Gypsum is a naturally occurring hydrated salt compound of soft calcium sulfate, and its use depends on the industry in which it is used. It was formed millions of years ago as prehistoric sea beds evaporated, and can be found in large, thick beds or smaller, thinner ones. Today, gypsum is typically mined in open pit quarries and processed similar to other such operations. Through thermal processing, or pyro processing, it is broken down and refined into more recognizeable forms. It is something that most people probably have not heard of but almost everyone uses, and on a daily basis.
There are endless uses for gypsum. As an ingedient in plaster, it has been used in many things from kindergarten crafts to Michelangelo’s work on the Sistine Chapel ceiling. It is a very versatile medium that is required in many forms, including construction, art and medicine. Molds for a variety of things like pottery and decorative building adornments are similarly composed to that of Plaster of Paris. A common misconception is that writing chalk is made from chalk rock, or calcium carbonate, but it is actually made from gypsum, or calcium sulfate. As an agricultural fertilizer, is it used as a soil additive and conditioner to control moisture content. Gypsum is also widely known as an ingredient in drywall and Portland cement, making it one of the most commonly used construction materials worldwide.
The pharmaceutical industry uses gypsum as a supplement to medications or as a dietary calcium supplement, while surgical splints require gypsum as plaster for mending a broken bone in a cast. To make tofu, a coagulant like gypsum is added to soy milk. In canned vegetables, jams and baked goods, gypsum is a source of added calcium. Gypsum is also added to beer to accentuate the bitterness while modifying the pH levels as a water treatment.
Some common properties of gypsum are that it is white in color, non-abrasive, odorless, tasteles, non-toxic and flame retardant. It is also much softer than similar raw materials, and can be marked with just the pressure of a fingernail.
Gypsum layers
After the mineral has been mined, transported and crushed to the required size, it can be processed. Since gypsum naturally occurs with some percentage of water, the water must be driven off. When gypsum is heated to about 250 degrees Fahrenheit (120 degrees C) for about an hour, the result is a hemihydrate or Plaster of Paris material. Changing the temperature, reducing the chemical water content or individual size of the processed product will affect which industries or products it can be used it.
There are many ways to dry the gypsum, mainly depending on the scale of how much is being processed and whether it will be mechanical or manual labor. This is where thermal processing equipment like a fluid bed dryer comes in. As the still-hydrated gypsum is fed into a dryer, it fluidizes the bed of material with a flow of heated air or gas that is strong enough to lift the material up so it behaves like a fluid and is evenly dried. The heated air is then recycled to dry the material over and over in a closed loop air system. Once the desired amount of dryness is achieved, the material can pass through a cooling zone where cooler air reduces the temperature of the product to the desired level. For more information about the operation of a fluid bed dryer, please refer to our previous article, How a Fluid Bed Dryer Operates.
Another option for gypsum drying is a rotary calciner. In a calciner, material passes indirectly through a furnace via a rotating drum tube. Since the calciner is slightly inclined, the material is directed through the cylinder by gravity as it rotates. It is an automatic and continuous process that can be heated by electricity or gas. It has the added feature that gases and solids can move in the same direction or opposite directions. At the end of the calciner, the material exits the machine and waste gases can be ventilated or even recycled back to the calciner.
After processing, a widely usable and versatile gypsum product remains. Regardless of a customer's needs, from the standard to the highly specialized, Heyl & Patterson can ensure that the right equipment gives them the right product for their needs. Applications for both fluid bed dryers and rotary calciners can be tested at Heyl & Patterson's pilot plant lab facility.
To learn more about rotary calciners engineered by Heyl & Patterson, click here.
Thermal Processing Equipment Benefits a Gypsum Operation
Gypsum is a naturally occurring hydrated salt compound of soft calcium sulfate, and its use depends on the industry in which it is used. It was formed millions of years ago as prehistoric sea beds evaporated, and can be found in large, thick beds or smaller, thinner ones. Today, gypsum is typically mined in open pit quarries and processed similar to other such operations. Through thermal processing, or pyro processing, it is broken down and refined into more recognizeable forms. It is something that most people probably have not heard of but almost everyone uses, and on a daily basis.
There are endless uses for gypsum. As an ingedient in plaster, it has been used in many things from kindergarten crafts to Michelangelo’s work on the Sistine Chapel ceiling. It is a very versatile medium that is required in many forms, including construction, art and medicine. Molds for a variety of things like pottery and decorative building adornments are similarly composed to that of Plaster of Paris. A common misconception is that writing chalk is made from chalk rock, or calcium carbonate, but it is actually made from gypsum, or calcium sulfate. As an agricultural fertilizer, is it used as a soil additive and conditioner to control moisture content. Gypsum is also widely known as an ingredient in drywall and Portland cement, making it one of the most commonly used construction materials worldwide.
The pharmaceutical industry uses gypsum as a supplement to medications or as a dietary calcium supplement, while surgical splints require gypsum as plaster for mending a broken bone in a cast. To make tofu, a coagulant like gypsum is added to soy milk. In canned vegetables, jams and baked goods, gypsum is a source of added calcium. Gypsum is also added to beer to accentuate the bitterness while modifying the pH levels as a water treatment.
Some common properties of gypsum are that it is white in color, non-abrasive, odorless, tasteles, non-toxic and flame retardant. It is also much softer than similar raw materials, and can be marked with just the pressure of a fingernail.
Gypsum layers
After the mineral has been mined, transported and crushed to the required size, it can be processed. Since gypsum naturally occurs with some percentage of water, the water must be driven off. When gypsum is heated to about 250 degrees Fahrenheit (120 degrees C) for about an hour, the result is a hemihydrate or Plaster of Paris material. Changing the temperature, reducing the chemical water content or individual size of the processed product will affect which industries or products it can be used it.
There are many ways to dry the gypsum, mainly depending on the scale of how much is being processed and whether it will be mechanical or manual labor. This is where thermal processing equipment like a fluid bed dryer comes in. As the still-hydrated gypsum is fed into a dryer, it fluidizes the bed of material with a flow of heated air or gas that is strong enough to lift the material up so it behaves like a fluid and is evenly dried. The heated air is then recycled to dry the material over and over in a closed loop air system. Once the desired amount of dryness is achieved, the material can pass through a cooling zone where cooler air reduces the temperature of the product to the desired level. For more information about the operation of a fluid bed dryer, please refer to our previous article, How a Fluid Bed Dryer Operates.
Another option for gypsum drying is a rotary calciner. In a calciner, material passes indirectly through a furnace via a rotating drum tube. Since the calciner is slightly inclined, the material is directed through the cylinder by gravity as it rotates. It is an automatic and continuous process that can be heated by electricity or gas. It has the added feature that gases and solids can move in the same direction or opposite directions. At the end of the calciner, the material exits the machine and waste gases can be ventilated or even recycled back to the calciner.
After processing, a widely usable and versatile gypsum product remains. Regardless of a customer's needs, from the standard to the highly specialized, Heyl & Patterson can ensure that the right equipment gives them the right product for their needs. Applications for both fluid bed dryers and rotary calciners can be tested at Heyl & Patterson's pilot plant lab facility.
To learn more about rotary calciners engineered by Heyl & Patterson, click here.
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