Using Iraqi materials to produce lining refractories with international standards
In this study dense high alumina refractories were manufactured according to DIN51053 standards and characterizations (physical, mechanical, and thermal) of fired specimens were investigated. The mixtures of specimens were prepared from different weight percentages of (kaolinite, bauxite with additives of alumina to all mixture ratio). The aims of this study was to benefit of local raw materials to produced high alumina refractory characterized by low porosity, in addition to manufacture thermal insulation to use as lining in different industrial furnaces, and enhance the thermal insulation, thermal stability, and mechanical properties of high alumina refractory by adding alumina. From the results it have been obtained high alumina refractory with high compressive strength, high thermal stability, and thermal insulation also have characterized by low porosities and high bulk density.
Characterizations of Semi-Silica Refractory Bricks Produced from Local Iraqi Materials
This research was carried out to investigate the suitability of locally white sand and Dwaikhla clay (Kaolin) for manufacture of semi-silica refractory bricks as thermal insulators for lining the furnaces. Preliminary investigations had been done to determine the physical, chemical, thermal and mechanical properties with mineralogical constitution of raw materials by XRD analysis. Different amounts of kaolinite were added as binder to the white sand (raw materials) of semi-silica bricks. The specimens molded according to DIN standards by using semi-dry pressing method at pressure of (24.516MPa) according to the DIN1068 standards. After drying process at 110°C the specimens fired at firing temperatures (1000, 1100, 1200, 1300 and 1400) °C. The fired specimens have been investigated to determination the physical properties including bulk density, porosity, and the mechanical properties including compressive strength and thermal properties including thermal conductivity. It has been observed from the results that local white sand and kaolinite could be used as possible source raw materials for manufacture semi-silica refractories, mainly required for glass, ceramics factory in Rammadi.
Dense mullite from attrition milled kyanite and α-alumina
Effects of attrition milling on the decomposition of kyanite (Al2SiO5) and its reaction with α-alumina (Al2O3) to form stoichiometric mullite (3Al2O3·2SiO2) are reported. Kyanite-alumina mixes were attrition milled for times from 1 h to 12 h. With increasing milling time, the kyanite decomposition was accelerated and secondary mullite formation from the reaction between the rejected silica and the added alumina was enhanced. Milling reduced the decomposition expansion from +15.0% to +0.1% and the final contraction or densification from +2.5% to −13.7%. During firing complete mullite formation occurred after firing at only 1623 K/1h (1350C/1 h) to produce a dense mullite ceramic with a fine grain size (~1 μm).