氧化铁皮是钢铁制造过程中的副产品。它是在钢铁制造过程中为热卷钢提供保护涂层的，非常类似于液化前的铁矿粉的一种物质。氧化铁皮的物理性质与初级开采的铁矿粉相似。
氧化铁皮对承运人来说不是一种常见的货物。当氧化铁的上层货物还相当干燥时，下层货物却可能积水。这是一种颗粒状的具有显著的水分含量的货物。
国际海事固体散装货物规则(IMSBC)提醒注意那些运输时含有内在水分含量的粉状矿物货物,无论其是否被列为规则中的A类货物,它们具有潜在的液化风险。
然而,氧化铁皮并未列入国际海事固体散装货物规则中。
《国际海运固体散装货物规则》第1.3节规定未列明的货物，如氧化铁皮、在接受装载以前需要求提供由装货港的国家主管当局出具的证明货物适于海上运输的证书。
国际海事组织2010年10月12日的通讯DSC.1/Circ.63中也指出铁矿粉是一种可能液化的货物,因此属于A组货物,在装运前需发货人向船长提供水分含量以及适于运输的水分限额证书。
氧化铁皮的这种性质使得装运前的水分检测货物取样变得非常重要，不能只关注货物堆的表面部分，应该提取能充分体现货物性质的样品。因为单靠人工挖掘不可能采取到货物堆内部的样品，因此对货物堆进行采样需要利用挖掘机。
托运人应该注意到从货物堆的底部进行排水可以在合理的时间内显着降低货物总体的水分含量。因此，水分含量的降低有可能是决定货物是否能被接受装运的因素。同样重要的是，要保证货物堆遮蔽完好，避免货物被雨水淋湿。
底层潮湿的货物如氧化铁皮,很容易在底货液化后出现货物的移动。上层高密度的货层开始围绕潮湿的底层货物自由移动。并且,由于这类货物的高密度,规则中规定的处理要求为在航程中应保持平整,重量均匀分布于舱底。
Mill Scale Mill Scale Fines
Mill Scale is the by product of the steel making process. It is formed during the steel making process as a means of providing a protective coating on hot rolled steel and it is a commodity much likened to iron ore fines which is liable to liquefaction. The physical nature of Mill Scale is similar to primary mined iron fines and it is traded effectively in the same manner as primary mined iron ore fines.
Mill Scale is not a common commodity to carriers. The upper sections of Mill Scale can appear quite dry whilst water accumulates at the bottom of the stockpile, effectively it is a cargo with fine particle sizes but with a significant inherent moisture content.
The International Maritime Solid Bulk Cargoes (“IMSBC”) Code warns the potential liquefaction hazard of all fine-grained mineral cargoes shipped with inherent moisture content, regardless of whether or not the cargo is specifically identified as a Group A cargo in the Code.
However, Mill Scale is not listed in the IMSBC Code.
Section 1.3 of the IMSBC Code specifies that unlisted cargoes, such as Mill Scale, should only be accepted for loading provided it is accompanied by a certificate issued by the national competent authority, stating the commodities suitability for seagoing carriage, of the country of the port of loading.
IMO Circular DSC.1/Circ.63 of 12 October 2010 also states that iron ore fines are a cargo that may liquefy and therefore a Group A cargo which require shippers to provide the Master with a certificate of the moisture content and the transportable moisture limit (TML) prior to loading.
The wet base nature of Mill Scale that moisture sampling prior to loading is very important, not only is the surface area of any stockpiles but also a fully representative sample taken. As manually digging into the piles is impossible, hence mechanical excavators will be necessary for sample stockpiles.
Shipper should note that it is possible to achieve a signification reduction in the overall moisture contest in a reasonable timescale by draining any water away from the base of the stockpile. Therefore, to accept the cargo for loading or not is very depends on the reduction of the moisture content.
It is also important to ensure adequate covers are placed over the stockpiles to prevent rain reaching the cargo.
Wet base cargo like Mill Scale are prone to cargo shift as the bottom liquefies and the top of the high-density stow becomes free to slide around over the wet based. Also, due to the high density of this cargo, the trimming requirements as detailed in the Code are that it should be trimmed flat for the voyage to distribute the weight evenly across the tank top.
