Talk:HIsarna ironmaking process

Pig iron pellets

The "pellets" refer to an intermediate product of the steelmaking process used by Tata IJmuiden and other ULCOS partners. Before introducing iron to the blast furnace, they process raw ore into pig-iron/coal pellets. These pellets are very porous, which creates a large reactant surface of pig iron and coal for the hot air in the blast furnace. This has the effect of lowering the amount of energy needed to process a given weight of iron, because it will melt and react more rapidly.

The point of HIsarna is that you don't need the preprocessing step anymore; HIsarna improves the reaction efficiency for powder ore and coal and avoids the downsides of powdered coal from the regular process. -- BenTels (talk) 21:33, 15 July 2012 (UTC)

The Clarification Requested

(Mkhomo (talk))The article as written jumps into one specific variant of Direct reduced iron (DRI) in an idiosyncratic context. There are many DRI processes that have been developed over almost 50 years. The original goal was to produce direct reduced iron (in solid state).

1. The SLRN Process : In 1965 the very first DRI developed was the Outokumpu Process by a consortium including STELCO of Canada, Lurgi, Republic Steel (USA) and National Lead, which caused the process to also be commonly known as SLRN. This process adapted the conventional limestone-to-lime converting kiln into an iron ore and coal fines iron reduction kiln which produced sponge iron which was 'refined' by magnetic separation of iron from gangue (aluminium silicates), ash and unburnt coal. The process had high effluent of pollutants and low throughput, but was seen to be effective with a 95% yield . Further DRI Process Improvements included:
2. Kobe Steel's ITmk3 (Iron Technology Mark III) direct reduction process which improved throughput (but not the other drawbacks) by using a rotary hearth semi-fluidised bed furnace operating at 1500 Celcius. Iron nuggets had to still be magnetically separated from slag with size screening.
3. Kobe Steel's MIDREX shaft furnace process operating at higher temperature using hydrocarbon (natural) gas in place of solid coal and producing hot iron briquettes which were cleaner. Its disadvantage was fuel losses due to incomplete combustion of hydrocarbons.
4. FINEX process by Siemens VAI and RIIST (Research Institute of Iron and Steel Technology) and POSCO of Korea which instead continued using coal fines in a fully fluidised bed reactor and used the effluent hydrocarbon gas to smelt the iron for a fluid iron / slag separation in a second stage. Although high in throughput the high abrasion wear of the reactors became a disadvantage.
5. Originally developed by VOEST-ALPINE , a more commercially successful COREX process now owned by Siemens VAI used a pre-fluxed and coal impregnated iron ore pellet as charge for the vertical shaft reduction reactor. Reaction mass transfer relied on high porosity of the pellet charge. COREX included a second stage smelting and liquid iron / slag separation. A number of COREX plants are commercially operational. Its drawback remains the high level of combustible effluent gas which is usually exported to an electricity generation plant to make the overall process economically viable. (Incidentally, The ~EX for extraction trade names allude to a process feature so they may serve as mnemonics, with MIDREX referring to Methane Iron Extraction, FINEX for Fluidised Iron Extraction and COREX for COAL ORE Extraction respectively).
6. The ROMELT hearth furnace by Moscow Institute of Steel and Alloys which employs two simple principles of an active bath reactor akin to an open hearth steel furnace, except that it is sealed and with injections of oxygen and other ore fines coal and flux charge reactants; and a boiler / steam turbine electric re-generator for export gas energy recovery. ROMELT has been assessed to be versatile with respect to coal and ore charge quality, but since it has no commercial installation, is considered largely experimental but the process has been tested at the large pilot-industrial plant of Novolipetsky Steel Works (NLMK).
7. Similar to ROMELT, but more a mutation of a Blast Furnace and Basic Oxygen Furnace (BOF) vessel is HISMELT developed by a Rio Tinto Group subsidiary (also named HISMELT ). A conventional Blast furnace relies on a vertical shaft down which charge descends while combustibles and hot heat transfer gases ascend, with hot air entering the furnace from tuyeres located at the lower section above the hearth. The migration of melting and reducing charge above is intermediated by a matrix of coke which remains solid and combusts partially into reducing CO which exits at the top as spent reduction product CO2. HISMELT reverses this flow configuration by top-blowing oxygen enriched pre-heated air blast as per BOF and also injecting fluxes, coal and ore fines per BOF/EAF steel making refining lances located below as per blast furnace tuyere locations, into the molten charge in the hearth. The downward top blast is also guided into a vortex flow to further enhance agitation of the gaseous eruptions that rise from the bath. The partially oxidised rising bath effluents get fully oxidised as they encounter the oxygen enriched top blast and the hydrocarbons in off-gas generated exit in a top flue more spent than in other DRI processes, although amenable to further combustion for complete energy recovery. HISMELT is an acronym for High intensity Iron Smelting.
8. Finally according to this present article is the HISARNA process, an apparent hybrid variant of HISMELT, retrofitted from a earlier Tata Steel ULCOS[[7]] DRI process which was most likely of the COREX genre (hence 'pig iron pellet'). Specifically this prior installation was referred to at ULCOS as an experimental blast furnace using a COREX-like iron ore pellet charge.

