Gypsum is a foundational material in the modern construction industry. You can find it everywhere, from the walls of your home to the plaster in art studios. As a manufacturer of mineral processing equipment at ZONEDING, we have helped clients worldwide set up efficient gypsum production lines. Understanding the journey from a simple rock to a valuable powder is the first step in starting a successful operation. This guide will walk you through the entire process, explaining each stage and the equipment you need to transform raw gypsum into a final, marketable product.

Table of Contents

• What is Gypsum?
• What are Types of Gypsum?
• What is Gypsum Used For?
• Why Do We Need to Process Gypsum?
• What is the Process of Gypsum Production?
• Which Equipment do You Need in a Gypsum Production Line?
• What is the Difference Between Natural and FGD Gypsum Production?
• What are the Key Factors Affecting Gypsum Price?
• How To Choose Good Quality Gypsum?
• How Do You Control the Quality and Setting Time of Gypsum Powder?
• Conclusion
• FAQ

What is Gypsum?

Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate. Its chemical formula is CaSO₄·2H₂O. This means each molecule of calcium sulfate is bonded with two molecules of water. This water is a key part of its chemistry and is crucial for the gypsum calcination process. You can find gypsum in nature as large, sedimentary rock deposits. But It often forms when saltwater lakes or seas dry up. And The mineral is typically white, colorless, or gray it can also be found in shades of pink, yellow, or brown due to impurities. It is very soft and can be easily scratched with a fingernail.

What are Types of Gypsum?

At ZONEDING, we deal with two main types of gypsum. The first is natural gypsum, which is mined directly from the earth. The second is synthetic gypsum, often called FGD gypsum, which is a byproduct of industrial processes like flue-gas desulfurization in coal-fired power plants. Both can be processed into high-quality products, but they require slightly different approaches and equipment.

What is Gypsum Used For?

The uses of gypsum are incredibly diverse, but they are dominated by the construction industry. The unique ability of its calcined form (Plaster of Paris) to harden after being mixed with water makes it extremely valuable.

The main application of gypsum is manufacturing drywall, also known as plasterboard or wallboard. Over 75% of all processed gypsum goes into making these panels that form the interior walls and ceilings of buildings worldwide. Its other applications are also very important for various industries.

Industry	Application	Why Gypsum is Used
Construction	Drywall, Plaster of Paris, Stucco, Building Plasters	It is lightweight, easy to work with, provides a smooth finish, and offers fire resistance.
Cement	Additive in Portland Cement	It acts as a retarder, controlling the setting time of the concrete. Without gypsum, concrete would set too quickly.
Agriculture	Soil Conditioner (“Land Plaster”)	It improves soil structure, helps with water infiltration, and provides calcium and sulfur, which are essential nutrients for plants.
Other Uses	Molds for pottery, surgical splints, food additive	Its ability to form a hard, stable shape when set is used in many different fields.

Why Do We Need to Process Gypsum?

Raw gypsum rock is useful, but its true economic potential is unlocked through processing. The primary reason we process gypsum is to change its chemical structure through a process called calcination. This process is what gives gypsum its magical property of being able to set and harden.

The goal is to heat the gypsum to drive off about 75% of its bonded water. This transforms the calcium sulfate dihydrate (CaSO₄·2H₂O) into calcium sulfate hemihydrate (CaSO₄·½H₂O). This new substance is what we commonly know as Plaster of Paris. When you add water back to this powder, it rehydrates, crystallizes, and quickly turns back into a hard, solid mass of dihydrate gypsum. This reversible chemical reaction is the foundation of the entire gypsum industry. At ZONEDING, we design gypsum processing plants specifically to control this transformation perfectly.

What is the Process of Gypsum Production?

A complete gypsum production line involves several key stages. Each stage requires specific machinery to reduce the size of the rock and then alter its chemistry. The process is straightforward and can be broken down into four main steps.

1. Mining and Extraction

The process begins at the quarry. Gypsum is typically mined in open-pit mines. Large excavators and trucks are used to extract the raw gypsum rock from the deposit. The size of these rocks can be very large, often over 500mm, which is too big for any processing equipment.

2. Crushing

The large rocks from the mine are transported to the crushing stage. This is the first step in size reduction.

• Primary Crushing: A Jaw Crusher is almost always used for this first step. It takes the large feed rock and breaks it down to a more manageable size, usually around 100-150mm.
• Secondary Crushing: The smaller rocks then go to a secondary crusher, often an impact crusher or a hammer crusher. This machine breaks the rock down further into small pieces, typically less than 50mm.

3. Grinding

After crushing, the gypsum pieces are still too large for efficient calcination. The material is fed into a grinding mill to be turned into a fine powder. A Ball Mill or a Raymond mill is commonly used. The goal is to produce a consistent, fine powder (around 100-200 mesh). This fine powder has a large surface area, which allows it to be heated evenly and quickly in the next stage.

4. Calcination

This is the most critical step in the entire process. The fine gypsum powder is fed into a calciner, which is usually a large Rotary Kiln. Inside the kiln, the powder is heated to a precise temperature, typically between 140°C and 180°C. This controlled heating removes most of the water of crystallization, creating the final product: Plaster of Paris.

Which Equipment do You Need in a Gypsum Production Line?

To build a full gypsum processing plant, you need a series of machines that work together in a continuous flow. As a manufacturer, we at ZONEDING provide the entire suite of equipment required.

