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Diatomaceous earth or diatomite powder is a natural soft sedimentary rock that is composed of the fossilized skeletal remains of diatoms (hard shelled algae). This unique material has been used widely in filtration, absorbent applications, fillers and insulation products. But not all diatomite powder has equivalent performance. Quality can vary significantly depending on the source deposit, processing treatments and final treatment. Hebei Hezhen Industrial Co., Ltd. engages in mining, processing and marketing of the non-metallic minerals as diatomite series products. Understanding quality will help buyer to purchase efficiently.
Purity and Silicon Dioxide Content
The purity of the silicon dioxide (SiO₂) content is the most basic parameter of the quality of diatomite powder. Good-grade diatomite has 85% or more SiO₂ with the rest being other minerals i.e., clay, quartz, feldspar and metal oxides. At lower purity grades, these contaminants are high and this lowers the performance in most of the application. In filtration, the impurities may be washed into the filtrate or prematurely clog the filter beds. For absorbent applications, impurities dilute the absorption capacity. For filler applications, impurities may affect color or chemical reactivity. Hebei Hezhen Industrial Co., Ltd. obtains diatomite deposits with high content of SiO₂ and low contaminations. We also use our processing steps to eliminate undesirable minerals in order to obtain the purity levels needed in demanding uses.
Diatom Frustule Structure and Porosity
It is not only the chemical composition of diatomite that renders the powder unique: the three dimensional structure of the diatom frustules is also complex. The silica shells created by diatoms have intricate pore structures and large internal surface area. These frustules can be retained in the processing, and the resultant powder has a very high porosity, usually more than 80 percent by volume. This porosity directly defines performance in filtration, absorption and thermal insulation applications. Poorly processed diatomite can contain broken or pressed frustules with less pore volume. Excessive grinding can break the fragile structures into small pieces which do not have the same functional characteristics. Hebei Hezhen Industrial Co., Ltd. accomplishes this through modern advanced production technology that retains the integrity of the diatom frustule, yet manages to attain the required particle size.
Particle Size Distribution and Consistency
Fine particles give excellent clarification and slower flow whereas coarser particles give faster flow but may let smaller contaminants pass through. Particle size affects the rate of uptake of liquid and the ultimate holding capacity, in the case of absorbent applications. In filler applications, a uniform dispersion and predictable end-product properties require the consistent particle size. Diatomite powder of high quality has a compact particle size distribution with no excessive or small particles. The concept of batch-to-batch consistency is also of high significance to industrial users who are not able to adapt formulations to each shipment. Hebei Hezhen Industrial Co., Ltd. has a rigid management on particle size by use of fine classification machinery and in-process inspection. The fact that we are ISO9001:2000 certified in international quality systems shows that we take quality as a consistent factor.
Color and Brightness Specifications
Diatomite in its pure form is white to off-white. Typical pollutants that result into gray, yellow, pink, or brown discoloration are iron oxide and organic matter. In the case of paint, plastic, and coating fillers, whiteness has a direct impact on the brightness of the final product and the quantity of titanium dioxide or other pigments needed. Even in filtration systems where color does not matter so much, diatomite with high color can be a pointer of high levels of impurities that influence other performance characteristics. Hebei Hezhen Industrial Co., Ltd. optimizes diatomite to produce a constant brightness level, and the diatomite may be treated with calcareous and other additives to make it whitish when needed.
Calcination and Surface Treatment Effects
Raw diatomite powder may be further refined or treated by calcination or surface treatment to achieve particular properties. Most filtration applications prefer using calcined diatomite due to its higher flow rates and consistency of performance. Even coarser and more permeable products are obtained by means of flux-calcined diatomite which is treated in the course of the calcination process with a fluxing agent. But calcination does decrease surface area as well as altering the amorphous silica structure. Non-calcined natural diatomite is suitable for absorbent and some filler applications. Surface treatments may also be used to enhance compatibility with particular polymer systems or add functionality e.g., hydrophobicity. Hebei Hezhen Industrial Co., Ltd. provides natural and calcined diatomite grades, and flux-calcined grades are available to meet special filtration requirements.
Different factors such as purity, frustule structure, particle size distribution, color, treatment during calcification, and moisture content determine the quality of the diatomite powder. Knowledge of such parameters allows buyers to pick the correct grade to apply in their specific use and to be able to assess suppliers. Hebei Hezhen Industrial Co., Ltd. is friendly to domestic and foreign merchants to trade with our company, cooperate in good faith and to pursue mutual growth.
