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WELCOME TO NAOSHIMA



Aerial View of Naoshima Smelter and Refinery		 Naoshima Smelter and Refinery is Mitsubishi Materials’ flagship smelter, and can trace its roots back to 1918 when operations first started using a reverberatory furnace. Naoshima is located in the middle of the scenic Seto Inland Sea National Park, and has strict environmental regulations.

In 1959, development of the Mitsubishi Process began, and in 1974 the first commercial scale Mitsubishi Process Smelter began operating in Naoshima with an anode production capacity of 48,000 t/y. This was doubled to 96,000 t/y in 1982, by increasing oxygen enrichment.

In 1991, the existing reverberatory + PS converter line and original Mitsubishi Process line were halted and consolidated into one new larger Mitsubishi Process line with production capacity of 204,000 t/y. This was subsequently increased to 240,000 t/y one year later. In 2000 with no change to furnace dimensions, but merely increasing oxygen enrichment, production was lifted above 270,000 t/y.

Naoshima continues to act as a vital resource to all other Mitsubishi operations in terms of furnace design, process data, plant practice and process control.

The main features of Naoshima's operations are:

The Mitsubishi Process Smelter Building at Naoshima


Naoshima' Smelter Control Room


Arrangement of the Mitsubishi Process Smelter at Naoshima

The figure below shows a detailed arrangement of the current Mitsubishi Process Plant and ancillary equipment at Naoshima.

1.Control Room
2.Compressor Room
3.Dryer
4.Bag House
5.Flux Receiving Hopper
6.Flux Bins
7.Feeding Tanks for Smelting Furnace
8.Smelting Furnace
9.Slag Cleaning Furnace
10.Converting Furnace
11,12.Boilers
13.Electrostatic Precipitators
14.Discard Slag Granulation Pit
15.Slag Bin
16.Pressed Scrap Conveyor
17.C-Slag Dryer
18.C-Slag Granulation Pit
19.Anode Scrap Conveyor
20.Anode Furnaces
21.Casting Wheel


Operating Parameters

The table below shows a comparison between initial design and current operating parameters of Naoshima's Mitsubishi Process Smelter.

Design Current
S Furnace
Concentrates
Coal
Return C-slag
T/H
T/H
T/H
85.0
2.3
7.0
91.3
3.0
10.0
Lance Blowing Rate
Air
80% O2
Total
O2 enrichment
Nm3/h
Nm3/h
Nm3/h
%		 24,000
16,100
40,100
45.0		 13,900
18,800
32,700
55.2
C Furnace
Matte
Anode scrap
Return C-slag
T/H
T/H
T/H
43
4.6
2
56.8
5.0
18.5
Lance Blowing Rate
Air
80% O2
Total
O2 enrichment
Nm3/h
Nm3/h
Nm3/h
%		 19,700
4,300
24,000
32.0		 22,500
7,500
30,000
36.2
Offgas
S-furnace

C-furnace
DNm3/min
SO2%
DNm3/min
SO2%
620
30.0
390
27.0
500
37.7
480
28.0
Anode Production
from concentrate
from scrap
T/Y
T/Y
192,000
12,000
265,000
13,000
Total production
(from new source)		 T/Y 204,000 278,000



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