Feedstock K, Effects Of Na, Pb, Zn Maintenance Of Blast Furnace

In recent years, the blast furnace intensified smelting is realized, so the life of the blast furnace became an important technical index, long service life of blast furnace is very important to reduce production costs, improve the economic and technical index, ensure safety in production, so the study of blast furnace maintenance is very significant.The effective volume of No.3BF in an iron and steel company is1350m3, the harmful elements of raw materials increased since the beginning of last year because of using the local iron ore. In order to study the effect of K, Na, Pb, Zn on the blast furnace maintenance and find effective control means, in this paper, the effect of harmful elements on the rise of furnace body, tuyeres tilting upwards and hearth erosion is analyzed by using statistics, field measurement, erosion model, data comparison and so on. Then the corresponding measures are put forward based on the harmful element erosion theory and previous experience in production.In this paper, I summarize the enrichment and harm principle of harmful elements in BF starting from the practical problems, discuss the purpose and necessity of this subject on the basis of recent research on the harmful elements.In this paper, I collect the quantity and laboratory data of materials of No.3BF during2011-2012, calculate the K, Na, Pb, Zn load, the proportion of income and expenditure and the material balance, find the main way of income and expenditure of the harmful elements, analyse the methods of reducing the intake of harmful elements and improving the discharge rate.On the basis of summarizing the longitudinal distribution of harmful elements in blast furnace and the force analysis of furnace body rise, I compare harmful elements load with the furnace body rise curve, and then find that the lead which enriched in the hearth bottom is a main factor for causing the furnace body rise.I arrange the tuyeres tilting upwards data and draws the curve of tuyere average offset. I find that alkali metals and zinc are the main factors of causing expansion of tuyere brick and the tuyeres tilting upwards based on the analysis of enrichment of harmful elements and the comparison between harmful elements load and tuyere average offset.In this paper, I establish the erosion model by the heat conduction differential equation and calculate the speed of the erosion over the last two years based on the statistics of the temperature data of the thermocouples of3#BF in last two years. I analyse the mechanism of harmful element eroding the refractory, compare the erosion speed with the curve of harmful elements load, then I find that hearth and bottom erosion speeds with the load increase of harmful elements.According to the influence of the harmful elements on furnace maintenance, I put forward some methods to prolong the life of blast furnace such as controling the source of harmful elements, improving discharge rate, stengthening the operation and maintenance, and provide a reference for future operation.