MER GROUP: Nnyinasosɛm a Ɛfa Pelletization Ho Nnianim Tiawa
Wɔ nnɛyi dade adwumayɛbea ahorow a wɔaka abom mu no, pellet ore yɛ adesoa titiriw a ɛkorɔn-su ma dade a wɔyɛ wɔ fononoo a ɛyɛ hyew mu. Pelletization nhyehyɛe no yɛ dade a wɔde ayɛ powder a ɛyɛ fɛ no ho adwuma ma ɛyɛ kurukuruwa a ɛyɛ den-ahoɔden kɛse, ɛkorɔn-grade, na edi ɔhaw a ɛne sɛ wontumi mfa powder pa nhyɛ fononoo no mu tẽẽ no ho dwuma. Wɔakyekyɛ n’adwuma nnyinasosɛm mu titiriw ayɛ no nneɛma atitiriw anan: balling, drying ne preheating, high-temperature roasting, ne cooling ma ɛyɛ nneɛma a wɔawie, na ɛyɛ honam fam ne nnuru mu nsakrae a edi mũ.
I. Balling Stage: Bɔɔl a Ɛyɛ ahabammono a Wɔhyehyɛ
The balling stage marks the beginning of the pelletization process. The core involves mixing fine iron concentrate powder (with particle size < 0.074mm accounting for >80%), binders (te sɛ bentonite) ne nsuo a ɛwɔ disc anaa drum pelletizer mu, baabi a ɛnam mfiri a ɛbɔ ne capillary tumi so na ɛyɛ kurukuruwa a ɛyɛ ahabammono. Honam fam no, wɔ tumi a ɛkyinkyini ne centrifugal adeyɛ ase no, concentrate particles no bata na enyin layer by layer a fine core no yɛ mfinimfini, na ɛyɛ green balls a ne kɛse yɛ 8–16mm. Wɔ nnuru mu no, nneɛma a wɔde kyekyere nneɛma ne nsu yɛ nsu a ɛda nneɛma nketenkete ntam, na ɛma bɔɔl a ɛyɛ ahabammono ahoɔden a edi kan no yɛ kɛse na ama wɔadi ahwehwɛde ahorow a ɛwɔ akwantu ne ɔhyew a wɔde yɛ adwuma akyiri yi mu no ho dwuma.
II. Drying ne Preheating Stage: Nsu a Ɛma Ɛho Hia ne Nea Ɛma Ɛyɛ Den
Kuw a ɛyɛ ahabammono hyɛn grate no mu, faako a woyi nsu a enni mu wɔ ɔfã a ɛyow no mu wɔ digrii 200–400 mu na amma anpae wɔ ɔhyew a ɛkɔ soro mu, na afei wowie nea edi kan a wɔde hyɛ mu den wɔ ɔfã a wɔde di kan yɛ hyew no mu wɔ digrii 900–1000 . Wɔ saa bere yi mu no, magnetite (Fe3O4) a ɛwɔ bɔɔl a ɛyɛ ahabammono mu no yɛ oxidized ma ɛbɛyɛ hematite (Fe2O3), na binder no fa sintering reactions mu ma ɛyɛ ahwehwɛ nkitahodi a edi kan, na ɛma bɔɔl a ɛyɛ ahabammono ahoɔden tu mpɔn kɛse na ɛto fapem ma akyiri yi a wɔayam.
III. High-Temperature Roasting Stage: Crystal a Wɔsan Yɛ ne Ahoɔden a Wɔma Wɔyɛ
Kurukuruwa a ɛyɛ ahabammono a wɔadi kan ayɛ no hyew no hyɛn fononoo a ɛkyinkyini anaa fononoo a wɔde grate no mu ma wɔhyew wɔ 1200–1300℃, a ɛno ne ade titiriw a ɛma wɔyɛ pellet ore su ahorow. Hematite asinasin no san yɛ ahwehwɛ na enyin, na ɛyɛ ahwehwɛ a ɛyɛ den; efĩ te sɛ SiO2 ne CaO a ɛwɔ concentrate no mu no yɛ nsu fã ketewaa bi, a ɛhyɛ nneɛma nketenkete no mu nsonsonoe ma na ɛyɛ nnompe a ɛyɛ den a ɛyɛ den bere a ayɛ nwini awie no, na ɛhwɛ hu sɛ awɔw ahoɔden ne ɔhyew a ɛwɔ pellet ore no mu no gyina pintinn. Saa bere yi nyinaa, ɛhwɛ hu sɛ dade oxides no bɛyɛ oxidation koraa, na ɛma pellet ore no grade ne reducibility tu mpɔn.
IV. Cooling Stage: Adwumayɛ a Wɔma Ɛyɛ Den
Pellet ore a wɔayam a ɛwɔ ɔhyew a ɛkorɔn-mu (bɛyɛ 1000–1100℃) no hyɛn annular cooler no mu, baabi a wɔbɔ mframa a ɛyɛ nwini ma ɛyɛ nwini kodu 100–150℃. Onwini a ɛba ntɛmntɛm no siw ahwehwɛ a ɛyɛ mmerɛw no ano, na ɛma pellet ore no nhyehyɛe ne ahoɔden a ɛyɛ den no kɔ so tra hɔ na ɛkwati sɛ ɛbɛsɛe nnwinnade a edi hɔ no. Wobetumi asan de mframa a wɔsɛe no a ɛyɛ hyew kɛse-a ɛyɛ digrii 300–400 a ɛba bere a wɔreyɛ onwini no akɔ grate no mu de ayow na wɔadi kan ayɛ hyew bɔɔl a ɛyɛ ahabammono, na ama wɔahu ahoɔden a ɛkyinkyini na ɛtew ahoɔden a wɔde di dwuma no so.
Ɛdenam ɔhyew, wim tebea ne bere a wɔhwɛ so pɛpɛɛpɛ wɔ ɔfa biara mu so no, pelletization nhyehyɛe no dan dade pa a wɔde ahyɛ mu a ɛba fam-grade ma ɛbɛyɛ pellet ore a ɛyɛ papa-. Esiane sɛ nneɛma nketenkete no kɛse yɛ pɛ na wotumi tew so yiye nti, ebetumi ama fononoo a wɔde yɛ nneɛma a ɛyɛ hyew ne dade a wɔabɔ no atu mpɔn, na ama ayɛ nkitahodi titiriw wɔ nnɛyi dade ne dade adwumayɛ mu.
