【摘要】 本文叙述了焙烧温度、碱度、气体湿度和球团粒度对去氟反应的影响以及热力学和动力学计算分析的结果。在所试验的精矿中全氟量的80-90％是以萤石（CaF₂）状态存在,而10-20％是以氟碳铈矿和氟碳钙铈矿存在。氟碳铈矿和氟碳钙铈矿在570—660℃温度范围内开始分解放出F₂。虽然萤石是稳定化合物,但是在提高焙烧温度和在空气中加入水分的条件下,可以除去70—80％ 的 F₂。提高碱度可以减少CaF₂的分解,但球团强度将降低。 根据试验结果,去氟反应的表观活化能分别是 44600 Cal/mol（有水反应）和 7400 Cal/mol（无水反应）。反应速度常数（k）与温度（T°k）间的关系是 对于有水反应的条件 lg k=-9750/T+5.59 对于无水反应的条件 lgk=-1616/T-1.1432。 焙烧的结果,球团中约有30％K₂O和7—14%Na₂O被除去。 提出了一些防止氟污染的措施,如降低精矿含氟量,改善焙烧机的密封和调整焙烧机上的气流方向等。更多还原

【Abstract】 This paper describes the effects of such conditions as roasting temperature, basicity, moisture content in air and pellet size on the defluorination reaction under roast of iron pellets containing fluorine. Calculations and analyses has been given thermodynamically and kinematically. While about 70-80% of total fluorine in tested concentrates is presenting in the form of fluorite (CaF2), the remainder is taking the forms of bastnaesite(Ce·La·Dy)FCO3 and parisite Ca(Ce·La)2(CO3)2F2. Bastnaesites and parishes begin to dissociate in the temperature range 570℃ to 660℃, thus giving F2 out in gaseous state. The compound CaF2, although in higher stability, about 70-80% of total fluorine can be removed from it provided that the roasting temperature be increased. In addition,increase of moisture content in air is also properly beneficial to defluorination. As for increase of pellet’s basicity, to be sure, the decomposition of CaF2 will be probably limited but its strength decreased.Based on experimental data, the apparent activation energy for defluori-nation reaction has been determined equal to 44,600 cal/mol (with H2O) and7,400 cal/mol (without H2O) respectively. The relation between reactionrate constant k and temperature T°K are given as follows: with H2O,lgk=9750/T+5.59;without H2O,lgk=1616/T-1.1432.As a consequence of roasting, about 30% of K2O and 7-14% of Na2O in pellets may be removed.Some proposals are put forward here that the measures should be adopted to prevent the atmosphere pollution by fluorine, such as the decrease of fluorine content in iron concentrates, the improvement of real conditions in induration machine and the regulation of gas flow etc.更多还原