• Feeding and Conveying Equipment: This includes vibrating feeders to feed the raw rock into the crusher and belt conveyors to transport material between each stage.
• Crushing Equipment:
  • Jaw Crusher: For primary crushing of large rocks.
  • Impact Crusher or Hammer Mill: For secondary, finer crushing.
• Grinding Equipment:
  • Ball Mill or Raymond Mill: To grind the crushed gypsum into a fine powder.
• Calcination Equipment:
  • Rotary Kiln: The core machine for heating the gypsum powder. This is often the most significant investment in the gypsum production line cost.
• Auxiliary Equipment:
  • Dust Collectors: To control air pollution and capture fine product.
  • Storage Silos: To store the raw material and the final gypsum powder product.
  • Packing Machine: To package the final powder for sale.

What is the Difference Between Natural and FGD Gypsum Production?

While the final product can be very similar, the starting point for natural and FGD (Flue-Gas Desulfurization) gypsum is different, which affects the production line.

• Natural Gypsum: This is mined rock. It is hard, lumpy, and has low moisture content. It requires the full process: primary crushing, secondary crushing, grinding, and calcination.
• FGD Gypsum: This is a synthetic byproduct from power plants. It is already a fine powder, but it has a very high moisture content (often over 15%). Therefore, an FGD gypsum processing line does not need a crusher or a grinder. However, it requires a large, efficient dryer to remove the surface moisture before the material can be calcined. In many ZONEDING plant designs, the drying and calcination happen in a single, specially designed kiln.

What are the Key Factors Affecting Gypsum Price?

The gypsum price per ton can vary based on several market and production factors. If you plan to sell gypsum powder, you need to understand these factors.

• Purity: The higher the percentage of CaSO₄·2H₂O, the more valuable the gypsum. High-purity gypsum is white and preferred for applications like plaster and medical uses.
• Location and Logistics: Gypsum is a high-volume, relatively low-value material. Transportation costs can be a significant part of the final price. A plant located far from its market will have higher costs.
• Energy Costs: The calcination process requires a lot of heat, which means burning fuel (like coal, natural gas, or oil). The local cost of energy will directly impact your production cost and selling price.
• Market Demand: The demand for gypsum is closely tied to the health of the construction industry. During a construction boom, prices will rise.

How To Choose Good Quality Gypsum?

Whether you are buying raw gypsum rock or selling finished powder, quality is key. Here is what to look for:

• High Purity: Look for gypsum with a purity level above 90%. Impurities like clay, salt, and limestone can affect the final product’s performance.
• Whiteness: For applications where appearance matters (like plaster or fillers), a high degree of whiteness is desirable.
• Low Chloride Content: High salt (chloride) content can cause issues like corrosion of metal fasteners in drywall and affect the setting properties.
• Consistent Particle Size: For finished powder, a consistent particle size ensures predictable setting times and a smooth finish.

How Do You Control the Quality and Setting Time of Gypsum Powder?

Controlling the final product quality happens during the production process. The most important variable to control is the calcination stage.

The key is precise temperature and time control in the rotary kiln.

• Under-calcination: If the temperature is too low or the time is too short, not enough water is removed. The resulting powder will be weak and have a slow setting time.
• Over-calcination (“Dead-Burning”): If the temperature is too high (above 200°C), all the water is removed, creating anhydrite (CaSO₄). This “dead-burned” gypsum will not set or harden when water is added.

At ZONEDING, our modern gypsum production lines include advanced control systems that monitor the temperature inside the kiln in real-time. This allows operators to make fine adjustments to the fuel flow and kiln rotation speed, ensuring every particle of gypsum is perfectly calcined. This level of control guarantees a consistent final product with a predictable setting time.

Conclusion

Gypsum production is a process of transforming a common rock into an indispensable industrial product. The journey involves powerful crushing, fine grinding, and a precise chemical transformation through heat. With the right equipment and process control, you can produce high-quality gypsum powder for a wide range of profitable applications.

At ZONEDING, we are more than just an equipment supplier; we are your partner in building a successful gypsum processing plant. Because we are a factory-direct manufacturer, we control the quality of every machine we build and can offer you a competitive price by eliminating middlemen. Our team of experienced engineers will work with you to design a customized production line tailored to your specific raw material and output goals. From initial design and manufacturing to on-site installation and training, we provide a complete, one-stop solution to get your operation running efficiently.

Contact us today to discuss your project and get a custom quote for your gypsum production line.

FAQ

• What is the difference between Gypsum and Plaster of Paris?
  • Gypsum is the natural mineral rock (calcium sulfate dihydrate). Plaster of Paris is the powder produced after gypsum has been heated (calcined) to remove most of its water. It is chemically known as calcium sulfate hemihydrate.
• How is gypsum board made?
  • Gypsum board (drywall) is made by mixing Plaster of Paris with water and other additives to create a slurry. This slurry is then poured and spread between two large sheets of paper. As it moves along a conveyor belt, it hardens, and is then cut to length and dried in large kilns.
• What is the cost of a gypsum production line?
  • The gypsum production line cost varies greatly depending on the capacity (tons per hour), the type of raw material (natural or FGD), and the level of automation. A small line might cost a few hundred thousand dollars, while a large-scale plant can cost several million. We provide custom quotes based on your specific requirements.
• Is gypsum mining harmful to the environment?
  • Like any mining, it has an environmental impact. However, gypsum quarries are often shallow. Modern mining practices include plans for land reclamation, where the land is restored after mining is complete. Also, the use of synthetic FGD gypsum reduces the need for new mining.