HIsmelt Technology Sets New Production Record in China Posted on October 25, Comments Off on HIsmelt Technology Sets New Production Record in China The Shouguang Shandong plant has reached the milestone of days of continuous operation producing, on average, more than 55, tonne hot metal per month HIsmelt is a breakthrough iron making technology that has attained full-scale commercial viability and is taking rapid strides in China where clampdown on traditional BF facilities have been ramped up of late, due mainly to ever-growing environmental concerns, and the thrust is definitely on non-BF iron and steelmaking research. China commissions first commercial HIsmelt plant in Shandong province, which can produce steel using low-grade Iron ore fines and non-coking coal. Remarkable Record While production statistics of the Shouguang Shandong HIsmelt plant in China were floating in the public domain since the plant achieved three months of continuous production in — after the first charge in August — news has recently trickled in that the plant has completed days of continuous operation, thereby setting a new running record, with average hot metal production of more than 55, tonne per month. It will soon resume operations after a few days of maintenance.
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It is a direct smelting process for making liquid iron straight from the iron ore. The process has been developed to treat iron ore fines with minimum pretreatment, making the process more flexible in terms of the quality of iron ore it can treat.
The process allows the use of non coking coal and iron ore fines with significant impurities. The core of the HIsmelt process is the smelt reduction vessel SRV which has a refractory lined hearth and water cooled upper shell.
The process is carried out in this vessel. The refractory hearth contains the molten iron bath and liquid slag. The main product of the process is liquid iron or hot metal which can be used in steel melting shop or cast in pig casting machine to produce pig iron. The byproduct of the process is slag and the off gas. Main features of the process HIsmelt process has the following unique features. The method of solid injections using high speed lances ensure that the capture efficiency in the melt is high and even ultra fines can be used directly.
Coal performance has virtually no dependence on particle morphology, since the coal is ground fine for injection. Trials were conducted in a 60 tons OBM converter to demonstrate the fundamentals of the smelt reduction process. The SSPP operated from to and proved the viability of the technology.
Construction of the HRDF with a design capacity of , tons per annum, commenced in The main objective of the HRDF was to demonstrate the process and engineering scale up of the core plant and to provide operating data for commercial evaluation. The horizontal vessel was operated from October to August Whilst scale-up of the process was successfully demonstrated, the complexity of engineering a horizontal vessel limited its commercial viability.
To overcome this deficiency a design was developed for water cooled vertical vessel. Design and engineering for the vertical SRV Fig 1 was completed in The main improvements incorporated into the design included a stationary vertical vessel, top injection of solids, a simplified hot air blast lance, a fore hearth for continuous tapping of metal and water cooled panels to overcome refractory wear problems.
The vertical vessel demonstrated major improvements in terms of refractory wear, reliability, availability, productivity and simplicity in design. This vessel addressed all the key requirements for a successful direct smelting iron making technology — combining a high level of technical achievements with simple engineering concepts and plant technology.
This stage of operation confirmed that the process was ready to be scaled up to level of a commercial plant. Located in Kwinana, Western Australia, the merchant pig iron facility was designed and engineered with a 6 meter hearth diameter SRV.
Construction of the plant was started in January Cold commissioning commenced in the second half of while the hot commissioning was carried out in second quarter The plant had achieved a production rate of 80 tons of hot metal per hour in early with a coal rate of kg per ton of hot metal.
The plant is presently in the closed down condition. To develop the HIsmelt technology further, Rio Tinto has signed a development agreement with a Chinese steelmaker. The new plant is expected to be commissioned in The partnership seeks to finalize the development of HIsmelt technology and to work together to further improve the technology to higher levels of environmental and economic performance.
Process The basic mechanism of the process is the reduction and smelting of the iron bearing ores with the dissolved carbon in the bath.
The process uses high velocity injection of coal and ore into the melt through downwardly angled water cooled injection lances.
Injected iron ore fines are injected deep into the bath where they are reduced instantly on contact with carbon dissolved in the bath for smelting to take place. This reduction reaction produces iron Fe and carbon monoxide CO.
Reaction gas CO and coal devolatilization products which are generated from deep within the bath form a fountain of mostly slag and some metal. Heat supply to maintain the necessary thermal balance comes by the combustion of reaction gas mostly CO in the upper part of the SRV. This combustion occurs in the relatively oxidizing region in the upper section of the SRV. The heat transfer between the upper oxidizing regions to the lower reducing region is achieved in such a way that the oxygen potential gradient is maintained.
This is done through large amounts of liquid splash moving between the two regions. Liquid slag and metal splash acts as a carrier of the heat. The main product of the process is hot metal. Hot metal is tapped continuously through an open forehearth and is free of slag. Typical temperature of hot metal is around — deg C and typical composition of the hot metal is as follows: Carbon — 4.
HIsarna ironmaking process
In CRA now Rio Tinto recognised the potential of the Klckner steelmaking converter technologies to be adapted to smelt iron ore instead of gasifying coal and melting scrap. CRA formed a joint venture with Klckner Werke to pursue the steelmaking and smelting reduction technologies. Trials were conducted in a 60 tonne OBM converter to demonstrate the fundamentals of the smelt reduction process. With a capacity of , tpa, the design was based on a horizontal, rotating Smelt Reduction Vessel SRV that used bottom tuyeres for injection of coal, oxygen, fluxes and iron ore. The SSPP operated from to and this phase of the project proved the viability of the technology.
High Hopes for HIsmelt Technology in China
Tapping slag at the HIsarna pilot plant The HIsarna process is a smelting reduction process with two directly coupled process stages in which the production of liquid pig iron takes place. The HIsarna plant is shaped like a wine bottle: a "bottle" at the bottom and a thin "neck" at the top. The geometry of this furnace causes a cyclone to form in the neck when the crushed iron ore is injected into this cyclone together with oxygen so oxygen is injected at the top rather than at the bottom. The heat of the cyclone causes the initial partial reduction reaction to take place that reduces iron ore to iron. Here the droplets fall from the wall into the molten slag, which sits on top of the liquid iron bath in the bottom of the furnace. Between the cyclone and the slag layer, oxygen is injected through water cooled lances to generate heat by partly combusting the gasses being released from the final reduction reaction step that takes place in the slag. Powder coal is injected into the slag layer, again through water cooled lances.