Industry Solutions

A large alumina plant in Guangxi suffered severe failures on the mechanical seals of its two-stage series pumps handling high-solid, high-head slurries. The original seals experienced serious slurry leakage within just a few days to ten days of operation. Inspection revealed heavy wear on the cemented carbide rings. Several other seal manufacturers were engaged but failed to resolve the leakage issue, causing severe disruptions to production. The plant then turned to our company for assistance.

After analyzing on-site operating parameters and equipment performance, it was determined that the pump is a two-stage series unit with a single-stage head of 93 m and a combined head of nearly 200 m. It handles large-particle red mud slurry with a solid content as high as 600 g/L, driven by a six-pole motor at 980 r/min, representing extreme operating conditions. The original non-balanced seal design, combined with insufficient flush water pressure, led to unstable operation and rapid wear of sealing faces once slurry ingressed.

We carried out a full redesign and optimization: adopting a balanced structure capable of withstanding bidirectional pressure, using high-hardness, corrosion-resistant integrally pressureless sintered silicon carbide for sealing rings, improving the on-site flushing water circuit, and increasing water pressure to enhance face closing stability.

Following the comprehensive upgrade, the service life of the mechanical seals was drastically extended from just 10 days to more than 9 months. This ensured stable production for the customer and established a long-term, reliable partnership.