You can’t spell Diatomaceous Earth
(And Neither Can We)
“Just use DE”.
That phrase (which you’ve likely heard so many times and probably nodded your head along all the while thinking “I should really know what this is, but I haven’t had time to do the research”), is all too common and more meaningful that you might realize.Without assuming any knowledge of “DE”, let’s break this down and lookat how DE might be good for you!
Diatomaceous Earth, a mouthful by any standard, is an incredibly well-established mineral technology used in more applications than we can easily list here.For companies that have been working with filtration for many years, it’s easy for them to say “just use DE”, but if you are developing new products then you probably want to know where to start.
So, what is DE?
Diatomaceous Earth is a form of silica that is composed of the skeletons of microscopic plants deposited onthe bottom of oceans and lakes.The ore is a soft, friable, amorphous, siliceous mineral.
Ok, so what does that mean?
DE is a naturally occurring, inert mineral that typically has no interaction with the materials flowing through it.This means it is plentiful in supply, can be used in a variety of applications (including food and beverage where it is very common), and, when used correctly, has little to no health or safety concerns for the human body.DE is incredibly sustainable material, due to its constant regeneration and its positive effect on our environment through the removal of carbon dioxide.
Think of it as sand, but with more physical characteristics that assist in mechanical filtration.Essentially, DE exists in different particle sizes andwith different porosity (number and size of microscopic holes).
And what do these fancy holes accomplish?
DE works very much like a food strainer.Let’s say you want to strain the water from your pasta noodles –you can use a strainer with somewhat large holes.However, if you want to separate the seeds from a raspberry, you’d need a strainer with much smaller holes so that everything doesn’t just flow through.And that is an extremely easy way to understand how DE can work in your application –what youare trying to separate and how much you want separated can be adjusted based on the porosity of the DE mineral selection.
Technically speaking, the porous structure of these minerals “catch” the solid particulates.The symmetrical forms of the diatoms resemble a honeycomb structure.Over time, the DE needs to be changed because it will reach a saturation point.If there are a lot of solids in your solution, then the DE would need to be replaced more frequently than if you are running a final pass where the solids or contaminants are much lower.
So, I’m an expert now, right?
Well yes, basically! And if you want to get really good at this, you’ll need to experiment with a few different grades of DE until you get the clarity, cleanliness, flavor, aroma, or color that you desire within your product.
The type of filter equipment that you are using can also influence the product selection. For instance, calcined and flux-calcined DE can be used on most types, whether for filter-press, vertical or horizontal leaf, candle or others.However, if your application primarily uses rotary vacuum drum filters, then the Dicalite flux calcined grades, such as 341, SPEEDPLUS, 375, 2500, 4200, and 5000, are often considered the best in class for performance. This is due to the clarity and filtration rates that can be achieved with these products. The Dicalite SPEEDFLOW is a great, all-purpose calcined product for fine filtering such as in wine, beer or pharmaceuticals. The table below allows for easy comparisons between the grades:
Filter aids are classified by permeability, which is normally expressed in Darcies. A Darcy is defined as the property of porous material which will allow a flow rate of 1ml of water under standard conditions through 1cm2 of area under one atmosphere of pressure. This chart expresses the relationship between each grade and how the permeability effects qualities such as the sparkle (level of carbonation) or clarity:
A lower permeability means that the “holes” are smaller, such as in the food strainer example above. Products such as Dicalite 215 would allow the least amount of particulate to flow through, and Dicalite 7000 would allow the most particulate to flow through.
Lastly, there are a few instances where DE is not the best fit, such as filtration slurries with a high alkalinity (>12 pH) or applications requiring recover of the solids removed in the filtration process. In those instances, Ravago Chemicals North America (RCNA) can help you choose alternatives to best meet your needs.
Ok, I’m ready to try some, what next?
Dicalite Management Group offers over a dozen different grades of Diatomaceous Earth filter aids to meet any industrial filter media process. Selection of the proper grade is critically important to ensure design, flow rate, clarity, and to maximize performance and minimize total filtration costs.
Luckily, RCNA can help you get started by providing some focused data for common industries. Check out the full line of filtering materials here. Can’t find what you are looking for? Don’t hesitate to contact us for more information or use our forum to start a discussion with our suppliers or others in your industry.
Some examples of how DE can be used:
- Filtration – the small particle size and high porosity make DE excellent for solids separation processes
- Fillers – in applications like cement, plastics, rubber, asphalt shingles and paints, DE can be added to reduce weight, improve whiteness or reduce stickiness
- Absorbents – from liquid spills to kitty litter, DE can be excellent for cleanup and removal applications
- Abrasive and polishing – DE particles have a high surface area and can be commonly found in metal cleaners, face scrubs, toothpaste, and other cosmetic applications