How to Choose Between Dry and Wet Grinding for Calcium Carbonate?

The selection of dry grinding or wet grinding for CaCO₃ (GCC/PCC) is determined by core product requirements (particlesize,dispersion, purity), end-use application, production cost, and process matching (e.g., subsequent surface modification)—this is the fundamental principle.

Dry grinding is the mainstream for conventional filler-grade CaCO₃ (cost-efficient, simple process), while wet grinding is the only viable industrial method for ultra-fine/nano CaCO₃ (D50 < 1 μm) with strict dispersion and particle size distribution requirements. A clear particle size boundary and application-driven performance demands are the key decision-making criteria, and the two processes have complementary advantages with almost no direct substitution in their core application scenarios.

Core Applicable Scope & Key Differentiation

First, the particlesize threshold is the most direct selection basis—this is the industrial consensus for CaCO₃ grinding, and other factors are secondary supplements:

Step-by-Step Selection Criteria (Industrial Practicability)

Follow this priority order to make decisions—no need for trade-offs in most cases; only the 0.5–1 μm submicron zone requires balancing cost and performance.

First: Determine the Target Particle Size (D50)

This is the one-step decision for most scenarios:

D50 ≥ 1 μm: Choose dry grinding—it is the most economic and efficient option; wet grinding has no cost or performance advantage here and is not recommended.

D50 < 1 μm: Must choose wet grinding—dry grinding cannot stably produce CaCO₃ with D50 < 1 μm in industrial batches (jet mill can reach submicron but has extremely high energy consumption, poor PSD, and serious agglomeration; not cost-effective).

D50 0.5–1 μm (submicron transition zone):

If dispersionrequirement is low (e.g., low-end plastic/rubber filler) and cost control is strict: Optimized dry grinding (jet mill + classification) is optional.

If dispersionrequirement is high (e.g., mid-end coating/paper coating): Wet grinding is the better choice (stable product quality, no post-grinding re-agglomeration).

Second: Combine End-Use Application & Product Performance Demands

Even for the same particle size, application-driven performance requirements will override cost considerations—critical for high-value-added CaCO₃ products:

Choose Dry Grinding If:

End applications: Low/mid-end plastic/rubber filler, paper bulk filler, building material additives, putty powder (no strict requirements for dispersion/PSD; cost is the core factor).

Process matching: Need integrated dry grinding + dry surface modification (the most common industrial combination for CaCO₃; shortens process, reduces intermediate handling, and lowers modification cost).

Site conditions: No wastewater treatment capacity, limited factory space, or small production scale (dry grinding has a compact layout).

Choose Wet Grinding If:

End applications: High-end liquid systems (water-based/oil-based coatings, inks, adhesives), high-performance plastics (nano CaCO₃ for toughening), papermaking coating pigment, cosmetics/food-grade CaCO₃ (strict requirements for dispersion, PSD, and purity).

Process matching: Need in-situ wet surface modification (modify CaCO₃ in slurry state; the modifier is uniformly adsorbed on particle surfaces without agglomeration; the modified slurry can be directly supplied to downstream liquid product production, saving drying costs).

Product form requirement: Need CaCO₃ slurry (direct supply to downstream coating/paper mills; avoids dry powder transportation and re-slurry preparation for customers).

Third: Evaluate Production Cost & Scale

Cost is the final check for the transition zone (0.5–1 μm) and non-mandatory wet grinding scenarios:

Large-scale production (≥10.000 t/a) of conventional filler-grade CaCO₃: Dry grinding is the only option (low unit cost, high production efficiency; wet grinding’s fixed investment and operation cost are not feasible).

Small-batch production of high-value-added ultra-fine/nanoCaCO₃: Wet grinding is acceptable (the high unit price of the product offsets the grinding cost; dry grinding cannot meet quality requirements).

Wastewater treatment cost: If the factory is in a region with strict environmental protection policies and high wastewater treatment costs, prioritize dry grinding for submicron products (if quality allows).

Key Supplementary Considerations for Industrial Application

GCC vs.PCCgrinding: PCC has a loose, porous structure and lower hardness than GCC; wet grinding of PCC requires lower energy consumption and can reach a smaller particle size (D50 < 0.1 μm) more easily; dry grinding of PCC is prone to severe agglomeration and is only suitable for coarse-grade products.

Post-grinding processing: Dry grinding powder can be directly mixed with modifiers for dry surface modification (the most common CaCO₃ modification process); wet grinding slurry can be subjected to wet surface modification (using water-soluble/oil-soluble modifiers) and then dried to obtain modified powder, or directly used as a slurry product (saves drying cost).

Particle size distribution(PSD): Wet grinding produces CaCO₃ with a narrower PSD (no large particles due to the liquid medium’s classification effect); dry grinding has a wider PSD (needs high-precision air classification to remove coarse particles, increasing additional cost).

Impurity removal: Wet grinding can realize in-situ impurity removal (e.g., magnetic separation, flotation) in the slurry state, which is more efficient than dry impurity removal; suitable for high-purity CaCO₃ production.

Summary of Quick Selection Guide

In short, dry grinding is the cost-effective choice for conventional CaCO₃, and wet grinding is the quality-mandatory choice for ultra-fine/nanoCaCO₃—the two processes are not competitive but form a complete industrial grinding system for CaCO₃ covering all particle size grades and application scenarios.