What is a Bentonite Geosynthetic Clay Liner（GCL）

A. Definition

 Bentonite Geosynthetic Clay Liner（GCL）is a new type of geosynthetic material, mainly sodium bentonite particles evenly filled between two layers of geotextile (usually non-woven fabric and woven fabric), by needling, stitching or bonding and other processes made with waterproof blanket material. Through the characteristics of bentonite swelling in the water to achieve the purpose of waterproof waterproof seepage. Bentonite waterproof blanket is a kind of geosynthetic material specially used in artificial lake water features, landfill sites, underground garages, roof gardens, pools, oil depots and chemical storage yards.

（The picture shows a bentonite waterproof blanket）

B. Classification of bentonite waterproof blankets

C. Distribution of bentonite in China

1. Xinjiang

Hebuksel Mongolian Autonomous County: The bentonite reserves in the territory have exceeded 2.3 billion tons, which is the largest bentonite mining area in the country with proven reserves at present, and there are 7 bentonite deposits.

Qitai County: The No. Iii ore body of Xiheishan Bentonite Mine is located in the south of Kalamay Mountain system, the eastern margin area of Junggar Basin, and the geotectonic location is in the Kazakh-Junggar plate, Junggar-Tuha block and Junggar hidden microblock.

2. Guangxi

Ningming County: The bentonite deposit is a large deposit with a reserve of 610 million tons, which is one of the largest bentonite deposits in the world.

Tiandong County: The bentonite deposit is a medium-sized deposit.

3. Inner Mongolia

Guyang, Chifeng and Ningcheng areas in Baotou: Bentonite mineral resources in these areas are relatively rich, which provides an important resource base for the development of local bentonite industry.

4. The three northeastern provinces

Jiutai, Jilin Province: The bentonite has good quality and high practical value, and is one of the important bentonite producing areas in China.

Liaoning Heishan and Jianping areas: bentonite reserves are considerable, and the degree of exploitation and utilization is high. The local bentonite industry is relatively mature, and the products are widely used in many fields.

5. Other regions

Anhui: There is a super-large bentonite deposit in Xintan Township, Tunxi District, Huangshan City, that is, the Xintan bentonite deposit, with a cumulative proven bentonite ore reserves of 114 million tons.

Lin 'an, Zhejiang Province: Bentonite resources are relatively rich, and the local bentonite processing industry has developed well.

Henan Xinyang Pingqiao, Wulidian area: it is also one of the sources of bentonite.

In short, the wide distribution of bentonite in China is of great significance, which can ensure the raw material supply of casting, drilling mud, metallurgical pelletizing and other industries in the industry, promote the development of related industries, and improve product quality and production efficiency; In agriculture, soil structure can be improved, water and fertilizer retention ability can be improved, which is conducive to crop growth. In the field of construction, it helps to improve the performance of waterproof materials and ensure the waterproof quality of buildings; From the economic point of view, it promotes the development of industries related to resource exploitation and utilization, and increases employment and local fiscal revenue; From the resource strategy level, the domestic non-metallic mineral resource reserves are enriched, and the resource security and industrial development autonomy are enhanced.

D. Sodium modification of bentonite

  （As shown in the following picture）

E. Properties and functions of bentonite

1. Water absorption and expansibility

Bentonite is very absorbent and can absorb water several times its own weight. This is because montmorillonite can adsorb a large number of water molecules between crystal layers. This expansibility makes it play an important role in waterproof projects, such as bentonite waterproof blanket is to use this property to fill gaps and prevent water leakage.

2. adsorptivity

Bentonite has a large specific surface area, and has good adsorption capacity for various gases, liquids, organic and inorganic substances. It can absorb harmful substances like heavy metal ions (such as lead, mercury, cadmium, etc.), so it can be used in the field of environmental protection for wastewater treatment and soil remediation. In the feed industry, bentonite can also adsorb mycotoxins in feed, thereby improving the quality and safety of feed.

3. Suspension and dispersion

Bentonite can form a stable suspension in water. Its particles are small, can be evenly dispersed in water, and remain suspended for a certain period of time. This makes it widely used in coatings, ceramics, drilling mud and other industries.

4. Caking property

Bentonite has good bonding properties. When it is mixed with the right amount of water, other solid particles can be bonded together. In the casting industry, bentonite can be used as a binder to make sand mold, so that the sand particles are tightly bonded to ensure the strength and accuracy of the casting model. Bentonite is also an important binder in pellet production.

5. plasticity

Bentonite has good plasticity when mixed with appropriate amount of water. It can be kneaded into a variety of shapes like dough, and can maintain a certain shape after drying or firing. This has a certain application in the fields of ceramics and sculpture, and it can be used as an additive to ceramic billets, improve the plasticity of the billets, and make ceramic products easier to shape.

6. stability

Bentonite is chemically stable at room temperature. It does not undergo violent chemical reactions in the general acid-base environment and can maintain its own performance. This makes it stable in many long-term use scenarios such as the chemical industry and the construction industry. However, under extreme conditions of strong acids or bases, the structure of bentonite may be damaged to a certain extent.

7. Ion exchange property

There are exchangeable cations, such as sodium and calcium, between the montmorillonite crystal layers of bentonite. These cations can be exchanged with other cations in the solution. This ion exchange property makes bentonite used in soil improvement, detergent and other fields. For example, in soil improvement, bentonite can adsorb harmful ions in the soil through ion exchange, while releasing ions beneficial to plants, thereby improving soil fertility and structure.

F. Summarize

Bentonite Geosynthetic Clay Liner（GCL）is an excellent waterproof and impermeable material. It is mainly sodium bentonite as the key raw material, the use of acupuncture, acupuncture coating or adhesive and other advanced technology, bentonite particles properly placed between geotextile and non-woven fabric processing. Its unique feature is that sodium bentonite can expand several times to tens of times when exposed to water, forming a continuous, impervious gel, and forming a stable and efficient waterproof layer under the restriction of geotextiles. This waterproof blanket has excellent waterproof performance, can effectively block water penetration, and can adapt to complex geological conditions and construction environment. At the same time, it also has a certain degree of self-healing, when the waterproof layer is locally damaged, bentonite expansion in water can automatically fill the gap. In many engineering fields such as landfill sites, artificial lakes and underground buildings, bentonite waterproof blankets play a vital role, greatly reducing the risk of leakage and ensuring the safety and stability of the project. Bentonite waterproof blanket is of great national significance. In terms of environmental protection, the use of landfill can prevent leachate pollution of soil and groundwater, and protect the ecology. In water conservancy projects, the seepage prevention safety of reservoirs and DAMS should be ensured to reduce the waste of water resources. In the field of construction, improve the waterproof quality of basements, extend the life of buildings, and promote the development of national construction.