Granulated Ferrochromium Size Control via Segmented Distributor
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Solution Overview
Problem
Existing methods for producing granulated ferrochromium, such as the Granshot process and water-blast methods, face limitations in adjusting mean grain size and size distribution, leading to long dissolution times and inefficient alloying in steel and iron melts.
Innovation Solution
A method involving a rotating distributor with specific design features, such as an upper inlet opening, sidewalls, and openings at the lower end, is used to produce granulated ferrochromium with a controlled size distribution, reducing fines and optimizing melting temperature, allowing for rapid dissolution and improved alloying performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional water granulation methods are used, then granules are produced quickly, but the size distribution is wide with high fines content (≤8 mm) up to 20%
Solution Approach 1:
The distributor is divided into multiple segments with different opening sizes (first openings of 10-20 mm and second openings of 2-5 mm) arranged in different radial zones. This segmentation allows different parts of the distributor to produce granules of different size ranges, achieving a controlled size distribution while maintaining high productivity through simultaneous multi-size production.
2Ease of operation
If coarse granules (20-100 mm) are produced, then handling is easier, but dissolution time in steel melt increases significantly
Solution Approach 1:
The invention optimizes the granule size parameters to a specific range (mean size 12-50 mm with controlled distribution) that balances handling ease and dissolution speed. By adjusting the distributor opening sizes and arrangement, the process produces granules that are not too coarse for easy handling but not too fine to cause excessive dissolution time, achieving an optimal parameter combination.
3Temperature
If the ferrochromium composition is adjusted to eutectic, then melting temperature is reduced to 1400-1450°C, but composition control becomes more critical
Solution Approach 1:
The invention adjusts the chemical composition parameters of the ferrochromium alloy to achieve a eutectic or near-eutectic composition, which lowers the melting temperature to 1400-1450°C. This parameter change enables faster melting and dissolution in the steel melt, improving alloying efficiency while requiring precise compositional control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method results in granulated ferrochromium with a mean size of 12-50 mm and ≤7% fines, enabling rapid melting and homogenization, reducing processing time, and improving chemical homogeneity in steel melts, thereby achieving time and energy savings in Electric Arc Furnace operations.
Implementation Method 1
The molten metal is directed from a tundish to a refractory target. The metal strikes the target, splits up and is radially distributed over the cooling water in the tank. The droplets solidify in the tank
Implementation Method 2
Metal granulation in water is a well-established method for rapid solidification of liquid metal into a medium sized product form
Data Source
Figure 1
AI summary
The invention relates to a method of producing ferrochromium by the granulation of a melt comprising the steps of providing a ferrochromium melt comprising (wt. %): C: 1 – 9; 5 Cr: 25 – 70 and Si: ≤ 2.0. The method includes the steps of feeding the melt to a distribution unit, subjecting the melt to granulation by disintegrating the melt above and/or within cooling water held in a cooling tank, solidifying the disintegrated melt within the cooling water, thereby obtaining a granulated ferrochromium material with a mean size in the range of 12-50 mm wherein the amount of fines having a size of less 10 than 4 mm is limited to 7 %.