Research on corrosion mechanism of refractory lining in drip zone of COREX melting gasifier

In this paper, the COREX-3000 melting gasifier was dissected and sampled to obtain the macroscopic erosion appearance of refractories lining in the drip zone, and the erosion behavior and mechanism of refractory bricks in the drip zone were analyzed by means of chemical analysis, XRD, SEM and determination of physical characteristics. The results showed that the maximum average erosion of refractory lining bricks in the drip zone was 220 mm and the erosion rate was up to 69%. Its surface was mainly affected by slag erosion and mechanical scour of slag, but at high temperature, the surface of refractory could be re-sintered, forming a protective layer, which improved the volume density and high compressive strength of refractory, which was advantageous to the improvement of refractory brick slag resistance invasion and mechanical erosion resistance. Relevant research results can provide theoretical basis for the selection of refractories lining in the drip zone of COREX melting gasifier.

Mechanism Research on Melting Loss of Coppery Tuyere Small Sleeve in Blast Furnace

The tuyere small sleeve in blast furnace works under poor conditions. The abnormal damage of it will severely affect the performance of the blast furnace, thus it should be replaced during the damping down period. So it is of great significance that we study and reduce the burnout of tuyere small sleeve. Melting loss is one case of its burnout. This paper studied the reasons of tuyere small sleeve’s melting loss, through computational simulation and microscopic analysis of the melting section. The research shows that the temperature of coppery tuyere small sleeve is well distributed when there is no limescale in the lumen, and the temperature increases with the thickness of limescale. In addition, the interruption of circulating water does great harm to the tuyere small sleeve. The melting loss of tuyere small sleeve is caused by iron-slag erosion, with the occurrence of the melt metallurgical bonding and diffusion metallurgical combination.

Effect of Urban Domestic Wastes on Refractory for Cement Rotary Kiln

The experiment proved the effect of burning urban domestic wastes on alkali-resistant bricks and spalling-resistant high alumina bricks by the Static crucible method. The result indicates that the main erosion mechanism is slag permeable and slag erosion. Burning the waste will emit high temperature gases containing alkali, sulfur and chlorine, and the gases react with refractory materials contribute to the formation of sulfate, chloride and compound salt, which deteriorate and invalid refractory gradually. Through SEM, it is observed that the loose structure of metamorphic layers and easily spalled during thermal stress.

Application of Reclaimed Ladle Bricks in Magnesium Aluminate Spinel Based Castables

The way of producing ladle used MgO-Al2O3 castables using reclaimed bricks of ladle as aggregate is researched by structure analysis, XRD and phase diagram analysis. Influence on structure and physical properties of castables added different percentage of reclaimed bricks is discussed. The following conclusions are got: Adding suitable reclaimed ladle bricks won’t decrease the strength of the specimens, all the specimens have high bulk density(≥2.98g/cm3) and low apparent porosity(≤14%); Suitable addition of reclaimed ladle bricks as aggregate can improve the thermal shock resistance of MgO-Al2O3 castables, however, over-addition will weaken its thermal shock resitance; Slag erosion resistance increases with the addition of reclaimed ladle bricks. To sum up, reclaimed ladle bricks can be used in MgO-Al2O3 castables and castables with excellent comprehensive properties can be got when 12.5% reclaimed ladle bricks are added as aggregate.

Effect of Ladle Slag Modification on Slag Sticking to Snorkel and Rate of Slag Erosion

To reduce the slag sticking to snorkel and to increase the operation life of snorkel during ladle alloying process, B2O3-CaO (mass ratio 1:2) and CaF2-CaO(mass ratio 1:2) were respectively employed as modifiers added to ladle slag. The effects of modifier on weight of sticking slag and erosion rate were investigated. The results showed that the weight of slag sticking to snorkel is reduced, but the rate of modified ladle slag pervading into snorkel is increased with the increasing of modifier added into ladle slag. The optimal weight of modifier is about 10 percent of total weight of ladle slag. The results of test in practice indicate that the slag sticking to the snorkel has been reduced by the slag modification. At the same time, the industrial applied test results show that the operation life of snorkel is increased by more than 100 percent.

Corrosion Behavior of BF Slag to SiAlON Bonded Corundum Refractories

The corrosion behavior of BF slag to sialon bonded corundum refractories using reaction nitriding technology at 1500°C was investigated by crucible test method. The results show that the reaction products of slag corrosion are anorthite, magnalium-spinel and glass phases. The corundum grains can react with MgO in the slag to produce magnalium-spinel, accompanying by expansion and liquating stepwise by slag. Erosion mechanism is oxidation-erosion-dissolving. This study is very necessary and useful to improve the property of BF slag resistance and to yield better overall properties of sialon bonded corundum refractories.