摘要
商业交易的装运铁矿石取样应当按照ISO 3082进行。尽管近年来合规性已有所改善,但在一些方面仍存在明显问题,包括:1)大流量样品截取器的设计和操作;2)在二级取样阶段对一级增量样品的划分;3)缩分之前用于减小样品粒度的破碎机的破碎性能;4)在每个取样阶段保留的样品质量;5)样品缩分。取样是测量过程开始的地方,因此如果样品不具有代表性,整个过程在开始时就被破坏了。正确取样的“金规则”是“被取样物料的所有部分都必须有相等的概率被收集到并成为最终分析样品的一部分”。如果不遵守这一规则,那么就很容易引入偏差。例如,在实践中不可能从库存料堆或船舶现场采集到具有代表性的样品。必须在构建堆料或分解堆料时,或在船舶的装载或卸载时取样。在满足“正确取样的金规则”后,取样站设计还应符合以下要求:1)采集的样品质量必须足够大,以考虑粒度大小的影响,将基本误差、分组误差和离析误差降低到可接受的水平;2)需要采取足够数量的增量样品,以将长期质量波动误差降低到可接受的水平;3)应正确地选择取样位置,以避免由于诸如斗轮取料机和离心泵等设备存在的质量周期性变化所造成的影响;4)附加错误诸如样品污染、样品溢出、颗粒降解和操作员失误等,需要从一开始就加以消除。因此为了消除不良的取样做法,确保取样能够兑现应有的承诺,需要通过改进工作人员的培训和提高认识来确保所取样品没有重大偏差,确保样品的总体精度满足所需的任务要求。
Sampling of iron ore shipments for commercial transactions should be carried out in accordance with ISO 3082.While compliance has improved in recent years,there are still a number of areas where significant issues occur,including:1)Sample cutter design and operation for high capacity streams;2)Division of primary increments at the secondary sampling stage;3)Performance of crushers reducing particle size prior to division;4)Sample mass retained at each sampling stage;5)Sample division.Sampling is where the measurement process begins,so the whole process is corrupted at the outset if the sample is not representative.The“golden rule”for correct sampling is that“all parts of the material being sampled must have an equal probability of being collected and becoming part of the final sample for analysis”.If this rule is not respected,then bias is easily introduced.For example,in practice it is impossible to take a representative sample in-situ from a stockpile or ship.Samples must be taken while the stockpile is being built up or broken down,or while the ship is being loaded or unloaded.After satisfying the“golden rule of correct sampling”,the following requirements also apply for sample station design:1)The sample mass collected must be large enough taking into account the particle size to reduce the fundamental,grouping and segregation errors to acceptable levels;2)A sufficient number of increments needs to be taken to reduce the long-range quality fluctuation error to an acceptable level;3)The sampling location should be selected to avoid the presence of periodic variations in quality due to equipment such as bucket wheel reclaimers and centrifugal pumps.Accessory errors,such as sample contamination,sample spillage,particle degradation and operator mistakes need to be eliminated at the outset.Poor sampling practices therefore need to be eliminated by ensuring that sampling is given the commitment it deserves,by improving staff training and awareness,by ensuring samples are free or significant bias,and by
作者
HOLMES Ralph J.
HOLMES Ralph J.(CSIRO Mineral Resources,Clayton South,Vic.3169,Australia)
出处
《中国无机分析化学》
CAS
2020年第3期1-8,共8页
Chinese Journal of Inorganic Analytical Chemistry
关键词
铁矿
取样
装运
最佳实践
iron ore
sampling
shipments
best practice.
