The Research Of Coke Reaction Beginning Temperature And Its Influential Factors

Along with the advance of iron-making technology,the function and behavior of coke in blast furnace are being cognized profoundly and more requirements for coke are put forward.Many scholars hold that the quality indexes of coke should include the reaction beginning temperature except coke reactivity index and coke strength after reaction in order to simulate better coke degradation in blast furnace.Coke reaction beginning temperature is the temperature at which coke start reaction with carbon dioxide(CO2).It is dividing-line temperature of indirect reduction and direct reduction of iron oxides in blast furnace,and associates with thermal reserve zone of blast furnace and affects FeO-Fe reduction equilibrium point(W point)in blast furnace,therefore changes consumption of reducing agent and availability of blast furnace gas.A determination method of coke reaction beginning temperature is developed and defines the temperature at which concentration of carbon monoxide produced rise to 1% as the coke reaction beginning temperature.The effect of coal charge properties,technological parameters and additives on coke reaction beginning temperature is studied systematically.The results show that there is an obvious influence of coal charge property on coke reaction beginning temperature:along with coalification degree increase,the reaction beginning temperature of single coal coke increase,and reaction beginning temperature of coal blend coke increase with increase of caking index and decrease of volatile content;there is a little effect of bulk density of coal charge on coke reaction beginning temperature;there is certain influence of fineness of coal charge on coke reaction beginning temperature:coke reaction beginning temperature increase and the then decrease,a maximum value present at 90% of fineness;there is very obvious influence of additives on coke reaction beginning temperature,both iron ore powder and calcium hydroxide,the coke reaction beginning temperature declines sharply with increase of additive ratio.The coke reaction beginning temperature relates with coke reactivity: their relation shows negative correlation,and under certain circumstance their relationship is of uncertainty,for example,under the condition that fineness of coal charge changes,the reason needs to be studied intensively.