新型磁选装置的研制及其应用于分离超贫磁铁矿中的磁性铁

磁性铁是超贫磁铁矿勘查中的基本分析项目之一,为准确测定磁性铁的含量,首先需要实现磁性铁的定量分离。目前常用的手工内磁选法由于所用磁铁的有效磁场强度难以保证,而且受人为操作的影响较大,导致分析结果的重现性差。本文应用50 m L滴定管、电磁铁和三相异步电动机,研制了一种新型磁选装置——电磁式磁性铁分选装置,实现了超贫磁铁矿中磁性铁与非磁性铁的定量分离,结合重铬酸钾容量法建立了超贫磁铁矿中磁性铁的分析方法。在选定的磁选条件下(电流2.5 A,磁选管运动频率40 r/min,磁选时间5 min)分析铁矿石标准物质,磁性铁的测定值与标准值的相对误差小于1.0%;分析采自实际矿区的超贫磁铁矿样品,磁性铁的测定结果与手工内磁选法一致,且相对标准偏差(RSD,n=5)小于1.0%,优于手工内磁选法的精密度。本方法采用的电磁式磁性铁分选装置有效地控制了磁场强度的强弱,避免永磁铁出现磁损失,同时可以量化磁性铁分离的参数,提高了磁性铁的分析精度。

Development of A New Magnetic Separation Device and Its Application in Separation of Magnetic Iron in Ultra-low-grade Magnetite

The content of magnetic iron is one of the basic analyses in ultra-low-grade magnetite exploration. In order to accurately determine the content of magnetic iron, quantitative separation of magnetic iron is very important. There is no standard method for the analysis of magnetic iron in iron ore, and the reproducibility of common artificial magnetic separation is poor due to the human factors and the difficulty of guaranteeing effective magnetic field intensity. A new magnetic separation device (electromagnetic separation device) was developed by using 50 mL burette, electromagnet and a three-phase asynchronous motor. Magnetic iron and nonmagnetic iron in ultra-low-grade magnetite was quantitatively separated by optimizing the working conditions. Determination of magnetic iron was proposed by combining the potassium bichromate titrimetric method with a magnetic separation technique. When the current was 2.5 A, the motion frequency of the magnetic tube was 40 times/min, and the time of magnetic separation was 5 min. The relative error was lower than 1.0% for the reference material. For the practical samples, the analysis results completed by the proposed method were in agreement with those determined by artificial magnetic separation with the RSD of the proposed method being lower than 1.0%, which was an improvement over the precision of artificial magnetic separation. For the new method, the magnetic field intensity was effectively controlled, the parameters for the separation of magnetic iron were quantized, and the measurement accuracy was improved for magnetic iron.