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Benefits of Vacuum-Assisted Filtration in Creating Exceptionally Dry Filter Cakes

Wednesday, October 21, 2020
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Vacuum Assisted Filtration

Micronics has previously blogged on the benefits of vacuum-assisted Filtration and, in particular, the benefits of Micronics “VP” Vacuum Filter Presses, one of the press products in Micronics’ extensive portfolio of filter press models and technologies. In-situ drying – drying within the Filter Press – has become an increasingly popular and significant trend worthy of consideration because of the value it delivers. In this updated blog post, we would like to discuss vacuum filtration technology and what it can do for your business.

Vacuum Filter PressThe Micronics Vacuum Filter Press starts the filtration process like a traditional Micronics Membrane Filter Press, which already creates a filter cake with a high level of dry solids. As a point of reference, a typical Membrane Filter Press has membrane filter plates that will inflate and squeeze out extra water from the filter cake. The big difference between a typical Membrane Filter Press and a Vacuum Filter Press is in the secondary drying of the filter cake that has been produced.

What Is the Vacuum Filtration Process?

At the heart of the Micronics “VP” Vacuum Filter Presses is a highly engineered and robust control system that incorporates both vacuum and thermal energy to drive the remaining moisture from the filter cake.

By lowering the system pressure, the transition from liquid to vapor occurs at a temperature suitable for the many polymers incorporated into today’s filter presses. With this system, it is possible to remove 95%+ of the moisture from the filter cake at temperatures of 110oF – 120oF.

The vapor, once removed, can be condensed back into a liquid outside of the filter press for reuse or disposal.

This process is not some black magic, but is known science.

Many of you are familiar with the phenomenon in which water will boil at lower temperatures with higher elevations (lower atmospheric pressure). By manipulating the system’s environment, we are capable of producing bone-dry filter cakes more economically than many other technologies.

What Are Some of the Benefits of Boiling Off Residual Moisture at Relatively Low Temperature?

The fact that Micronics’ Vacuum Filter Press boils off water at ~114o F offers clients a number of advantages vs. use of typical dryers. This temperature allows for plastic plates/cloths to be utilized as well as plastic piping in some instances. Micronics’ Vacuum Filter Press offers advantages for applications where the slurry may be acidic and for which conventional dryers would not be suitable as the acid would corrode the metal components or drive the costs much higher based on needing to use special alloys for materials of construction.

Vacuum Assisted Filter Press

95%+ Solids:  Creating Bone-Dry Filter Cakes Using the Micronics “VP” Vacuum Filter Press

To provide the very best heat transfer, Micronics uses high heat transfer (HHT) vacuum membrane filter plates to produce consistently bone-dry filter cakes.  Using the Micronics Vacuum Filter Press, the user can achieve the level of dryness needed without any traditional secondary drying steps.

When Micronics talks about achieving “bone-dry filter cakes” with a heated vacuum-assisted-drying Filter Press, it means our ability to achieve a dramatic 95% dry solids or better.

Why Do We Focus So Extensively On Engineered Filtration Solutions to Create Very Dry Filter Cakes?

We focus on solutions for achieving bone-dry cakes so that you don’t need to worry about excess moisture in your filter cakes or the need for secondary drying of the filter cakes.  Drying in situ – within the filter press – without the need for additional handling, minimizes the extra time, effort, and added costs to move wet cake. It also limits the exposure of your filter cake to operators, crucial in many industrial applications.

Just as a rule of thumb, a “standard” filter press might achieve 40% dry solids. A Membrane Filter Press (utilizing membrane-squeeze) might achieve 50% dry solids. A Micronics “VP” Vacuum Filter Press can achieve a whopping 95% dry solids, all based on drying within the Filter Press itself.

Mining & Mineral Processing: Vacuum-assisted Filtration Can Play A Vital Role

Vacuum-assisted filtration often plays a vital role in processing precious metals such as silver, gold, and platinum. Precious metal concentrates need to be very, very dry before melting in a crucible and pouring bars or ingots. The introduction of water into a molten metal process can have disastrous consequences as the abrupt phase change can cause molten metal to project from the crucible and endanger operators. This is problematic both relative to product yield as well as for safety.  Vacuum Filter Presses such as Micronics offers are an attractive filtration solution for many process engineers and safety directors alike.

Micronics is a leader in Filter Presses for Mining & Mineral Processing and you can trust Micronics’ proven engineered filtration solutions expertise and range in Mineral Concentrates, Mine Tailings, and Merrill-Crowe processes. As we always say, there is no one size fits all filtration solution, and Micronics is very well-positioned to configure the right solution for your operation’s needs.

Drier Cakes Mean Less Money Spent on Hauling and Less Material Going to Landfill

In addition to customers that need dryer filter cakes for secondary post processing, some customers can benefit from the saving on hauling and conserving material going to landfill. The more moisture that you remove during the pressure filtration process, the less industrial waste volume there is to haul to the landfill. That’s more money in your pocket.

Micronics is committed to helping our customers with advanced, cost-effective filtration solutions that help improve operating efficiencies, reduce lifecycle costs, and support the environment.  We can engineer a solution for you to meet both your dewatering and drying needs, including our other specialty vacuum drying equipment such as a heated squeeze skid and vacuum skid.

Taking the worry out of getting consistently dry filter cakes is what Micronics can provide for you.  This can be both a benefit for waste applications as well as applications in which the cake material is the product itself. If you are looking for consistently bone-dry filter cakes with minimized secondary handling or drying, look to Micronics to provide you an engineered filtration solution.

Contact us to learn more about Micronics “VP” Vacuum Pulse Drying Filter Presses as well as our full range of custom and standard filter press designs & options. Our team is eager to discuss your unique filter press applications with you.