Limestone is a carbonate sedimentary rock made up of skeletal fragments from marine organisms. There are many types of liming materials, including calcium carbonate, calcium oxide (also known as “burnt lime” or “quick lime”), calcium hydroxide, magnesium carbonate, and magnesium oxide, to name a few. These are essential minerals utilized in many different industries.
Uses of limestone include:
It is interesting to note that even the Pyramids in Egypt are made of limestone.
At 230 million metric tonnes (mmt), China produces more than 50% of the world’s lime and limestone. Following is the USA at 19 mmt, and India at 16 mmt. USA limestone production is valved at $2.3 billion USD.
Vortex Global designs and manufactures slide gates, diverter valves and loading solutions specifically intended and modified to handle liming materials.
Following is three such examples.
Portland cement is produced by burning a mixture of lime and clay, as well as a few other ingredients, to form clinker. The clinker is cooled then pulverized into fine cement.
Customer: Cement manufacturer
Application: Using a belt conveyor, transport limestone rock from a nearby mine into two crushers.
The customer previously used a bucket-style diverter in this application. The bucket diverter lacked capabilities in that:
The existing bucket-style diverter was replaced with a Vortex Gravity Vee Diverter. The Vortex Gravity Vee Diverter is made up of two independently actuated slide gates, arranged in a “V” configuration. Its primary benefit is that material flow can be directed:
For this application, the Gravity Vee Diverter was modified with:
It takes approximately 1.8 tons of limestone to produce 1 ton of quick lime. Quick lime is produced by heating limestone in a kiln. The process, known as calcining, heats the limestone above 1,500° F | 815° C to liberate a carbon dioxide molecule.
Quick lime has many uses. Primary uses include:
Because quick lime reacts with water to produce heat, it can also be used for food warming in self-heating cans, as well as water heating without open flames.
Customer: Quick lime manufacturer
Application: Control the flow of quick lime from a holding bin.
Even though the quick lime was downstream form the hot kiln, it still contained elevated temperatures of 850 – 1,000° F | 455 – 540° C.
At these temperatures:
For this application, the Vortex Titan Slide Gate was modified with:
The request for pneumatic actuation proved to be more of a challenge. For many higher temperature applications, this temperature constraint typically excludes the use of pneumatic actuators.
An air cylinder must be constructed with rubber seals to effectively contain the air pressures required to move the cylinder rod and actuate the gate. High temperature Viton seals are only rated to 400° F | 205° C. Because Vortex Global also designs and manufactures its own air cylinders, they considered this application and developed a “cylinder within a cylinder” actuator.
It works by:
To date, this solution has met the customer’s requirements and has been successful in the application.
Pebble lime is crushed quick lime, sized between ¼ – 2 ½ in | 6 – 65 mm. It is essential to the following stages in the steelmaking process:
In essence, the steel industry would not exist without pebble lime.
Customer: Steel mill
Application: Pneumatically convey ½ in | 13 mm pebble lime at 10 psig | 0.7 barg from one source toward three destinations.
Challenge: The Customer sought independent control over all three destinations. This would allow pebble lime to be conveyed toward each destination individually, or all closed for a complete shut-off of material flow through the diverter.
For this application, a Vortex Mainline Diverter was designed with three Vortex Titan Pressure Valves (TPVs). The diverter was modified to the following:
As a standard, the Vortex Titan Pressure Valve is also designed with a blade and metal seats constructed from 440 C stainless steel (60 C Rockwell hardness), to address the abrasiveness of handled materials.
Four years after this diverter began operations, the customer ordered a replacement inlet weldment to the same specifications – schedule 80 pipe with ceramic backing. They were very pleased by the extended service life the previous inlet weldment provided. To date, no maintenance has been performed on the Titan Pressure Valves.
Whether it is a product derived from limestone or another mineral, Vortex Global is known for their solutions which are engineered for success in the specific applications they are being sourced for.