论文部分内容阅读
各种铁矿粉和精矿的造球性能差异很大,适宜的工艺条件必须通过试验来确定,其中首先要确定的是,原料的粒度及粒度组成是否适于造球。实践证明,在一定的粒度范围内,就能满足造球的要求。粒度过粗则生球的落下强度及熟球的转鼓指数差,粒度太细则磨矿费用大,如果是湿磨,过滤困难,且随着精矿的变细球团干燥脱水慢,破裂温度低。造球物料的理想粒度范围,通常用比表面积(厘米2/克)来表示,粒度组成中大于28-35目(0.59-0.42毫米)的比例不能太大。当精矿的布莱恩氏比表面积为1500-1900厘米2/克时,造球性能十分良好,一般不需再磨。天然粉矿虽然原有较高的比表面积,但28-35目的比例最好小于5-10%,对于精矿,特别是磁铁矿精矿,粗粒级应更低,一般是不允许有这样的粗粒级。因此来厂原料,如果粒度不符合要求,还必须进行磨矿。例如日本加古川厂全部是进口铁矿和铁精矿,采取预先分级,干式闭路磨矿,要求-325目占60-80%,比表面积在1500-1900厘米2/克范围之内。当然也有许多球团厂运来的精矿本身就很细,因此不存在磨矿的问题。如美国的铁隧岩,在选矿时就已经细磨。
The pelletizing properties of various iron ore powders and concentrates are very different. Suitable process conditions must be determined through experiments. The first thing to be sure is whether the particle size and particle size of the raw materials are suitable for pelletizing. Practice has proved that in a certain range of particle size, will be able to meet the requirements of the ball. If the particle size is too coarse, the dropping strength of the green ball and the rotating drum index of the cooked ball are poor. If the particle size is too small, the grinding cost is large. If it is a wet mill, the filtration is difficult. low. The ideal particle size range for pelletizing materials, usually expressed in terms of specific surface area (cm 2 / g), should not be greater than 28-35 mesh (0.59-0.42 mm) in the particle size composition. When the concentrate’s Bryon’s specific surface area of 1500-1900 cm 2 / g, the balling performance is very good, generally do not need to re-mill. Although the original high-grade natural ore surface area, but the proportion of 28-35 the best is less than 5-10%, for the concentrate, especially magnetite concentrate, coarse level should be lower, generally not allowed This coarse level. Therefore, raw materials to the plant, if the particle size does not meet the requirements, but also must be grinding. For example, Japan’s Kakogawa plant is all imported iron ore and iron ore concentrate, pre-grading, dry closed-circuit grinding requires -325 mesh accounted for 60-80%, the specific surface area within the range of 1500-1900 cm 2 / g. Of course, there are many pellets shipped by the concentrate itself is very fine, so there is no grinding problem. Such as the United States iron tunnel, mineral processing has been fine grinding.