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Electromagnetic pure iron is a type of high quality steel containing over 99.5% of iron with quite low
content of remained elements and featuring with soft texture, strong toughness, easy process and
high electromagnetic performance. Based on its magnetic property, the electromagnetic pure iron
can be classified into three grades: DT4A, DT4E and DT4C. Based on various applications, the
electromagnetic pure iron can be classified into iron core purpose, soft magnetic purpose,
electronic lock purpose, space instruments and military purpose, electron tube purpose and
easy turning electrical purpose.

Electromagnetic pure iron was applied to not only the cutting-edge engineering of national defense
work, but also industrial fields such as relays, instruments and direct current motors. wire and rod
products were mainly used to the civil industry, take the absolute advantage at middle and high-end
and keep growing stably. In recent years, depending on the customer’s requirements, newly
developed ultra-low coercive force electromagnetic pure iron featuring more stable magnetism,
better processing property and lower cost which has been widely used to work and life necessities
in the fields of medical imaging, superconducting power generation and strong/weak magnetic field
shielding of the communication devices.

High-purity iron with purity of 99.987 wt.% was prepared employing a process of direct reduction–melting
separation–slag refining. The iron ore after pelletizing and roasting was reduced by hydrogen to obtain
direct reduced iron (DRI). Carbon and sulfur were removed in this step and other impurities such as
silicon, manganese, titanium and aluminum were excluded from metallic iron. Dephosphorization was
implemented simultaneously during the melting separation step by making use of the ferrous oxide (FeO)
contained in DRI. The problem of deoxidization for pure iron was solved, and the oxygen content of pure
iron was reduced to 10 ppm by refining with a high basicity slag. Compared with electrolytic iron, the pure
iron prepared by this method has tremendous advantages in cost and scale and has more outstanding
quality than technically pure iron, making it possible to produce high-purity iron in a short-flow, large-scale,
low-cost and environmentally friendly way.

We can produce the special type which you ask Applications High purity iron is used largely as the basic
material for (re-)melting of low-carbon, Stainless and acid-resistant steels, materials with a high nickel content,
magnetic alloys as well as stainless and heat resistant steel castings in induction and vacuum furnaces. High
purity iron is also used in many applications of aviation construction, nuclear Technology, the production of
magnets (pole cores, yokes and armatures), in automotive construction, as magnetic shielding, as welding
rods and fuse wire, as gasket in the chemical and petrochemical industry, power station construction, as
anti-corrosion anode and as galvanizing tank including equipment. Mechanical properties Brinell hardness (hb)
High purity iron Max. Typical Cold-rolled strip / sheet 105 90 Hot-rolled strip / plate 105 90 Quarto plate 100 90
Round bar 110 95 Electrical and magnetic properties Characteristics typical values Initial permeability 300 – 500
Permeability 3500 – 6000 Coercive force 60 – 120 a/m Saturation induction 2.15 t Density at 20 °c 7.86 kg/dm³
Melting point 1536 °c Linear expansion coefficient Temperature range 0 – 100 °c 12×10-6 1/°c Modulus of
elasticity 207 kn/mm²

Pure iron, which refers to iron with very few impurities, has excellent properties such as low coercivity,
high ductility, soft texture as well as good performance in thermal conductivity and electrical conductivity.
High-purity iron is widely used in aerospace, radio engineering, the atomic industry and other fields.
It is an important raw material for the production of precision alloys, superalloys, advanced heat-resistant
alloys, amorphous alloys, soft magnetic materials, permanent magnet alloys and other materials. In recent
years, pure iron has been paid more and more attention due to its extensive use and high added-value.

Pure iron is generally categorized as electrolytic iron and technically pure iron. Electrolytic iron can be
prepared by electrolytic refining of high purity ferrous salt solution obtained by ion exchange or solvent
extraction. The purity of a conventional electrolytic iron is about 99.9 wt.%, containing gaseous impurities
such as carbon, nitrogen, oxygen, hydrogen, sulfur and chlorine of more than 500 mass ppm in total.
To obtain higher-purity products, zone refining, electromagnetic levitation melting and vacuum induction
melting are used to further purify electrolytic iron. Since a single purification method cannot meet the
requirements of preparing ultra-high-purity iron, it is necessary to combine various purification methods.
The common process is ion exchange + solvent extraction → electrolytic refining → cold-crucible
melting → zone refining. Many efforts have been devoted to the preparation of high-purity iron.
succeeded in making ultra-high-purity iron of 99.999 wt.% from pure iron by electron beam zone refining
in an atmosphere of ultra-high vacuum. et al. [3–5] made a 7.5 kg ultra-high-purity iron ingot by
careful refining of high purity electrolytic iron. The purity of the purified iron was determined to be
99.9988 wt.% by chemical analysis of 33 elements. et al. [6] developed a process consisting of anion
exchange in a HCl solution, hydrogen reduction and plasma arc melting for the production of semiconductor
grade high-purity Fe with 99.998 wt.% purity. After improving the refining efficiency, the purity of Fe
achieved 99.9993 wt.%

At present, the pure iron that has been produced and applied industrially is called technically pure iron,
with purity ranging from 99.6% to 99.8%. As a raw material for smelting various special alloys such as
superalloys, heat-resistant alloys, precision alloys and maraging steel, technically pure iron has been
widely used in metallurgical industry. Technically pure iron is produced by pyrometallurgy. Firstly, iron
ore is reduced to pig iron in a blast furnace, then excessive carbon is removed by the basic oxygen
furnace (BOF) or electric arc furnace (EAF), and impurities are further eliminated via a secondary refining
route, through which the required purity level is achieved.

