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6. Direct reduction of iron from ironstone


The traditional technology for the blast-furnace-converter steel manufacture has several weaknesses which are fundamental and cannot be diminished in this technology. 

TWINN, LLC has developed and created a pilot plasma-arc system F-200 adapted for theconstruction of the main parts and for direct iron reduction from ironstone technology, solving series of scientific problems, mathematic modeling and optimizing of the process for further transition to the industrial level.

The primary strengths of this technology are:

1. The use of a gaseous reducing agent including methane, natural gas, carbon monoxide, hydrogen, gas synthesis and the pulverulent coal including energetic.

2. An opportunity to process pulverulent ironstone, concentrates, almost any ferrous by-products with a minimal pre-process preparation.

3. The metal product is either cast iron or steel ingot.

4. A Relatively simple utilization of secondary energy resources (the heat of cooling water, the energy of waste gas).

5. Compactness of the plasma-arc system. The specific productivity goes up to 200 tons/m3·day exceeding the blast-furnace productivity by 100 times and any other system for an alternative strategy for direct iron reduction by 10 times.

6. An opportunity to start and stop the system multiple times.

7. The simplicity of the construction and reliability of the plasma-arc system operation. Low capital and operation expenses.


The composition of the system consists of the following parts (fig.6.1):

Fig.6.1.Plasma-arc system.

1. Plasma-arc furnace (1) with a heat-exchanging unit (2);

2. Remote control for the plasma-arc furnace (3);

3. The water cooling system for the plasma-arc furnace including remote control (6), pumps (14), (15), water reservoirs (16), (17) and cooling tower (21);

4. The power-supply system for the plasma-arc furnace including diesel-engine generator (19), storage tank with diesel oil (22), rectifying device (18), contactor (13) and electric service panel (4);

5. The gas-supply system for the plasma-arc furnace including a room with gas cylinders (20) and a remote control (5);

6. The system for furnace vacuum treatment and gaseous reducing agents withdrawal (12);

7. Ironstone and ligature induction system (fig. 2 and 14).


Appearance of the plasma-arc system is shown in fig.6.2; fig. 6.3shows an iron ingot from the direct reduction.

Fig. 6.2 Plasma-arc system.

Fig 6.3 Iron ingot. Reducing gas - hydrogen.