Dryabout60gofthesampletobetestedintheelectricblastdryingoventoaconstantweightof40±4℃,andthenputthedrysampleintothedryerforcoolingforlateruse(Note:whenthedifferencebetweenthetwoweightsisnotmorethan±0.2g,thisistheconstantweight).

    精確重量50±0.1g樣品篩,輕輕用手指粉碎質量,覆蓋了篩板篩蓋和蓋,和操作按照下列方法:把篩在一方面,稍微傾斜,震動篩,使其達到另一方面,震動速度是每分鐘125次,篩擺的幅度大約是20厘米。篩應該旋轉90度角在一定方向每25次均勻擴散樣品(機械振動方法還可用于篩選),直到經過篩樣品的數量在1分鐘內小于0.1克,和材料的質量篩(篩余物)重0.01克。

 Accurateweight50±0.1gsamplesieve,lightlycrushthemasswithfingers,coverthesieveplatecoverandcover,andoperateaccordingtothefollowingmethods:ontheonehand,tiltthesieveslightly,shakethesievetoreachtheotherhand,thevibrationspeedis125timesperminute,andtheamplitudeofsieveswingisabout20cm.Thesieveshallrotate90degreestoevenlyspreadthesampleinacertaindirectionevery25times(mechanicalvibrationmethodcanalsobeusedforscreening),untilthenumberofsamplespassingthesieveislessthan0.1ginoneminute,andthemasssieve(residue)ofthematerialweighs0.01g.

    篩余量計算公式為:C=B/A×100%

    Thecalculationformulaofscreenallowanceis:C=B/a×100%

    式中:C——篩余，%;

    Where:C--sieveresidue,%;

    B——屏幕上材料的質量，以克(g)為單位;

    B-massofthematerialonthescreen,ingrams(g);

    A-樣品的原始質量(克);

    A-originalmassofsample(g);

    如果一個石膏粉不知道細度(網),前組可以使用屏幕(如80目,100目,120目,140目,160目,180目,等等),篩分機械振動方法,測試每個篩篩余量,確定濟南石膏粉細度(網)多少,也能反映石膏粉的細度(谷物)分布。

 Ifagypsumpowderdoesnotknowthefineness(mesh),thescreen(suchas80mesh,100mesh,120mesh,140mesh,160mesh,180mesh,etc.)canbeusedinthefrontgrouptoscreenthemechanicalvibrationmethod,testeachsievemargin,determinethefineness(mesh)ofJinangypsumpowder,andalsoreflectthefineness(grain)distributionofgypsumpowder.