瑞典馬姆貝格特(Malmberget)和基魯那(Kiruna)选矿厂的筛分作业有两个任务。其一是将矿石筛分成为三种粒級,以便送往各种型式的磁选机进行处理。这就要求一定要从較粗的粒級中尽可能脫除矿泥,否則就会严重地影响磁选。另一任务是要在一定情况下筛分出适于Dwight-Lloyd烧結法的細粒产品。为了用于式筛分分出这种細的矿石,人們用一种所謂L-筛代替了用了几年的共振筛。这种L-筛的筛面是圓輥,筛輥安装在傾斜的筛框两侧壁中間的钻孔內(图1)。筛子的上端 Sieving operations at the concentrators in Malmberget and Kiruna in Sweden have two tasks. One is to screen the ore into three particle sizes for delivery to various types of magnetic separators for processing. This requires that the slime be removed as much as possible from the coarser grain size, otherwise it will seriously affect the magnetic separation. Another task is to screen out the fine-grained products suitable for Dwight-Lloyd sintering under certain conditions. In order to classify this fine ore by sieving, people used a so-called L-sieve instead of using the resonant sieve for several years. The screen of this L-screen is a round roll with screen rolls installed in the holes in the middle of the two side walls of the sloping screen frame (Figure 1). The top of the sieve