Background
China’s chromite resources are poor, and the dependence on imports is as high as 95%. With the incremental mining of chromite resources, the proportion of fine ore reaches 3/4. The low-cost and energy-saving process of producing high-carbon ferrochrome with chromite ore powder has great practical significance.
At present, there are fewer and fewer chromium lump ores suitable for direct furnace use, and the price is also rising accordingly. In the international market, the supply of ferrochrome lump ore is small and the price is high, while the supply of chromium ore powder is sufficient and the price is cheaper than lump ore; directly smelting chromium ore powder into the furnace will make the air permeability of the submerged arc furnace will become poor, and the furnace condition will fluctuate greatly, resulting in an increase in the unit consumption of raw materials and power consumption, and in severe cases, it will cause safety production accidents.
A New Production Method of High Carbon Ferro Chrome
The invention provides a preparation method for high carbon ferro chrome, which is simple in operation and has the characteristics of good sintering effect, high sintering efficiency, high ball forming rate, and low energy consumption.
In order to achieve the above object, the preparation method of a kind of high-carbon ferrochrome specifically comprises the following steps:
1. Material selection: select ferrochrome powder as raw material.
2. Ingredients: Put the ferrochromium powder, binder, slagging agent, reducing agent, and regulator into the mixing equipment and mix them, add water to adjust the humidity, and then cold press to form pellets;
3. Sintering: Spread the pellets evenly on the sintering equipment, and set the temperature for high-temperature sintering.
4. Screening: The sintered materials are collected from the sintering equipment into the material distribution sieve; the ore powder that does not pass the material distribution sieve is the sintered product, and the ore powder that passes the material distribution sieve is mixed into the raw material for the second time as the return material. The product is obtained after powder sieving.
The ferrochrome powder and binder, slagging agent, reducing agent and regulator are in proportion (10-16): (0.2-0.8): (0.3-1): (0.15 -1.8): (0.2-1.4).
In step (1), the chromium content in the ferrochromium powder is more than 65%, and the particle size of the powder is 2-25mm.
In step (3), the sintering temperature is 1500-2500°C, and the time is 2-7h.
The binder is cement, the adjusting agent is magnesium oxide, the reducing agent is coke, the coke contains more than 90% of fixed carbon, less than 0.5% of the sulfur element, and the particle size is 2-15mm.
The slagging agent is silica, the content of silicon oxide in the silica is more than 95%, and the particle size is 10-25mm.
The Advantages of the New Production Method of HC Ferro Chrome
Compared with the existing technology, the preparation method of high-carbon ferrochromium introduced in this paper is simple to operate, and the binder, slagging agent, reducing agent and regulator are added, so that the strength of cold-pressed pellets can meet the normal temperature strength and high temperature strength , the room temperature strength needs to satisfy its
It hardens in a short period of time and can meet the requirements of transportation, ensuring that the pellets are not broken or slightly broken during the process from the stockyard to the submerged arc furnace; and ensure the high temperature strength, so that the cold-pressed pellets can enter the submerged arc furnace. Being able to maintain integrity is beneficial to the gas permeability of the charge; it also reduces the power consumption per unit product smelting of high-carbon ferrochrome, improves production efficiency, and reduces costs.
High Carbon Ferro Chrome Production
Select ferrochrome powder as the raw material, and through experiments and tests, the chromium content in the selected ferrochrome powder is more than 65%,
In order to ensure the processing into good high-carbon ferrochrome, and process the ferrochrome powder into a powder with a particle size of 2-25mm through crushing equipment, crushing equipment or grinding equipment, and preferably process it into a 3mm powder.
Ferrochrome powder, bonding agent, slagging agent, reducing agent and adjusting agent are preferably used. The bonding agent is cement, the adjusting agent is magnesium oxide, and the reducing agent is coke. In addition, the carbon in the high-carbon ferrochrome is fully guaranteed. Fusion, the fixed carbon content in coke is more than 90%
Above, the sulfur element content is less than 0.5%, and the particle size is 2-15mm; the sulfur element content is less than 0.5%, so that the pollutants produced at high temperature are small, and for good mixed redox, the slagging agent is silica , the silicon oxide content in silica is more than 95%, and the particle size is 10-25mm.
Ferrochromium powder and binder, slagging agent, reducing agent and regulator are in proportion (10-16): (0 .2-0 .8): (0 .3-1): (0 .15-1 .8): (0.2-1.4), preferably, ferrochrome powder and binder, slagging agent, reducing agent and regulator are in the ratio of 12:0.4:0.5:1.2 : 0.8, reasonably mix ferrochromium powder with binder, slagging agent, reducing agent and regulator, and avoid adding materials again when carrying out the next process
Add the mixed material into water, the water content can be 5%-10% of the total amount, the preferred water content is 8%, so that the mixed material and water can be better combined, and sent to the high-pressure briquetting machine for cold pressing to produce raw Pellets are not only convenient for burning
Knot, and achieve its block.
Spread the completed pellets evenly on the sintering equipment, set the temperature for high-temperature sintering, the sintering temperature is 1500-2500°C, and the time is 2-7h, preferably, the sintering temperature is 1600°C, the time is 3.5h, and finally the sintered
The material is collected from the sintering equipment into the material sieve.
The ore powder that does not pass through the sieve is the sintered product, and the ore powder that passes the sieve
As a return material, it is mixed into the raw material for the second time, and the product is obtained after powder sieving.