Diatomite filter aid mainly intercepts the solid impurity particles suspended in the liquid on the surface and channel of the medium through the following three functions, so as to achieve the purpose of solid-liquid separation:

1、 Screening is a kind of surface filtration. When the fluid flows through diatomite, the pore of diatomite is smaller than the particle size of impurity particles, so that the impurity particles cannot pass through and be intercepted. This effect is called screening. In fact, the surface of the filter cake can be regarded as a screen surface with equivalent average pore size. When the diameter of solid particles is not less than (or slightly less than the pore diameter of diatomite, the solid particles will be "screened" out of the suspension and play the role of surface filtration.

2、 Depth effect depth effect is the retention effect of deep filtration. During deep filtration, the separation process only occurs in the "interior" of the medium. Some small impurity particles passing through the surface of the filter cake are blocked by the tortuous microporous channels in the diatomite and the finer pores in the filter cake. This kind of particles are often smaller than the micropores in the diatomite. When the particles hit the wall of the channel, it may be separated from the liquid flow, but can it achieve this, It depends on the balance of inertial force and resistance of particles. This interception and screening action are similar in nature. They all belong to mechanical action. The ability to filter solid particles is basically only related to the relative size and shape of solid particles and pores.

3、 Adsorption adsorption is quite different from the above two overoxidation mechanisms. In fact, this effect can also be regarded as electrokinetic attraction, which mainly depends on the surface properties of solid particles and diatomite itself. When the particles with small pores in the diatomite collide with the internal surface of the porous diatomite, they are attracted by opposite charges. The other is that the particles attract each other to form chains and adhere to the diatomite. These belong to adsorption. The adsorption is more complex than the first two. It is considered that the solid particles with small pore diameter are intercepted, Mainly due to: (1) intermolecular force (also known as van der Waals attraction), including permanent dipole action

Induced dipole action and instantaneous dipole action 氵 (2) the existence of zeta potential; (3) Ion exchange process

From the above three functions, in the process of net pressure overflow of the suspension, the loose granular diatomite filter aid is used as the filter medium, mainly to provide as many pores as possible for the filter medium layer, that is, the cake, and the formed pore spacing layer, so that the suspension can pass through the small holes of the barrier layer and intercept the solid impurity particles suspended in the liquid on the surface of the medium and between the channels

So as to achieve the purpose of solid-liquid separation.

The invention relates to a new method suitable for refining various grade diatomites into high-grade products step by step through water washing and pickling, which is especially suitable for the separation and refining of medium and low-grade diatomites with high impurities such as clay. It is characterized in that the reducing dispersant oxalate or phosphate is added and dispersed with strong stirring or hot cooking or ultrasonic coupling, so that the diatom body is completely separated from the clay after fully dispersed, Then, the clay and other impurities are effectively separated and removed by high water level sedimentation, and then the sulfuric acid is used for hair washing to convert the clay, iron aluminum oxide and other impurities not removed by water washing method into soluble substances for separation and removal. Finally, the SiO2 ≥ 90%, A1203 ≤ 3.5% and Fe203 ≤ 0.5% of the products can be used to produce high value-added products such as catalyst carrier.

The invention relates to a regeneration method of diatomite filter aid, which takes the waste residue of industrial diatomite filter aid as raw material and is burned at high temperature to remove its organic impurities, restore and improve the original physical and chemical properties, and achieve the purpose of sterilization. The regenerated filter aid can be reused for filtration, and can be widely used in the filtration of industrial liquids in food, pharmaceutical, beer, petrochemical and other industries. The invention has

It has the advantages of reducing environmental pollution, saving resources, easy production and low cost.