HBI fines

The Association has previously published articles and circulars on the subject of Direct Reduced Iron (DRI).The precautions necessary for the carriage of DRI are extensive and could, for a standard design of bulk carrier, be considered onerous, given the need for nitrogen blankets and the placing of thermocouples at several levels within the cargo. A somewhat similar cargo called Hot Briquetted Iron (HBI) is considered much safer and the precautions when carrying this cargo are considerably less demanding. The differing requirements for carrying each are detailed in the IMO Code of Safe Practice for Solid Bulk Cargoes. Charterers and shippers are obviously aware that the precautions relating to DRI will result in much additional time and expense and therefore there is, perhaps, a certain reluctance on the part of shipowners to enter into charters, thus reducing the available pool of tonnage. The carriage of HBI does not pose the same problems. Given these differences, discussions on whether a cargo of HBI fines should be treated as HBI or as DRI clearly has a great significance for the safe carriage of the cargo, as well as time and cost implications for the parties concerned.

DRI is manufactured by de-oxidising iron ore. It is the re-oxidisation reaction which gives rise to change in its properties that can lead to problems with carriage. DRI is usually in the form of porous pellets with a relatively high surface area and is therefore prone to rapid re-oxidisation. This re-oxidisation is accelerated when there is a high moisture content.The result is a cargo which gives off (explosive) hydrogen and at the same time is prone to rapid self-heating.HBI, by contrast, is compressed or molded (briquetted) into a form which does not produce a high surface area and therefore does not tend towards rapid re-oxidisation; it is, therefore, relatively safe. During the production, transportation and storage of HBI, large quantities of small particles or dust are produced; these are known as fines. Having a high metal content, this dust or fines is of relatively high value and is collected and stored in the open until sufficient quantity is accumulated to justify sale and the chartering of a vessel. The important point is that the dust or fines, whilst associated with the molding or briquetting production, are obviously not briquettes and actually have many of the same properties as DRI. HBI fines, therefore, can be as dangerous as DRI and perhaps should actually be called DRI. The dangerous nature of the cargo was recently illustrated by an incident involving a Member of the Association.

The ship in question was carrying a cargo of HBI fines from the Caribbean to the Far East via Panama and suffered an explosion in one of the holds whilst transiting the Pacific. Five seamen were seriously injured. The source of the explosion was hydrogen produced within the cargo. Following an evaluation of the cargo by experts it was determined that without a significant flow of air through the holds, hydrogen concentrations could reach dangerous levels within a matter of one or two hours. Being a standard design bulk carrier the ship was not equipped with the forced ventilation system necessary to disperse hydrogen being created at such a rapid rate. Neither was it equipped with the inert gases which would normally be required for the carriage of DRI. This put the Member in a very difficult position when considering how to continue the voyage safely.

The confusing reference to HBI in the term 'HBI fines' possibly misleads the Master and Owners into the belief that the cargo can be treated as HBI, and is further complicated by the fact that companies associated with the shippers or charterers have been known to certify that the cargo is 'passivated' or 'safe'. That certification includes little, if any, useful scientific data on the nature of the cargo which raises a question as to the value and status of any such certificate. The misleading reference to HBI within the term of 'HBI fines' is perhaps just one example of unscrupulous charterers' and shippers' efforts to hide the real nature of the cargo. Masters and Owners should be sceptical of any unfamiliar cargo descriptions especially those descriptions which appear to mix terminologies.

It is very important that where Masters or Owners are in doubt they ask for specific details of the chemical composition, moisture content and size of the particles and, if not satisfied, refer the matter to the Association or relevant experts.