Geotextiles and Geomembranes in the Salt Chemical Industry: Applications and Solutions

The salt chemical industry presents a highly corrosive and demanding environment where the integrity of containment systems is paramount. Geosynthetics, specifically geotextiles and geomembranes, play a critical role in enhancing efficiency, durability, and environmental protection in salt production facilities. This article explores their key applications within various operational scenarios.

1. Crystallization Pond Liners: The Foundation of Salt Purity and Yield

The heart of any saltworks is its network of crystallization ponds. Here, the primary challenge is to prevent brine from seeping into the underlying soil, which leads to significant product loss and potential groundwater contamination.

• Application: A composite liner system is deployed, consisting of a geomembrane (typically HDPE for its excellent chemical resistance) as the impermeable barrier, underlain and overlain by geotextiles.

• Role of Geomembrane: The geomembrane acts as a high-performance impermeable layer, ensuring that the concentrated brine is effectively contained within the pond. This maximizes salt yield and purity by preventing contamination from subsoil minerals.

• Role of Geotextiles:

  • Cushioning (Above the geomembrane): A non-woven geotextile is placed over the geomembrane to protect it from puncture and abrasion caused by salt crystals, equipment traffic, and installation activities.

  • Protection & Drainage (Below the geomembrane): A geotextile layer beneath the geomembrane protects it from sharp protrusions in the subgrade and can also facilitate the drainage of any underlying gases or moisture.

2. Brine Pond and Reservoir Containment: Securing the Raw Material

Brine storage ponds and reservoirs hold the raw material for salt production. Their integrity is crucial for maintaining sufficient feedstock and preventing environmental seepage.

• Application: Similar to crystallization ponds, these containment areas utilize a geomembrane liner as the primary fluid barrier.

• Role of Geomembrane: It provides a robust and chemically resistant seal to prevent brine loss and protect the surrounding soil and groundwater.

• Role of Geotextiles: Geotextiles are used in conjunction with the geomembrane as a protective cushioning layer, extending the liner’s service life by mitigating installation and operational stresses.

3. Protective Underlayment for Salt-Sunning Mats: Enhancing Durability

Traditional salt-sunning mats or plastic sheets used to facilitate evaporation can be vulnerable to punctures and damage from the uneven or rough subgrade.

• Application: A layer of non-woven geotextile is deployed directly on the prepared subgrade before laying down the salt-sunning mats or flexible geomembrane sheets.

• Role of Geotextile: The geotextile acts as a versatile protective cushion. It distributes localized stresses, prevents puncture of the overlying impermeable layer by sharp particles, and allows for the passage of water vapor, helping to maintain a stable base. This significantly extends the service life of the primary containment layer and reduces maintenance costs.

4. Filtration and Separation in Drainage Systems

Managing water around evaporation ponds is essential. Drainage ditches and channels require filtration to prevent soil erosion and clogging.

• Application: Woven or non-woven geotextiles are used as filter fabrics in drainage channels and around pipework.

• Role of Geotextile: The geotextile acts as a permeable separator, allowing water to pass while preventing fine soil particles from migrating into the drainage aggregate. This maintains the efficiency of the drainage system and ensures structural stability.

Conclusion: An Integrated Geosynthetic Solution

The synergistic use of geotextiles and geomembranes is fundamental to modern, efficient, and environmentally responsible salt production. Geomembranes provide the essential function of impermeable containment, directly contributing to higher yield and environmental compliance. Geotextiles, in their roles as protection, cushioning, and filtration layers, are indispensable for ensuring the long-term performance and durability of the entire containment system. By selecting the appropriate geosynthetic products and design, salt chemical operations can achieve significant operational and economic advantages.