Slide 1
Extractive Metallurgy - IIHeat Balances in Process
MetallurgySchedule :Class A : Monday, 14.00-15.40Class B : Monday,
16.00-17.40
Course Content
Preface : PyrometallurgyThermodynamic Aspect of Pyrometallurgy
(I)Thermodynamic Aspect of Pyrometallurgy (II)Mass BalanceHeat
BalanceMass and Heat Balance Calculation in Pyrometallurgy
ProcessMid Semester ExaminationSlag and RefractoryPre-extraction
Process (Ore Preparation, Calcination)Reduction of Oxide
MineralsRefining of Crude MetalOxide Mineral Reduction &
RefiningThermodynamic Aspect of Sulfide Ore Processing Matte
Smelting-I (Extraction and Refining of Copper Sulphide Ore)Matte
Smelting-II (Nickel Matte Production)Final Examination
On calculation of process metallurgy, energy calculation is
needed besides of mass balance calculation. This problem can be
solved by calculate the heat balance.Langkah-langkah yang perlu
diperhatikan dalam melakukan perhitungan neraca panas adalah
sebagai berikut :Determine the calculation bases for each
reactant/product : it can be per-mole of reactant, per-weight of
product, etc
Create a mass balance for that process
Use a furnace as system in heat balance calculation. Endothermic
reaction = heat output for furnaceExothermic reactions = heat input
for furnace
Determine the reference temperature (25oC is used as common
temperature)
Determine a temperature of each feed/reactant and products.
Determine input and output heats based on the reactions.
(endothermic or exothermic)
Make an input and output heat table. You have to focus on total
heat in each section (deficient or excess heat)Cu2S + O2 + 3,76 N2
2 Cu + SO2 + 3,76 N2Cu2S[1300oC]O2 +
N2[25oC]N2[800oC]SO2[800oC]Cu[1250oC]
Cu2S 2 Cu + S H1 (298 K) = +a (endotermik)S + O2 SO2H2 (298 K) =
-b (eksotermik)Cu2S[1300oC]H (1573298) =-Cp dTO2 [25oC]H = 0N2
[25oC]H = 0N2 [800oC]H(2981073) =Cp dTSO2 [800oC]H(2981073) =Cp
dTCu [1250oC]H(2981523) =Cp dTTemperatur Referensi 298 K
Heat OutputHeat InputCu2SH (1573298) = Cp dTO2H(298298) =
0N2H(298298) = 0S + O2 SO2 H2 (298 K) = bHeat excess(output input)
= need ?
Limestone dengan komposisi 56% CaO dan 44% CO2 dikalsinasi di
dalam rotary kiln untuk menghasilkan CaO murni. Untuk setiap 1
kilogram limestone diperlukan 0,15 kg bahan bakar dengan komposisi
85% Karbon dan 15% Hidrogen, serta diperlukan 2000 Nm3 udara. Bahan
bakar terbakar secara sempurna dan bercampur dengan CO2 dari
limestone sehingga keluar bersama sebagai gas buang. Tentukan
apakah panas pada proses ini memadai dengan membuat neraca panas
proses.
(catatan : udara mengandung 21% gas oksigen dan 79% gas
nitrogen)
An iron ore containing 10% SiO2 and 3 % Al2O3 balance Fe2O3 is
smelted in an electric furnace with cokes and limestone. The ashes
in the coke are disregarded. The product iron contains 4%C and 1 %
Si. The slag has a ratio (wt% CaO/wt.% SiO2) = 1.1.
(a). On the basis 1 kg of hot metal calculate the weight and
composition of the slag.
(b). The furnace gas has a ratio CO2/CO = 0.2. Calculate the
necessary amounts of carbon and calculate the weight and volume
(STP) of the CO and CO2 gases.
(c). Make a heat balance of the process and calculate the
electric energy per kilogram of iron when the raw materials are
introduced at 250C, the slag and hot metal are withdrawn 14000C ,
and the gases at 1000C. The heat content relative to 250C, of the
hot metal is 1260 kJ/kg and of the molten slag is 1800 kJ/kg. The
solid slag may be regarded as mixture of CaSiO3, Ca2SiO4 and Al2O3.
The enthalpy of solution of Si in iron at 250C is 125 kJ/mol. Heat
losses are disregarded. Enthalpy of slag formation at 298 K is
about 40 kJ/0.3 mol CaO. The reduction reaction occurs during
smelting might be expressed as; Fe2O3 + 3C = 2Fe + 3 CO
