Tank Bottom Paving Wear

Glass Tank Wall · Bottom

Problem Details

Background

The glass furnace tank bottom holds static and flowing glass melt. The paving joints and castable leveling layer contact glass melt around 1500℃ for long periods. Melt penetration and attack on the bottom—especially "upward drilling"—is the main bottom failure mode, directly affecting furnace safety and campaign life.

Failure Mechanism

Melt penetration: glass melt penetrates downward along paving joints and pores, reacting with the underlying castable into an altered layer. Upward drilling: penetrated melt reacts with refractories into low-density phases that "drill upward" under temperature and buoyancy, gradually hollowing the bottom structure. Joint attack: paving joints are the preferred penetration path; over-wide joints or mismatched mortar worsen attack. Temperature effect: higher melt temperature and fluidity increase penetration and erosion.

Consequences

Upward drilling is the most dangerous bottom failure: it shortens furnace life at best, and at worst melt breaks through the bottom in a breakout that endangers personnel and causes huge economic loss.

Solution

Material Selection and Parameters

Design the tank bottom as a two-layer "leveling + paving" structure:

Leveling layer: corundum castable leveling (Al₂O₃≥90%), cast monolithically with a flat surface, providing a stable base for paving bricks and blocking penetration;
Paving layer: fused-cast AZS bricks with extreme density (apparent porosity ≤2%) and outstanding melt resistance; pave tightly with staggered joints;
Joint material: fill joints with high-performance mortar matching the brick or glass sealant to eliminate penetration paths.

Installation Essentials

Monolithic leveling: cast the corundum leveling layer monolithically with full vibration and a flat finish. Paving: lay bricks per design with staggered joints, uniform joint width and dense fill. Bake-out: heat slowly per the bottom curve to prevent steam spalling of the leveling layer. Acceptance: check paving flatness and joint fullness after placement.

Maintenance

Control melt temperature within process range to avoid prolonged over-temperature; monitor bottom temperature and breakout signs (abnormal bottom temperature rise) and plan repairs promptly on anomalies; at mid-campaign maintenance, inspect paving bricks and leveling layer and patch local damage.

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