Experiment Research On Taphole Clay Erosion By Slag Containing Alkalis

With the falling profits of the iron and steel industry,reducing the production cost is becoming more important for the enterprise.Apart from concerning the main raw materials,such as iron ore,Some auxiliary raw material should be concerned as well,such as taphole clay,which is a kind of plastic refractory and used to plug iron notch.Compared with other similarly domestic blast furnace,taphole clay consumption has been high in a northwestern blast furnace.If the consumption of taphole clay can be reduced,the production cost will be reduced and the competitiveness of the enterprises will be mentioned.Comparing the composition of slag in this blast furnace with other domestic slag,the slag contains too much K and Na,which are alkalis.We infer alkalis may be the reason that the consumption of taphole clay is very high.Therefore,this research will be carried out.This essay adopts immersed rotating experiment method.Firstly,the research compared the erosion amount and the erosion thickness of transition layer of taphole clay,which are in different conditions.Respectively,the taphole clay was immersed in ordinary slag and slag whose alkalis content is 2%and the taphole clay is static in the slag and rotates in 120r/min.The main reason of taphole clay erosion was analyzed.Secondly,this essay discussed the impact of taphole clayerosion amount,which are the composition of slag and the sintering conditions of taphole clay;It analyzed the microstructure and composition of the eroded taphole clay sample and put forward the mechanism how slag containing alkalis erodes taphole clay.The main conclusions as follows:(1)Ordinary blast furnace slag and slag containing alkalis have effect on the erosion of taphole clay,and the later is more serious than the former;Scour can exacerbate the erosion of taphole clay,and the slag containing alkalis is more obvious than ordinary slag.(2)Because of the erosion of alkalis slag,the taphole clay has two layers,which are respectively the erosion transition layer and hypostasis layer.The structure of erosion transition layer of the taphole clay was damaged.Some low melting point compounds were generated inside and gradually dissolved in the slag.Some slag compositions gradually reduce from inner to outer and they permeate to the taphole clay constantly.(3)With the increasing of alkalis content,the erosion amount and thickness of erosion transition layer of taphole clay is more and more bigger.When the basicity is 1.05 and the alkalis content is 0%,2%and 4%respectively,the erosion amount of taphole clay is 0.231mm,0.407mm and 0.528mm.The latter is 1.76 times and 1.30 times than the former respectively.When the basicity is 1.15 and the alkalis content respectively is 0%,2%and 4%,the erosion amount of taphole clay is 0.127mm,0.293mm and 0.440mm.The latter is 2.3 times and 1.50 times than the former respectively.Therefore,with the increasing of alkalis content,the erosion amount of taphole clay is more and more bigger.When the alkalis content respectively is 0%,2%and 4%and the basicity is 1.05,the erosion amount and thickness of erosion transition layer of taphole clay are bigger than the one whose basicity is 1.15.The former is 0.104mm,0.114mm and 0.088mm more than the latter and is 1.81 times,1.39 times and 1.20 times than the latter respectively.(4)With the reducing of sintering temperature and sintering time,the erosion amount of taphole clay increased greatly.When the alkalis content is 0%,2%and 4%respectively,the erosion amount of taphole clay whose sintering temperature is 1200 ? is 0.082mm,0.247mm and 0.266mm more than the one whose sintering temperature is 1400 ? respectively,and the former is 1.64 times,1.84 times and 1.60 times than the latter.When the basicity is 1.15 and the alkalis content is 0%,2%and 4%respectively,the erosion amount of taphole clay whose sintering time is 1h is 0.203mm,0.364mm and 0.687mm more than the one whose sintering time is 1400 ? respectively,and the former is 2.60 times,2.24 times and 2.56 times than the latter.The sintering time of taphole clay has great effect on the erosion amount.(5)The erosion process of taphole clay slag containing alkalis,the ground mass of taphole caly forms crack and hole when the taphole clay sinters,whose binder volatilize;When the slag containing alkalis contact with the taphole clay,it can permeate the taphole clay inside by the crack and hole;The composition of slag react with taphole clay and generate low temperature compounds;The surface layer was destroyed and dissolved in the slag and the reaction interface put forward the inner of taphole clay.