Introduction to the Hydrated Lime Mill (Calcium Hydroxide Mill)

The KX Hydrated Lime Mill (also known as the calcium hydroxide grinding mill) is a specialized grinding equipment developed by Guilin Mining Machinery to overcome the technical challenges of calcium hydroxide (Ca(OH)₂), such as its light weight, easy adsorption, and strong stickiness. Based on the Raymond mill, it features improvements to the main unit’s grinding chamber geometry, shovel blade structure, and fan system. Integrating dispersion, grinding, and classification into one unit, it effectively solves problems such as adhesion, clogging, and low efficiency that commonly occur when processing calcium hydroxide with ordinary mills. It is the preferred equipment for producing high-quality (high fineness, high specific surface area) calcium hydroxide powder.

Features and Advantages of the Hydrated Lime Mill

Structural Features

• Grinding System: An internal disperser is integrated to preliminarily disperse calcium hydroxide that has uneven moisture content, agglomerates, or higher hardness after hydration. The shovel blade angle and structure have been improved to more effectively break up sticky and wet materials, preventing bottom accumulation. The grinding components consist of specially surface-treated reinforced grinding rollers and anti-stick grinding rings, overcoming the material adhesion problem. The internal chamber features a specially designed curved profile that works with the internal airflow to prevent material clogging at the source.
• Classification System: Pneumatic optimization of the flow path, anti-stick surface treatment, and high-level sealing technology work together with the fan system for airflow dispersion, solving the problems of easy agglomeration and adhesion during calcium hydroxide classification.
• Collection & Dust Removal System: Uses a cyclone collector and a pulse jet bag filter. The filter is equipped with anti-stick membrane filter bags to prevent bag hardening, and an airlock discharge valve to prevent air leakage that would affect collection efficiency.
• Fan & Duct System: Uses a high-pressure fan as the system power source. Air volume and pressure are precisely calculated and matched to create a directional airflow that reduces adhesion of calcium hydroxide on the surfaces of grinding components. The inner walls of the ducts are smoothed to ensure unobstructed airflow.

Performance Advantages

• Anti-Stick Design: To address the strong adhesiveness of calcium hydroxide, the hydrated lime mill features anti-stick treatment on components such as the grinding chamber, classifier, and dust collector, eliminating material adhesion and hardening, and ensuring long-term stable operation.
• Triple Dispersion: Triple dispersion technology precisely solves the problem of easy agglomeration and clogging of calcium hydroxide. An internal disperser provides preliminary dispersion of agglomerated material. The optimized shovel blade structure efficiently breaks up the material. The classification system and fan system work together for airflow dispersion.
• High Quality & High Output: Unit output is 15–30% higher than that of a Raymond mill. The finished calcium hydroxide powder has high activity, with advantages such as high fineness and high specific surface area.
• High Efficiency & Eco-Friendly: Uses a cyclone collector and a pulse membrane filter bag dust collector, together with an airlock discharge valve. Total powder recovery rate ≥99.9%, and dust emission concentration far exceeds (i.e., is much lower than) national standards.

Process Flow of the Hydrated Lime Mill

Hydrated calcium hydroxide → Feeder → Hydrated Lime Mill → Cyclone Collector → Pulse Membrane Bag Filter → Airlock Discharge Valve → Finished Product Packaging

Feeding & Dispersion

Hydrated calcium hydroxide is fed into the hydrated lime mill by a feeder. An internal disperser first performs preliminary dispersion of lumpy or agglomerated calcium hydroxide, reducing the load on subsequent processes. The material then falls onto a rotating disk, where it is thrown by the shovel blade into the grinding zone formed by the grinding rollers and grinding ring. The material is further broken up by collision under centrifugal force.

Измельчение и классификация

The material lifted by the shovel blade enters the grinding zone composed of specially treated reinforced grinding rollers and anti-stick grinding rings for grinding and crushing. Then, the rising airflow generated by the high-pressure fan passes through the entire grinding chamber, providing airflow dispersion of the material and effectively preventing secondary agglomeration of calcium hydroxide.

After thorough dispersion, the calcium hydroxide powder is sent to the classifier for precise separation. Qualified fine powder passes through, while unqualified coarse powder returns for regrinding, forming an efficient, stable, and anti-stick closed-circuit grinding system.

Сбор и удаление пыли

Both the cyclone collector and the pulse membrane bag filter are equipped with airlock discharge valves at the bottom. While maintaining stable negative pressure in the system, they continuously and efficiently collect the finished calcium hydroxide powder. Collection efficiency ≥99.9%, and emission concentration far exceeds (i.e., is much lower than) national standards.

Technical Parameters of the Hydrated Lime Mill

GK Hydrated Lime Mill Specification Table

Примечание: Приведенные выше данные являются справочными. Фактические параметры зависят от сырья. Пожалуйста, свяжитесь с нами для получения профессионального индивидуального решения.

Frequently Asked Questions about the Hydrated Lime Mill

What are the differences between a hydrated lime mill and a Raymond mill?

• Hydrated Lime Mill: Specifically designed for calcium hydroxide. Features a dispersion function to effectively prevent adhesion and clogging. The finished powder has high porosity, good activity, and relatively high specific surface area.
• Raymond Mill: Suitable for a wide range of materials. The finished powder is mostly flaky or granular, with uniform particle size but relatively low specific surface area.

Can the hydrated lime mill grind calcium oxide (quicklime) or other materials?

The hydrated lime mill is designed for grinding hydrated calcium hydroxide. It is strictly forbidden to directly grind raw calcium oxide (quicklime), as quicklime reacts violently with water vapor, posing an explosion risk. For other materials, the hydrated lime mill can also process some low to medium hardness (Mohs hardness ≤5) light materials with certain stickiness (e.g., kaolin, talc, barite), but its efficiency is lower than that of a Raymond mill.

Which manufacturer makes the best hydrated lime mill?

The hydrated lime mill is a specialized equipment improved from the Raymond mill to address the easy adhesion and moisture absorption characteristics of calcium hydroxide. Therefore, when choosing a hydrated lime mill, you should evaluate the manufacturer’s expertise in both Raymond mill technology and calcium hydroxide processing. Guilin Mining Machinery (GK) is undoubtedly an excellent choice. With 50 years of focus on powder processing, deep expertise in Raymond mill technology, and being one of China’s top 10 recommended Raymond mill brands, GK also holds multiple patents for calcium hydroxide processing. The GK Hydrated Lime Mill is wear-resistant and corrosion-resistant, with adjustable fineness from 80 to 400 mesh (95% passing through 325 mesh). It can also be flexibly equipped with a calcium hydroxide classifier to produce high-purity, high-fineness, high-specific-surface-area calcium hydroxide powder.

Why does the hydrated lime mill use a pulse membrane filter bag dust collector?

The hydrated lime mill uses a pulse membrane filter bag dust collector to handle the high humidity and strong stickiness of calcium hydroxide. A smooth ePTFE microporous membrane is laminated onto the surface of the ordinary filter bag, achieving surface filtration to capture dust and enabling ultra-low emissions of ≤10 mg/m³. Compared with ordinary filter bags, it offers longer service life, reduced filtration air velocity by 0.6–1.0 m/min, and advantages such as low operating resistance, strong cleaning capability, and high anti-stick performance. Ordinary pulse jet bag filters often struggle with difficult cleaning, bag blinding, and hardening when processing sticky and wet materials.