【正文】
固體物料分選學(xué) Solid materials processing 第一篇 選前準備 Ore Preparation 選前準備 Ore Preparation ( 1)作用: 選前準備是對固體物料進行有效分選的首要前提。 ? 使物料中的不同組分彼此解離; ? 為選別作業(yè)提供適宜的給料粒度。 ( 2)組成: ? 破碎、篩分; ? 磨碎、分級。 ( 3)重要技術(shù)指標: ? 給料和產(chǎn)品的粒度組成。 1 物料的粒度組成及分析 Particle size distribution size analysis for material ? 粒度組成及粒度分析 Particle size distribution size analysis ? 篩分分析 Sieve analysis ? 粒度特性方程 Mathematical representation (The equations of particlesize distribution) 粒度組成及粒度分析 Particle size distribution Size analysis ? 粒度及其表示方法 Particle size and its presentation methods ? 粒度分析方法 Size analysis methods (particle size measuring methods) 粒度及其表示方法 Particle size and its presentation methods ? 粉碎、磨碎和分選過程所處理的物料,都是尺寸大小不一、形狀各式各樣的松散粒群。對于這類松散物料,技術(shù)上通常引入“粒度”、“粒級”、“粒度組成”及“平均粒度”來描述粒群的特征。 粒度 Particle size ? 顆?;蛄W哟笮〉牧慷?。表明物料粉碎的程度,一般用 mm(或 μm)表示。 ? 在實際工作中,粒度通常借用“直徑”一詞來表示,記為 d。 ? 表示單顆粒的粒度。 平均直徑計算公式: d=(a+b+c)/3 ? The exact size of an irregular particles cannot be measured. The terms length, breadth, thickness, or diameter have little meaning because so many different values of these quantities can be determined. The size of a spherical particle is uniquely defined by its diameter. For a cube, the length along one edge is characteristic, and for other regular shapes there are equally appropriate dimensions. ? 不規(guī)則顆粒的精確粒度是不能測定的,長、寬、厚度或直徑之類的量詞都沒有多大的意義,因為對這些量都可以測出許多不同的數(shù)值。球形顆粒粒度的唯一定義是它的直徑;立方體的特征尺寸是它一邊的長度;而對其他的規(guī)則形狀顆粒也同樣有合適的量度。 ? For irregular particles, it is desirable to quote the size of a particle in terms of a single quantity, and the expression most often used is the “ equivalent diameter” . This refers to the diameter of a sphere that would behave in the same manner as the particle when submitted to some specified operation. ? 對于不規(guī)則顆粒,最好用單一的量表示顆粒的大小,常用的表示方法是“等效直徑”。這是指在某一特定過程中能發(fā)生與該顆粒相同的行為的球體的直徑。 ? The equivalent diameters usually depends on the method of measurement. Several equivalent diameters are monly encountered. For example, the Stokes180。 diameter is measured by sedimentation and elutriation techniques。 the projected area diameter is measured microscopically and the sieveaperture diameter is measured by means of sieving. ? 等效直徑往往因測量方法而異。常見的等效直徑有幾種,例如,通過沉降和淘析技術(shù)測定的斯托克斯直徑 (p208),用顯微鏡測定的投影面積直徑以及通過篩分確定的篩孔直徑等。 粒級 size range ? 用某種方法(如篩分)將粒度范圍較寬的碎散物料粒群分成粒度范圍較窄的若干個級別,這些級別