Core Differences Between Sodium Bentonite and Calcium Bentonite
1.Chemical Composition
Sodium Bentonite: Dominated by montmorillonite, with sodium ions (Na⁺) as the main interlayer cation.
Calcium Bentonite: Also montmorillonite-based, with calcium ions (Ca²⁺) as the main interlayer cation。
2.Water Absorption & Swelling Performance
Sodium Bentonite: High water absorption (over 500% of its dry weight), swelling ratio reaches 20-30 times, fast hydration and high viscosity.
Calcium Bentonite: Low water absorption (≤200%), swelling ratio is only 2-10 times, slow hydration and poor viscosity.
3.Process & Production
Sodium Bentonite: Rare natural reserves, most products are modified from calcium bentonite via sodium ion exchange, requiring extra processes like soda ash addition and 3-7 days of aging.
Calcium Bentonite: Abundant natural reserves (accounting for 80% of China's total bentonite), can be directly produced after simple crushing and drying, no chemical modification needed.
4.Application Scenarios
Sodium Bentonite: High-end scenarios such as drilling mud, pile foundation engineering, landfill anti-seepage, high-grade coating thickening, and precision casting.
Calcium Bentonite: Low-cost general scenarios, including ordinary putty, low-end coatings, feed additives, and simple soil improvement.
5.Price & Cost
Sodium Bentonite: Higher production cost, market price is significantly higher than calcium bentonite.
Calcium Bentonite: Simple process and low cost, with obvious price advantage in low-demand scenarios