The high zinc content of this waste means that it cannot be
recycled back into the steelmaking process due to the accumulation
of zinc in the Blast Furnace, leading to poor processing
conditions. High zinc containing wastes are known to be stored
across the China and world countries with no economically feasible
method of recovery.
Zn recovery is the economic driver for EAF dust recycling, and the
environmental drivers relate to Fe recycling and the impact of
local stockpiling. Extensive research has been carried out into
potential recovery methods, including the use of Rotary kiln
Furnaces.
Hengyang Industry provides a summary of existing (high technology
readiness level) and potential future (low to medium technology
readiness level) methodologies for Zn recovery from EAF dust. This
includes landfilling/stockpiling, external recovery, Rotary kiln
Furnaces, Sinter Plants, hydrometallurgy, Micro Cavitation Ducts,
and Oxidative Ionothermal Synthesis.
Zinc oxide rotary kiln working principle is the whole process and
principles of the calcined zinc, zinc-containing materials.
Generally it adopts the zinc oxide rotary kiln to process of the
zinc-containing filter cake. The zinc in the filter cake mainly
exists in the form of zinc ferrite, oxide and sulfate. Under the
high temperature in the rotary kiln, the zinc ferrite and solid
carbon will produce the reaction for oxide-reduction, then it will
get the zinc, at the same time lead and cadmium sulfate also be
reduced, will volatilize in the form of sulfide and gold bucked
out. The reduced and volatilized metal from the solid phase will be
re-oxidation, and finally will be produced in the form of oxide.
Technical Parameter
| Model | Kiln size | Motor Power | Total weight |
|---|
| (m) | Diameter(m) | Length(m) | Slope(%) | Capacity(t/d) | Rotating speed(r/min) | (kw) | (t) |
| Φ2.5×40 | 2.5 | 40 | 3.5 | 180 | 0.44-2.44 | 55 | 149.61 |
| Φ2.5×50 | 2.5 | 50 | 3 | 200 | 0.62-1.86 | 55 | 187.37 |
| Φ2.5×54 | 2.5 | 54 | 3.5 | 280 | 0.48-1.45 | 55 | 196.29 |
| Φ2.7×42 | 2.7 | 42 | 3.5 | 320 | 0.10-1.52 | 55 | 198.5 |
| Φ2.8×44 | 2.8 | 44 | 3.5 | 450 | 0.437-2.18 | 55 | 201.58 |
| Φ3.0×45 | 3 | 45 | 3.5 | 500 | 0.5-2.47 | 75 | 201.94 |
| Φ3.0×48 | 3 | 48 | 3.5 | 700 | 0.6-3.48 | 100 | 237 |
| Φ3.0×60 | 3 | 60 | 4 | 800 | 0.3-2 | 100 | 310 |
