End User Focus: Diatomite’s clean fight

By Jessica Roberts, Alex Feytis
Published: Monday, 21 February 2011

The muscle of the filtration world, diatomite, looks to maintain its leading market share as new applications in fuel and water filtration emerge


Kieselgur diatomite from Thiele-Granit’s operation
in the Chad Basin, North Africa.
Dorfner Anzaplan


Diatomite, garnet, perlite, zeolites and sand are the key industrial minerals that serve a range of diverse filtration systems. From beer filtration to swimming pools, to separating oils and metals, each mineral filter aid performs a crucial role in its own dynamic market.

As a broad definition, diatomite and perlite tend to be used in fine filtration for physical entrapment (blocking) of solids, while zeolites act as a chemical filter through absorption. Garnet, meanwhile, has a high specific gravity and thus its primary use is to weigh down other filtration media - although finer grades are also useful filter aids.

Diatomite is by far the most widely used filtration mineral, accounting for around 65% of the market (see p.65). It is a sedimentary mineral that consists of the remains of microscopic floating algae - diatoms Ð that, when alive, remove dissolved silica from water and precipitate it as cell walls.

The mineral’s particle shape and high pore volume give good strength and natural filtering and absorption attributes. Diatomite can be further subdivided into marine and freshwater for greater scope of filtering attributes.

The might of diatomite

“Diatomite is used in many food and beverage filtration applications around world. It’s also used in numerous chemical filtration processes,” Gregg Jones, vice president of global sales and marketing at EP Minerals LLC, told IM.

“As GDP grows around the world, diatomaceous earth (DE) demand will closely mirror this growth rate. Growth in the global need for clean water and alternative fuels is also helping to drive demand growth for DE,” Jones explained.

A leading producer of diatomite and perlite, USA-based EP Minerals began operations in Nevada in 1945. It is a subsidiary of EP Management Corp. and was spun off from EaglePicher Management Co. in 2005.

“We experienced a drop in demand in late 2008 and into 2009 as did most industries. Demand recovered slowly through 2010 and we expect to be above 2008 levels again in 2011,” Jones revealed.

The diatomite capacity picture over the last few years has been relatively constant with no major additions or eliminations. World diatomite production totalled 1.83m. tpa in 2010, led by the USA, China and Denmark, according to statistics from the US Geological Survey.

“The filtration market is quite busy at present and has been for the last 15 months,” a French diatomite producer told IM. “Although demand reduced during the recession, since then it has been very positive. We have returned to the levels seen before the recession.”

Substitutes

The rapid recovery of the diatomite market is an indicator of its importance in the filtration sector. Although a number of minerals and synthetic materials can be substituted for diatomite, its unique properties mean it is preferred in many applications.

In filtration certain grades of garnet, expanded perlite, silica sand and zeolites compete for a share of the fine filtration market. Synthetic filters, notably ceramic, polymeric, or carbon membrane filters and filters made with cellulose fibres, are also trying to break into the industry.

“Many companies have experimented with synthetic filter technology over the last decade,” EP Minerals’ Jones commented. “It’s really a matter of economics and, at the end of the analysis, DE is still the most flexible and economic solution available for solid liquid separation.”

“If people invest in synthetic filter technology, the decision is typically driven by incentives and performance guarantees from the filter manufacturers,” Jones told IM.

Other diatomite producers agree. A leading UK company commented: “Consumers are finding that the economics of synthetic filters are not as good as originally thought.”

“The diatomite market has lost a small amount of market share to synthetic products, but not a huge amount. A lot of the synthetic filter aids have not been successful from a cost point of view,” the company added.

Market focus

To stay ahead of the curve, diatomite producers have focused on research and development into new applications for filter aids - including fuels.

“Product development resources are focused on developing new filtration applications in energy (biofuels filtration, and fossil fuels exploration and production) and in developing clean water solutions - including industrial wastewater, recreational water, and potable water,” Jones commented.

Aside from this, consumers of diatomite have partnered with producers to find new ways of recycling spent filter cake in a move to reduce landfill.

“Today many of our food and beverage filtration customers use spent cake for animal feed and agricultural applications,” EP revealed.

“We are working with our customers to develop cost effective solutions for spent cake re-use and we are dedicating significant resources to this initiative,” said Jones.

The outlook is positive for diatomite but remaining competitive is a concern for producers. As one source explained, prices for diatomite are largely determined by utilities and transport costs - and the general trend within the market is that prices are only heading in one direction.

“We implemented a 5% price increase in the market this year,” Jones told IM. “ In general pricing in the market is up 3-5% in 2011.”


Diatomite at a glance

Diatomite is a chemically inert sedimentary mineral that consists of the remains of microscopic floating algae, ranging in size from 50 to 100µm. When alive, diatoms remove dissolved silica from water and precipitate it as their cell walls. The majority of diatomite is amorphous silica, with a small percentage of crystalline silica which increases when the mineral is calcined.

The intricate structure of diatoms and their complex primary and secondary porosity gives diatomite a very low bulk density combined with excellent capabilities as a filter aid, absorbent, filler, carrier and abrasive - with filtration being its primary market.

Three principal grades of diatomite exist. These include: natural, calcined and flux calcined. Other names for diatomite - such as diatomaceous earth and kieselguhr - often refer to grades of less pure material which may contain significant amounts of clay or other minerals.

Diatomite can contain up to 60% moisture, hence it is important that the product is dried on-site at the mine - otherwise transportation costs are high.


Global diatomite production (1.83m. tpa)



Source: US Geological Survey, 2010


US diatomite markets



Source: US Geological Survey, 2010


Minerals used in filtration



Source: CECA


Diatomite and perlite filtration markets



Beverages:
beer, wine, spirits, and non-alcoholic beverages
Food: sweeteners, edible oils, various additives and components
Chemicals: both organic and inorganic

Source: World Minerals Inc.