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

    精确重量50±0.1g样品筛,轻轻用手指粉碎质量,覆盖了筛板筛盖和盖,和操作按照下列方法:把筛在一方面,稍微倾斜,震动筛,使其达到另一方面,震动速度是每分钟125次,筛摆的幅度大约是20厘米。筛应该旋转90度角在一定方向每25次均匀扩散样品(机械振动方法还可用于筛选),直到经过筛样品的数量在1分钟内小于0.1克,和材料的质量筛(筛余物)重0.01克。

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

    筛余量计算公式为:C=B/A×100%

    Thecalculationformulaofscreenallowanceis:C=B/a×100%

    式中:C——筛余，%;

    Where:C--sieveresidue,%;

    B——屏幕上材料的质量，以克(g)为单位;

    B-massofthematerialonthescreen,ingrams(g);

    A-样品的原始质量(克);

    A-originalmassofsample(g);

    如果一个石膏粉不知道细度(网),前组可以使用屏幕(如80目,100目,120目,140目,160目,180目,等等),筛分机械振动方法,测试每个筛筛余量,确定济南石膏粉细度(网)多少,也能反映石膏粉的细度(谷物)分布。

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