Undersized iron ore pellets, or broken iron pellets which are rejected products of iron ore pellet production, have significantly less price than usual iron ore pellets. Why?
If it is not usable, why the customer buy this product?
If it is usable, why the price is just 50% of the main product value with the same chemical specifications?
#Iron_ore #price #ironore #pellet
Their number is very small compared to the total and can be ignored.
So it does not change the price so much.
Yes they can be used.. from size range of 4 mm to 8 mm ... For that re-screening of the same pellets is required prior to charging into blast furnace. To utilise in more economical way, the blast furnace shall have facilities of bell less charging with movable feed chute. And advance system to monitor gas dymaincs, permeability monitoring in charging rings. .. through this setup, we can charge the mini pellets/broken pellets (4-8 mm) in the desired rings for better permeability and productivity.
It may depend upon the composition of process gas composition when you determine the workable quality of the input pellets. If %H2 is higher than %CO, you need high grade DRI pellets because bustle gas temperature is higher. Thus, uncooked and undersized pellets may not be a good option. Secondly, in order to maintain the bed permeability as per Ergun Bed equation, undersize pellet are not favorable. Problems encountered may be accretion of DRI which leads to formation of pockets and uneven gas distribution.
Yes these can be a part of total fed to both blast furnace, Midrex and any smelt reduction processes like COREX, Finex. Any Raw material less than 6mm are considered as fines for bigger size blast furnaces. So small Size less than 6 mm will be treated as fines and are avoided in BF. If the total Pellet % in burden is less than 15% then Under size pellets with good physical properties (TI, CCS) can be charged to BFs (as a mixed with 10 to 12 mm Pellets).
I think broken Pellets are not to be charged to BFs, however it can be a good fed for Midrex, COREX and Finex with a controlled manner.
So far as cost is concern a fed material will both physical and chemical suitability for usage. Though the broken pellets have chemical properties intact but with very inferior physical properties. Small size are considered to have process deviations so very limited customers may leading to lower cost.
Giving a different look for this question, maybe if the classification process before the pellets heating was increased, it can provent the formation of too many undersized iron pellets. There are some well known technologies that can be very efficient in monitoring the particles format, like high definition cameras, that combine with actuators can be applied to prevent the undersized iron pellets to continue into the process. By reducing drastically the amount of these problematic pellets, maybe it can address a different solution to solve the same problem.
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