During the past few years, the demands for high-quality materials have grown more and more. Some alloys
(e.g., heat-resistant alloys) use technically pure iron in smelting raw materials, but the impurities such as
oxygen, phosphorus and sulfur in technically pure iron are not invariably low. These impurities cannot be
eliminated readily during the alloy smelting process, leading to the situation that the alloy cannot achieve the
desired performance [8]. The quality improvement of technically pure iron produced by hot metal from a
blast furnace is hindered by impurity elements. Besides removing the impurities such as silicon, manganese 
and phosphorus, oxygen is injected to remove excess carbon in hot metal. Blowing oxygen causes an
excess of oxygen to be brought into the hot metal, after which it is necessary to add aluminum or strictly
control the C–O reaction using a vacuum for further deoxidation. This lengthy and complicated process,
which revolves around decarbonization and deoxidation, violates the original intention of purification and
makes it difficult to produce pure iron with high cleanliness. On the other hand, the concentrations of gas
impurities (C+N+H+O+S) in common commercial electrolytic iron are generally high. Further refining would
increase the cost and make it difficult to achieve an efficient production. The high-purity iron or ultra-high-purity
iron with 99.99–99.999% purity is too expensive ($7000–200,000 US dollars/tonne) to be used on a large scale.
Research and development of high-purity iron is still in the small-scale laboratory stage, and the supply cannot
meet the demand. Therefore, the manufacture of pure iron has great market potential and profit margin.
How to use short-process, low-cost and environmentally friendly manufacturing technology to produce
high-quality pure iron is the future direction of research.

In this study, an approach of producing high-purity iron is proposed via a direct reduction of iron ore–melting
separation–refining process, by which high-purity iron with purity up to 99.987% can be produced on a large
scale with low cost. The process mainly includes three major steps: Step 1, the iron ore after pelletizing and
roasting is reduced by hydrogen, and direct reduced iron (DRI) that is carbon-free is obtained. Some impurities
such as carbon, sulfur, silicon, manganese, titanium and aluminum cannot be reduced or get into iron in this
step. Step 2, the direct reduced iron is separated into gangue (slag) and metal by melting. In this step, the
composition of slag is adjusted to dephosphorize, if necessary. Step 3, the high basicity slag is dosed to
refining for deoxidation. Similar to the process investigated in this study, researchers have studied the process
of smelting pure iron with DRI in an induction furnace, which has delivered good results. However, these results
still have the capacity to improve the impurities removal in pure iron, especially in solving the problem of
deoxidation of pure iron, so the purity has not reached a high grade. As a comparison, the chemical compositions
of pure iron in this work, typical technically pure iron and typical commercial electrolytic iron, are shown in Table 1.
The purity of pure iron produced by the process has exceeded that of commercial electrolytic iron and technically
pure iron. When the purity of pure iron reaches 3N level or above, it is very difficult to further improve the purity,
and the increase of cost and price brought by this is an exponential growth. The pure iron obtained by this method
has tremendous advantages in cost and scale compared with electrolytic iron and has more outstanding quality
than technically pure iron. This is because this process takes full advantage of the purity advantage of DRI and
solves the problem of deoxidization of pure iron in the context of large-scale production. This paper mainly
expounds upon the experimental process and related mechanism of producing high-purity iron by this method,
as well as the feasibility of industrialization.

Table 1. The chemical compositions of pure iron in this work, typical technically pure iron and typical commercial electrolytic iron (wt.%).

Element Pure Iron in This Work Typical Technically Pure Iron Typical Commercial Electrolytic Iron

C   0.0024   0.0030   0.0057

Si   0.0011   0.0100   0.0030

Mn   0.0003   0.0400   0.0003

P   0.0018   0.0021   0.0005

S   0.0005   0.0016   0.0018

Cr   0.0009   0.0100   0.0003

Ni   0.0005   0.0100   0.0032

Al   0.0015   0.0150   0.0011

Ti   0.0003   0.0011   0.0009

Cu   0.0001   0.0100   0.0015

Mo   0.0007   0.0020   0.0004

V   0.0005   0.0020   0.0003

N   0.0015   0.0025   0.0038

H   0.0001   0.0001   0.0013

O   0.0010   0.0030   0.0574

Purity of Fe   99.9868   99.8876   99.9185