Main technical parameters and energy consumption description of the
equipment
1. Equipment scheme:
·Loading and feeding methods: automatic feeding, centralized
feeding;
·Smelting operation mode: continuous smelting, timed discharge.
·Electric arc working system: arc melting.
·Discharge method: self-propelled trolley type;
·Casting method: titanium slag tank/cast iron machine;
·Dust removal method: Semi closed low hood, low-pressure pulse bag
dust removal method.
1, The process characteristics of titanium slag smelting:
Titanium slag is a high melting point smelting product. The molten
titanium slag has strong corrosiveness, high conductivity, and the
characteristic of its viscosity increasing dramatically near the
melting point temperature. Moreover, these properties undergo
drastic changes with the composition during the smelting process.
The overall structure of the titanium slag smelting furnace adopts
a semi sealed (upgradable to fully sealed structure) scheme. It is
a special furnace type between electric arc furnace and submerged
arc furnace. When designing a titanium slag electric furnace, the
characteristics of the process of melting titanium slag should be
considered first:
1. The power per unit area of the polar circle is larger than that
of the ore blast furnace, with concentrated heat, which can meet
the requirements for melting high titanium slag;
2. The unit area power of the furnace should be selected to be
smaller in order to form a stable protective layer of titanium slag
around the molten pool;
3. There is a gas chamber area of appropriate height above the
furnace to prevent the molten liquid from completely escaping from
the furnace during slag boiling;
4. The electrode lifting speed should be fast to meet the
requirement of quickly lifting and lowering the electrode when
titanium slag boils.
5. The soft melting crust of the furnace material prevents the
material from automatically decreasing with the generation of slag
and iron, often requiring manual tamping to continue feeding. The
treatment of collapsed material and slag spraying is relatively
difficult.
From the perspective of arc working system, titanium slag electric
furnace is between steelmaking electric furnace and ferroalloy and
calcium carbide submerged arc electric furnace, and is closer to
the former, but also similar to the latter in terms of ore
reduction
2, Process flow of titanium slag smelting
The selection of the process flow for melting titanium slag is
determined by factors such as raw material conditions and taste,
equipment condition, technical level, product use, and economic
factors.
1. Titanium concentrate and anthracite are manually and reasonably
proportioned before being sent to an electric furnace for smelting.
After the smelting is completed, qualified titanium slag and molten
iron are discharged from the electric furnace, and the titanium
slag and molten iron are injected into the slag tank and molten
iron ladle respectively.
3. Titanium slag is processed through water cooling or natural
cooling, crushing, magnetic separation, and ball milling to become
qualified titanium slag products, which are then sent to the
finished titanium slag storage bin.
4. The molten iron is desulfurized to produce pig iron for sale.
5. The flue gas from the electric furnace is treated by a dust
collector and discharged to meet the national emission standards.
3, The workflow of titanium slag smelting furnace
1. Feeding:
Feeding method: One time feeding is compatible with continuous
feeding, and a ramming machine is set up.
Number of feeding ports: seven. Among them, there is one central
feeding port, and the feeding amount accounts for 50% of the
mixture.
Feeding process: Adopting the arc melting method of one-time
feeding (or continuous feeding in the later stage). The titanium
concentrate and reducing agent, which have been pre oxidized and
roasted, are mixed evenly with the furnace material through an
electronic scale. The raw material is transported by a conveyor
from the raw material warehouse to the two large material
warehouses at the rear of the electric furnace melting workshop,
and then transported by a bucket belt conveyor to the top material
warehouse of the electric furnace for storage. After the slag and
iron melted in the previous cycle are released, they are
transported by a belt conveyor to seven discharge pipes and added
to the furnace.
2. Smelting:
The automatic control electrode lifting device is more likely to
play its characteristics in titanium slag smelting furnaces.
3. Out of the furnace:
Use an eye opening machine to open and mix out slag and iron.
4, The equipment features of our company's titanium slag smelting
furnace are:
The electrode lifting system adopts full hydraulic control (or
variable frequency water-cooled motor type) and uses world leading
Parker proportional valve technology to meet all the requirements
for electrode lifting, fully meeting the requirements for rapid
lifting and lowering of electrodes when titanium slag boils.
The automatic control system for electrode lifting is advanced,
with complete control software functions that can adjust the arc
current size and reasonable electrode lifting speed in a timely
manner according to the actual working conditions of the titanium
slag furnace. Fully meet the different smelting characteristics of
the initial, middle, and later stages of titanium slag smelting
process, and achieve independent or linked automatic/manual control
of electrode lifting operation for three-phase electrodes.
3. Advanced distributed control system, the entire titanium slag
furnace is controlled by PLC and equipped with human-machine
interface monitoring display,.
Furnace type selection: Adopting the intermittent melting process
of semi closed low hood electric furnace powder or lump material
feeding into the furnace, it can carry out operations such as
ramming, auxiliary feeding, and adjusting the material surface,
while also recovering waste heat and treating flue gas.
Therefore, the low hood semi closed electric furnace is more
suitable for the smelting of high-grade titanium slag.
4. Hybrid sealed water-cooled furnace cover: composed of a fully
water-cooled metal frame and a plate trapezoidal water-cooled
furnace cover, with refractory material lining inside, it can
achieve the transformation from a semi closed furnace cover to a
fully closed smelting. The sealed structure of the mineral thermal
electric furnace is used for purifying and recovering coal gas. The
electrode holes and feeding holes on the furnace cover are filled
with materials and sealed with water cooling devices.
5. Setting of the ramming machine: The process of melting titanium
slag is an intermittent operation, and the operation of each
furnace mainly includes steps such as feeding, electrode placement,
smelting, and discharging;
According to the characteristics of titanium slag smelting, it is
necessary to use a ramming machine for material accumulation and
crust formation in the furnace.
6. Energy saving short network: composed of water-cooled
compensator, water-cooled copper tube and water-cooled cable,
adopting a new energy-saving short network structure with double
wiring and outer triangle layout. The natural power factor is high.
7. Graphite electrode selection: The electrode allows for a high
current density to pass through, ensuring a reasonable power supply
system, which is beneficial for shortening melting time and
reducing power consumption.
8. Electrode copper tile: Each phase electrode is tightly held with
four copper tiles, which work reliably, are not prone to arcing,
and have a long service life.
9. Implement automatic electrode pressing and pulling: The
electrode holding brake adopts double hydraulic disc spring holding
brake technology from a large ferroalloy smelting furnace. When the
electrode is clamped, the disc spring automatically presses and
holds the electrode, which has a long service life, simple
operation, and reliable performance far superior to single holding
brake devices. The pressure ring is used for clamping, and the
conductive plate is clamped and released by a hydraulic cylinder.
The upper and lower brake and pressure release cylinder can be used
for manual and automatic fixed length pressure release.
10. Electric furnace transformer: It adopts a low loss
energy-saving transformer with side outgoing lines, which can be
overloaded by 30%. It has on load electric voltage regulation,
strong oil-water cooling, and is equipped with complete oil
temperature and gas protection devices.
11. High voltage electrical appliances: The control adopts a vacuum
switch cabinet, which has complete detection, measurement, and
relay protection for voltage, current, power, and electricity. Zinc
oxide lightning arresters are installed to absorb operating
overvoltage.
