Installing refractory in a vertical grinding mill

Vertical grinding mills are widely used in the mining, cement, and steel industries for the grinding of various materials. The installation of refractory in a vertical grinding mill is essential to line the internal components that are exposed to high temperatures and abrasive materials. Refractory materials are chosen for their high thermal resistance and ability to withstand the harsh conditions within the mill.

1. Preparation:

a. Mill Inspection: Before installing new refractory, it is crucial to inspect the existing lining and assess its condition. Remove any damaged or loose refractory pieces and clean the surface to ensure a suitable bonding surface.

b. Surface Preparation: The mill liners should be thoroughly cleaned and prepared. Any rust, scale, or old refractory residue should be removed using suitable abrasive blasting techniques. The surface should be ground smooth to ensure proper adhesion of the new refractory.

c. Primer Application: Apply a suitable refractory primer to the cleaned and prepared surface. The primer will improve the adhesion between the refractory and the mill liner, ensuring a strong and durable bond.

2. Refractory Installation:

a. Material Selection: Choose the appropriate refractory material based on the operating conditions of the vertical grinding mill. Common materials include high-alumina bricks, chrome-magnesia bricks, and silicon carbide bricks. The material should be selected for its resistance to abrasion, thermal shock, and chemical corrosion.

b. Brick Layout: Plan the brick layout to ensure even distribution of the refractory material and to minimize the number of joints. The bricks should be laid in a staggered or random pattern to reduce the risk of thermal stress cracking.

c. Installation Techniques:

i. Mortar Application: Apply a suitable refractory mortar to the bottom of each brick and firmly place it in position. Ensure that the bricks are level and aligned with the existing lining.

ii. Spacer Installation: Install spacers between the bricks to maintain the desired thickness and prevent the bricks from contacting each other. Spacers can be made of metal or refractory materials and should be securely fixed in place.

iii. Grouting: Once the bricks are in place, fill the gaps between them with a refractory grout. The grout should be allowed to cure and harden before the mill is put back into operation.

3. Maintenance:

a. Regular Inspection: Regularly inspect the refractory lining to check for any signs of damage, such as cracks, chips, or excessive wear. Prompt repairs or replacement of damaged bricks will help extend the lifespan of the lining.

b. Cleaning and Repairs: If the refractory lining becomes dirty or contaminated, it should be cleaned using suitable abrasive blasting techniques. For minor repairs, such as filling in cracks or replacing loose bricks, follow the same installation procedures mentioned above.

c. Replacement: If the refractory lining is severely damaged or worn out, it may need to be replaced. This process involves removing the old lining, cleaning the surface, and installing new refractory bricks and mortar.

The installation of refractory in a vertical grinding mill is a critical process for ensuring the efficiency and longevity of the mill. By following the proper preparation, installation techniques, and maintenance procedures, operators can achieve a durable and effective refractory lining that can withstand the demanding conditions within the mill. Regular inspection and timely repairs or replacements will help maximise the lifespan of the refractory lining and minimise downtime in the grinding process.