mullite-alumina containing refractory ceramics. The starting materials used in this investigation are local raw clay and chemical aluminium oxide (Al₂O₃). Based on a previous geological survey carried out by the industrial research centre (Tripoli), four different clay samples were selected from different locations of the south of Libya. Representative samples of the four selected clays were investigated using X-ray diffraction (XRD) and differential thermal analysis. The four clay samples were used separately together with aluminium oxide to prepare six different batches containing different proportions of alumina from 0 up to 60% with an increament of 10%. The mullite containing bodies were investigated through their mineralogical compositions using XRD and scanning electron microscopy (SEM) attached with energy dispersive X-ray unit (EDX). The sintering, mechanical and refractory properties of the prepared mullite containing bodies were tested according to the international standard specifications. It is concluded that the densification, mechanical and refractory properties are improved as the alumina content increases on the expense of clay. Mixes containing 60% clay : 40% alumina and 50% clay : 50% alumina respectively, especially those prepared from Agar clay are characterised with good sintering, high mechanical and high refractory properties.     

Plastic molding refractory mixes based on highly concentrated ceramic binding suspensions of high alumina fireclay

Refractory mixes of high alumina composition are developed for plastic molding. The mixes are distinguished from more traditional ones by a low clay content (by a factor of 3–5) due to introduction into the mix composition of highly concentrated ceramic binding suspension based on high alumina fireclay that promotes an improvement in the basic physicomechanical properties of articles made from these mixes. __________ Translated from Novye Ogneupory, No. 3, pp. 120–125, March, 2007.     

粘土结合耐火浇注料的研制

选用山东特级焦宝石、贵州焦宝石、河南三级高铝矾土熟料和山西阳泉特级高铝矾土熟料为骨料 ,河南三级高铝矾土熟料和山西阳泉特级高铝矾土熟料的球磨粉为基质 ,广西软质粘土为结合粘土 ,三聚磷酸钠、六偏磷酸钠、柠檬酸钠、酒石酸钠、酒石酸钾钠、碳酸钠 6种钠盐作分散剂 ,铝 60高铝水泥作促凝剂 ,配制了 4种不同组成的粘土结合耐火浇注料。在试验研究的基础上 ,分析了不同分散剂对广西软质粘土的分散效果 ,分散剂在粘土 -水体系中的分散机理和不同骨料对粘土结合耐火浇注料性能的影响。结果表明 :分散剂的分散效果以六偏磷酸钠为最好 ;以广西软质粘土作结合剂 ,用烧结良好的特级高铝矾土熟料作耐火骨料研制的粘土结合耐火浇注料 ,用水量少 ,气孔率低 ,结构致密 ,强度高     

Prospective equipment for winning refractory clay and kaolin

Conclusions The requirements of the establishments of the Ukrainian Refractories and Ore Association for bucket-wheel excavators can be satisfied with the ÉR-315 and ÉR-630 types. The first of these include the excavators ÉRG-120 12/0.8 and SRs-240 9.5/0.5. In the design specifications for bucket-wheel excavators for operations at the face, account must be taken of the special features of the technological process, the principal one being that the lumps of the excavated material are of the required size and that the machine remains stable and efficient without loss of extracted material when working seam sections with a dip of up to 8°.Translated from Ogneupory, No. 7, pp. 23–26, July, 1978.     

Sintering of fireclay-kaolin mixtures with refractory clay

It is shown that the sintering of fireclay-kaolin mixtures is intensified by the replacement of refractory easily sintering plastic clays by high-melting clay. Recommendations are given on the choice of the method for preparation and introduction of the mentioned additive into the mixture. The developed technology has been tested under industrial conditions. Translated from Steklo i Keramika, No. 6, pp. 25 – 27, June, 2000.     

低铝粘土在卫生陶瓷生产中的应用

新疆地区粘土资源普遍含铝量低、含硅量高。为了提高企业的竞争能力 ,充分发挥本地资源优势 ,我厂于 1999年 4月实施技改。技改期间 ,在实验室里进行利用低铝粘土生产卫生陶瓷的配方实验。经半年时间的原料调查及配方试验 ,于当年 10月投产 ,经 2年多的生产实践证明完全可行。1　试验与结果1.1　原料的选择及化学成分要生产高档卫生陶瓷 ,泥浆的容重就要高 ,为了达到生产所需的容重 ,在确定配方前应对原料进行有条件的选取。选取原料的原则是 :首先在满足原料化学成分要求下 ,根据原料的解胶性能对原料进行择优劣汰。选取粘土原料的要求是 :…