Research And Application On The Refractories Castable Of The Desulphuration Injection Lance

In the face of the lower life of the desulphuration injection lance in Chongqing Steel&Iron Co., Ltd, it affects greatly the ability of molten iron sweetening treatment and wastes seriously refractories. Thus, industrial production and experimental research are brought forward. Firstly, operational environment and broken-down cause of the lance is firstly-hand investigated on the spot, and that improvement scheme of castable used for which is devised, which studied the key component of the castable that effected on its properties and optimized the content; then check empirical analysis, which analyzed the cause of the broken-down ; at last industry trial is carried.By means of XRD,polarizing microscope,phase diagram,Materials studio for materials study and imitation, the results show as below:1. Adding Al2O3 powder and heterogeneous SiO2 powder help to sinter; the higher purity of the amorphous SiO2 powder, the more of the mullite forming.2. Sintering property greatly increases when the average diameter of adding spinel was crushed to 1μm ; slag permeability greatly decreases when Al2O3/MgO is 75/25, the average diameter is 1μm ;3. Ductility and impact resilience of the samples are higher with increasing the content and length of the steel fiber in the common and low water concrete castable, the latter is better ; optimization dosage of steel fiber used for refractory castable is 1%～1.5%.4. The thermal shock resistant properties of the improved samples are increased , the average life of slag-line samples is average 52 times; the average life of non-slag-line samples is average 61 times; which compared to the properties of the samples before improved, average 33 times. The property is poor because volumetric expansion gives birth to crack during instable phase shifting to stable phase in refractories, then stress makes crack broaden due to repeated temperature gradient .5. Average erosion depth of the improved samples is 1.11mm, erosion surface is 189mm2; whereas before improved, average erosion depth of the ones is 2.83mm, erosion surface is 260mm2. The reason is that physical chemistry reaction take place when slag immerge into the refractories, low melting reagents including CAS2,C2AS,KAS2,KAS6 increase liquid phase, moreover volume change leads the refractories to scale off. 6. Some vitreous body that binding the lance head is formed on the suface of the refractories when the temperature is lower during scaffolding study, which result in perforation under high pressure gas.According to improved desulphurization injecting lance, industry trial test are carried in the fourth blast furnace of Chongqing Steel&Iron Co., Ltd. The result shows that process life increases from about 30 times to 52 times, process time increases from 212.2min to 498.6min. Therefore, it enhances the ability of the sweetener treatment and reduces production costs, which takes on good economic efficiency.