杂卤石矿地浸模拟实验研究

LABORATORIAL STUDY ON THE LEACHING PROCESS OF POLYHALITE

通过对难溶含钾矿物杂卤石的柱浸实验模拟石溶浸过程分析发现,采用CaCl2溶液作溶浸剂,其溶浸剂浓度、淋洗速度、矿石粒度、浸滤路径等因素对K溶浸率及溶浸速度均有影响,当矿石粒度为1 mm和5 mm时,钾浸出率分别可达到80%和70%以上,溶浸剂浓度增加,可提高钾的浸出率,但CaCl2浓度高于5%后,效果不明显。淋洗速度增大,虽可提高钾的浸出率,但同时浸出液中钾的富集程度有所降低,以4.5 ml/h～10 ml/h为佳;增加渗滤路径长度可同时提高钾的浸出率和富集程度。实验结果表明杂卤石溶解过程受固相层扩散控制,溶解反应过程较好地符合“收缩未反应核模型”的固相控制动力学方程1-(2/3)α(1-α)2/3=(2MD′c/bργ02)t。研究结果为地浸开采深埋藏杂卤石提供了一定的实验基础。

This paper presents a fundamental study of new method of exploiting potassium from polyhalite deeply buried underground in Sichuan Nongle. The kinetic process of leaching potassium from polyhalite is studied by investigating the influence of the leaching conditions, such as concentration of lixiviant （CaCl2）,granularity of mineral,velocity of solution flow and the length of mineral,on the process of lixiviation through analysing potassium concentration in the lixiviating solution. The experiment results show that the recovery of K from polyhalite under the condition can be over 80% and 70% respectively when the particle sizes of ore are lmm and 5mm. The macroscopic reaction dynamics of lixviation of polyhalite in CaCl2 solution was studied on the basis of heterogeneous-phase reaction dynamic principle and the experimental data. The lixiviation procedure is controlled by solid bedding diffusion and suits to ＂Contraction Non-Action Nuclear Model＂ and the equation, 1- （2/3）α- （1- α）2/3 = （2MD＇c/bργ0^2）t.