- Manual Lining

• • Bottom Lining

Provide ramming workman with face-mask.

Check that the fork-rammer prongs are sharp, long and well spaced, Blunt and worn tools are the commonest cause of poor compaction. The fork should be at least 4” to 5” long.

Carefully place 100mm layer of premixed ramming mass on the furnace bottom with buckets. Avoid dropping from height as fine particles and binder may fly out. Ram with fork-rammer at the rate of 40 man minutes per square meter. This allow entrapped air to escape, so that finer particles can settle into space between larger ones to give a compact lining, add further premixed ramming mass in 50mm layers and fork ram again. Ram for more time on the upper layers than the lower ones. Once you have reached the topmost level of the bottom, ram with round rammer to get a hard surface. Make sure that the bottom is flat with the help of a spirit level as otherwise the former will not sit straight and you will have variable lining thickness.

Important: Do not use round rammer in between layers while bottom ramming is being done.

• • Placing the former

The weld joints in the former should be flattened by grinding in order to avoid hot spots. The outside and inside of the former should be cleaned with compressed air or clean dry cloth. If rusty, sand it down well. Holes in the former should be of 3mm diameter. and about 200mm apart. Before inserting the former into the furnace its bottom and sides should be cleaned with ramming mass to get rid of any dirt. The former should be position as close to the centre as possible using a hoist/crane. Just before the former rests on the bottom, read just it manually. Avoid moving it about too much or it may disturb the bottom lining. Hold the former firmly centred with at least three wooden wedges and do not remove the wedge till half of the side is rammed.

• • Side wall lining

The rammed bottom portion around the former should be rammed thoroughly (only for about 5 mins with a fork rammer . This should be done without disturbing the rest of the bottom lining. This is done so that the bottom portion and the sidewalls of the lining hold together properly and form a single mass on sintering.

The ramming mass is then charged into the space around the former using a funnel with a long stem. The use of the funnel will prevent the fine particles and binder from being blown away. The ramming mass is to be added in layers of 20 mm height and rammed using fork only. Special care is to be taken while ramming near the tapered portion of the former. Here a 4 man team can ram for 10 minutes in this portion.

Once the taper portion is rammed, ramming mass can be added in layers of 40mins and a 4 man team can ram for 5 minutes. This way the side lining is to be completed all the way to the top of the furnace. Please note that round rammer is not to be used when the sidewall is being rammed. Use the round rammer only at the top using 4 men for 10 minutes.

Now the ramming is complete and you can start the sintering process.

- Lining with Daka Indcross Vibrator

• • Bottom Lining

Provide ramming workman with face-mask.

Carefully place premixed ramming mass on the furnace bottom with buckets till top as per lining specifications by furnace manufacturer. Avoid dropping from height as fine particles and binder may fly out. Now place bottom plate of Daka Indcross Vibrator onto the furnace bottom. Start the vibration by providing 30 bars of air pressure in pneumatic motor. This allow entrapped air to escape, so that finer particles can settle into space between larger ones to give a compact lining. Provide vibrations for minimum 10 minutes and maximum of 15 minutes. Make sure that the bottom is flat with the help of a spirit level as otherwise the former will not sit straight and will have variable lining thickness on side wall.

• • Placing the former

The weld joints in the former should be flattened by grinding in order to avoid hot spots. The outside and inside of the former should be cleaned with compressed air or clean dry cloth. If rusty, sand it down well. Holes in the former should be of 3 mm diameter. and about 200 mm apart. Before inserting the former into the furnace its bottom and sides should be cleaned with ramming mass to get rid of any dirt. The former should be position as close to the centre as possible using a hoist/crane. Just before the former rests on the bottom, read just it manually. Avoid moving it about too much or it may disturb the bottom lining. Hold the former firmly centred with at least three wooden wedges and do not remove the wedge till half of the side is filled.

• • Side wall lining

The rammed bottom portion around the former should be rammed thoroughly (only for about 5 mins with a fork rammer . This should be done without disturbing the rest of the bottom lining. This is done so that the bottom portion and the sidewalls of the lining hold together properly and form a single mass on sintering.

The ramming mass is then charged into the space around the former using a funnel with a long stem. The use of the funnel will prevent the fine particles and binder from being blown away. The ramming mass is to be added till the top of the lining. Now place cross of Daka Indcross Vibrator into the former. Start tightening the cross using hydraulic pump provided. Put wooden battens into former between cross sections before fully tightening. Start the vibrations by providing 30 bars of air pressure in pneumatic motor. This allow entrapped air to escape, so that finer particles can settle into space between larger ones to give a compact lining. You will notice that slowly ramming mass will start to settle and will go down. Add some material till the top level of former. Provide vibrations for minimum 10 minutes and maximum of 15 minutes. Now loose the cross by reversing hydraulic pressure and remove the cross from former

Now the ramming is complete and you can start the sintering process

For sintering the lining the temperature of the sintering charge is to be increased at following rates

- With Boron Oxide as Binder

At rate not exceeding 200°C per hour upto sintering temperature which is 50°C above tapping temperature and hold for 1 hour.

- With Boric Acid as Binder

At rate not exceeding 100°C per hour upto 1300°C and hold for 1 hour and continue with 200°C per hour upto sintering temperature which is 50°C above tapping temperature and hold for 1 hour.