Rio Tinto distinguishes HISARNA in the DRI evolution of HISMELT as having added the ability to capture and store CO2 directly without separate CO2 scrubbing . But this feature is not DRI per se but a separate vacuum-pressure swing adsorption VPSA gas separation technology for removing CO2, leaving off-gases that may then be reused to reduce CO2 effluents. HISARNA therefore is not actually a DRI technology distinct from HISMELT but rather a supporting unit process. As an example a DRI input unit process enhancement such as the SASOL-LURGI coal gasifier allows the use high ash coals in the DRI chain by pre-gasification and exporting the gas to a MIDREX type reactor. But implementing a such chain does not amount to an improvement of MIDREX. HISARNA is therefore largely a marketing trade name for a specific implementation of a HISMELT DRI process chain.

Given that background, the article confuses the readership with the term Pig Iron Pellet to refer to COREX (process (5) above) iron ore pellet charge used by HISARNA's predecessor plant at Corus, with perhaps a solid sponge iron product of say SLRN (process (1) above), or the powdered iron product of ITmk3 (process (2) above), or the hot briquette iron of MIDREX (process (3) above), or possibly a hot iron briquette produced at the ULCOS experimental blast furnace. This confusion is corroborated in BenTels above posting. I suspect it is the peculiarities of the ULCOS installation and the history that causes the author's terminology to ignore other meanings.

With HISMELT for example, a founding consortium member Nucor sought just the pig iron product, which had to be cooled from the HISMELT process, from liquid hot metal to solid pig iron proper. Pig iron is a historical term referring to the carbon-saturated solidified blast furnace hot metal. In the beginings of HISMELT development, the solidified product (per Nucor) is referred to as pig iron; but it is common in industry for identifying descriptors to cross contextual boundaries, hence the use of the term pig iron pellets when actually referring to COREX premixed charge pellets. Pig iron pellets should actually only best refer to the MIDREX hot iron briquettes although these are not legally a pig but metallic sinter. The pig in pig iron was originally the pig-like lump that medieval foundry workers recovered from their then small iron furnace casts. Pig iron is the carbon saturated metal solidified from a blast furnace cast. Blast furnace lore maintains that it was 'pig' due to the occasional squeal as the solidifying melt blocked further escape of gasses from the solidifying cast. The article can be minimally clarified by altering 'Pig Iron Pellet' to 'Iron Ore Pellet' and by distinguishing the unit processes in the various ULCOS projects and by not giving the impression that HISMELT has been improved upon by UCLOS but rather that the ULCOS proving prototype has migrated from COREX DRI to HISMELT DRI. It may also help if the ULCOS writers are clear as to whether their HISARNA experiment actually includes BOF refinement into steel !within the HISMELT vessel! for if not, they should limit their description to Ironmaking and not Steelmaking.

On looking into this last observation, the article as written also contains historical inaccuracies, especially with the consistent use of the term 'steelmaking' where 'ironmaking' would have served better. The history section gives the impression that the HISARNA DRI concept originated with the Hoogovens Cyclone Converter Furnace. But the article history repeatedly indicates that all the Hoogoven research efforts came to naught. The proper history of 'HIRSANA', which should be better known as HISMELT DRI process lies with the unique Klockner Werke bottom blown basic oxygen steelmaking process used at their now defunct Maxhutte Steel Works of Bavaria Germany and which works lent its name to process (OBM) 'Oxygen Blown Maxhutte' steel or KOBM 'Klockner OBM' steelmaking process for reducing, say, unwanted vanadium from molten steel.

It so happens that Broken Hill Proprietary's New Zealand (BHP NZ) operations at Glenbrook New Zealand found KOBM to be useful at treating their high titanium dioxide iron ores, hence adapted KOBM into their operations. It is possible that this awareness of BHPNZ crossed over to neighbouring Australia where a then Australian division of Rio Tinto's, viz. Rio Tinto Australia (CRA) aggressively pursued this technology by entering into a development joint venture with Klocker Werke to adapt KOBM to smelting iron ore. CRA which later became a group member of Rio Tinto Group persisted in this effort even after Klocker dropped out, and finally succeeded in issuing forth what is now celebrated as HISMELT. The upside of this article's faux pas to me though is the realisation that HISMELT can actually be developed further to combine iron and steelmaking in closely coupled unit processes if not in a merged vessel.

I'm posting this for others to use in responding to the clean-up post as I have no inclination to retrofit the author's writings, given the original intention to post on ULCOS' HISARNA but neither on DRI evolution nor on HISMELT, which the UCLOS author only mentions in passing.(Mkhomo (talk) 11:04, 22 October 2012 (UTC))

In acceptance of my 'talk' contributions I believe the only remaining issue is in the 'Process' article section that indicates that HISARNA is a Steel-making process rather than Iron-making! SARN-Folk, Water is to Ice as Iron is to Steel. Thanks. — Preceding unsigned comment added by Mkhomo (talk • contribs) 10:02, 2 November 2012 (UTC)

HIsarna Ironmaking Process

As already mentioned in a talk contribution below HIsarna is not a steelmaking process, but an ironmaking process. This ironmaking process produces liquid iron with a high carbon content, which can be refined to steel through e.g. the BOF steelmaking process. Is it possible to change the page title? Or otherwise, start a new page called HIsarna Ironmaking and refer to that from this page?

Further to that, the text contains various technical mistakes and misinterpretations. The process does not use iron pellets or DRI