7/27/2019 Multiple Hearthing Roasting Furnace Metalurgi

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Multiple Hearthing Roasting Furnace adalah nama sebuah alat ekstrasi metalurgi.

Multiple Hearth Roaster dapat juga digunakan secara luas untuk mengoksidasi, sulfatizing,

chloridizing, volatilizing, reducing, dan proses calcining.

Multiple Hearth Roaster adalah besi berlapis yang tahan api, silinder vertikal bercangkang baja

ditempatkan pada Roaster berfungsi sebagai tungku refraktori.

Contoh penggunaan Multiple Hearthing Roasting Furnace

PENGOLAHAN ZINC

Mineral :

Sphalerite (ZnS), Franklinite (ZnO, MnO, Fe2O3). Kdr Zn pd ZnS sekitar 3%

PBG :

Differential FlotationPreparasi Kimia :

Roasting dilakukan pd flash roster, multiple hearth roaster mengubah sulfida menjadi oksida.

Diharapkan sulfida dpt direduksi dari 50% menjadi 8% saja.

ZnS +3/2O2 à ZnO + SO2

Preparasi Fisik:

Dialkukan sintering (digumpalkan) juga akan mereduksi S dr 8% mjd 1% saja.

Retorting:

Ada 2 mcm : vertical dan horizontal

Zinc akan melebur pd 419 C, mendidih 906 C sedang mereduksi dibutuhkan Temp 910-930 CReaksi :

ZnO + C à Zn + CO……..1

ZnO + CO à Zn+CO2…...2 

CO2 + C à 2CO…………3 

Hal2 yg perlu diperhatikan:

-Zinc mudah bereaksi dgn CO

-Pd T 1000 C, CO jmlnya sedikit

Reynold Kevin W.

1009045040

Metallurgy

7/27/2019 Multiple Hearthing Roasting Furnace Metalurgi

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EQUIPMENT - 3-FOOT-DIAMETER MULTIPLE-HEARTH FURNACE

A 3-foot inside diameter, eight-hearth roaster is available at Hazen for pilot-plant

thermal processing studies. Materials most suited for processing in this unit include

finely divided ores, and concentrates, samples with adhering characteristics, and

samples requiring combustion or pyrolysis over long residence times at controlledtemperatures (e.g. carbon activation).

The multiple-hearth furnace

is 4.5-feet in diameter by

6.5-feet high, and its

perimeter is lined with eight

inches of insulating

refractory. Hearth floors have

an average surface area of 

about 6.5 square feet. The

maximum operationalcapacity of the furnace is

about 8.7 cubic feet when

using a two-inch-deep bed on

51.7 square feet of hearth

floor. Rabble arms attached

to a central vertical shaft

agitate and move material

from each hearth to the next.

Both the vertical shaft and rabble arms are made of cast 309 stainless steel and

can be internally cooled with air, allowing operating temperatures up to 1000°C

(1850°F).

The multiple hearth is heated to operating temperature using gas burners mounted

on each of five different hearths, as shown in the schematic. Each burner has a

thermal capacity of 140,000 Btu per hour, providing an overall furnace capability of 

about 700,000 Btu per hour. Process temperature profiles are adjusted and

maintained with the use of the burners and secondary air adjustments. Steam or

reformed gas can be injected for gas atmosphere control. Flue gases from the

furnace are conveyed through an exhaust duct to a cyclone and baghouse for dust

removal. A scrubber is used for final gas cleaning before the gas is exhausted to the

atmosphere.

Feed rate and retention time can be varied to accommodate a wide range of 

operating conditions. Material is introduced using a variable-speed screw located

above the top hearth. Feed rates to the furnace range from 25 to 700 pounds per

hour, depending on the physical characteristics and processing requirements of the

material. Retention times can be controlled to range from 30 minutes to 12 hours.

Final product is discharged from the bottom hearth to a canister, to a four-inch

water-cooled screw, or to other solids-handling equipment.