JPH03252310A - Method for purifying natural zeolite - Google Patents

Abstract

PURPOSE:To obtain high purity zeolite by avoiding mechanical pulverization of zeolite crude ore grains as much as possible and collapsing swelling clay mineral in ore with swelling action by water when zeolite crude ore is granulated to recover the zeolite. CONSTITUTION:Zeolite-containing tuff containing a swelling clay mineral is broken into pulverized state by mining the tuff and then pulverizing the tuff in such degree not to break zeolite crystal and then dipping the resultant powder in water to swell the above-mentioned swelling clay mineral. Then the pulverized fine powder is classified and only mineral in which crystal grains of zeolite are distributed in the highest density and grain size is in the prescribed range is recovered to provide the high purity zeolite, The swelling clay mineral is preferably montmorillonite and zeolite-containing tuff is preferably clinoptilolite- containing tuff.

Description

[Detailed description of the invention] <Industrial application field> This invention relates to a method for purifying natural zeolite.

<Prior Art> Generally, zeolite is used for water purification, deodorization, gas adsorption, and as a catalyst, but from the viewpoint of cost and mass production, the use of natural zeolite is preferred over artificial zeolite. However, since natural zeolite is a mineral resource, it contains a large amount of impurities and has a low purity, so there is a problem that various expected effects are insufficient.

On the other hand, there are two conventional methods for refining natural zeolite: a dry method and a wet method. (approximately 60-70%), there is not much difference.

In the latter wet method, for example, 1
After being crushed to a particle size of 5xx or less, it is further mechanically wet-pulverized using a ball mill, etc., followed by coarse classification, mechanical re-grinding of downstream waste, centrifugal classification of upstream waste, secondary crushing of coarse particles, and secondary classification. There are known methods such as removing ultrafine particles as impurities, resolidifying them by chemical treatment, and crushing them again to form a powder.

<Problem to be solved by the invention> However, among the above methods, the dry method cannot be expected to produce zeolite with high purity as mentioned above, while the wet method produces raw ore with a purity of 7.
There are reports that zeolite with a purity of 80% or more was obtained with 0% zeolite, but this is an estimate based on a comparison of peak heights by X-ray analysis, and the cation exchange capacity can be measured more accurately. Measurements based on this result in values that are only slightly better or almost the same as those of the raw ore. Moreover, the above method not only goes beyond the scope of extremely limited experimental purification, but also involves many purification steps and is complicated, making it impractical in terms of work efficiency and cost. In particular, it is extremely difficult or impossible to mechanically separate and recover only the zeolite component from a mixture of all the feldspar and other glassy substances contained in the raw ore that have been pulverized and mixed into fine powder.

<Means for solving the problem>Hontemei's method for solving the above problem is to crush zeolite-containing tuff containing swelling clay minerals to an extent that does not destroy the zeolite crystals after mining, and then submerge the zeolite-containing tuff in water. The tuff is pulverized into a fine powder by immersing it in water and swelling the swellable clay mineral, and the crushed tuff is classified to select only those with a particle size within a predetermined range in which zeolite crystal grains are most densely distributed. High-purity zeolite is obtained by recovering the zeolite, and in this method, the mechanical crushing in the pulverizing process of the zeolite ore is kept to the minimum necessary, and in particular, in the final process of pulverizing, the zeolite ore particles are crushed only by the swelling action of montmorillonite. It is characterized by doing the following.

The second feature is that the swelling clay mineral is montmorillonite, and the zeolite-containing tuff is clinoptilolite-containing tuff.

<Function> In the present invention, the ore is crushed by swelling swelling clay minerals such as montmorillonite in the ore with water during immersion, so the zeolite is dispersed in water in its crystalline state and other Since impurities are not subjected to mechanical pulverization, they are divided into those that are dispersed as relatively large particles and those that are dispersed as extremely small particles. As a result, highly pure natural zeolite can be obtained by classifying and collecting the particle size range in which zeolite crystal grains are most densely distributed, which is between extremely small particles and relatively large particles.

<Example> Hereinafter, an example of the present invention will be described in detail. In this example, zeolite raw ore from Shimane Prefecture is used, the clinoptilolite content is about 60% to 70%, and the weight ratio of montmorillonite is about 1
The one containing around 0% was used.

After mining the zeolite raw ore, it is dried to a moisture content of about 3% and crushed to a particle size of 5xm or less using a crusher etc.
Particles with a particle size of 11 were classified and collected. However, the particle size classification was determined as the experimental setting conditions, and the treatment itself
It may contain less than m.

Next, in order to avoid mechanical crushing of the ore grains, no balls were mixed into the ball mill, and water was added in an amount of about 5 times the weight of the ore to create an immersed state.
Drive around 0 hours. The ball mill used at this time has a capacity of IQ, but if the capacity of this ball mill is large, the crushed particle size and classified particle size of the raw ore need not be 5 mm or less.

By the above treatment, the montmorillonite contained in the zeolite ore (#graystone) swells with a large amount of water, and disintegrates into fine powder including coarse particles. Incidentally, montmorillonite is clayey and is known to swell to 7 to IO times its volume in water, and electron microscopy shows that montmorillonite is extremely widely and evenly distributed in clinoptilolite-containing tuff. Furthermore, many clinoptilolite crystals were observed in which plate-shaped crystals of about 5 to 10 μl square formed groups. Judging from the properties of the clinoptilolite crystals, it was estimated that the amount of clinoptilolite dispersed in water was approximately 5 to several tens of μl.

In this example, based on the above consideration, from the fine powder dispersed in water, particles with a particle size exceeding 74 μm are removed using a sieve in accordance with the above estimated range, and fine particles smaller than 5 μ1 are separated and removed using a centrifuge. Classified.

As a result, it was possible to obtain zeolite with a zeolite content of 92% and a high purity that could not be obtained from conventional natural zeolite. This purity measurement is based on cation exchange capacity (CEC).
value).

<Effects of the Invention> The method of the present invention is configured as follows. When pulverizing zeolite raw ore and recovering zeolite, mechanical crushing of zeolite ore grains is avoided as much as possible, and montmorillonite in the ore is disintegrated by the swelling action of water. As a result, zeolite maintains a unique crystalline state within a limited particle size range, and on the other hand, impurities such as feldspar are not subject to mechanical micro-destruction.As a result, the particle size distribution of the two is different, and the zeolite is concentratedly distributed. By classifying and collecting only the particle size range, extremely high purity zeolite can be obtained. Further, according to this method, even if the zeolite content of the raw ore is low, although it requires a long processing time, it has the advantage of being able to obtain relatively stable and highly pure natural zeolite.

Claims (1)

[Claims] 1) Zeolite-containing tuff containing swelling clay minerals,
After mining, the tuff is crushed to the extent that it does not destroy the zeolite crystals, and then immersed in water to swell the swelling clay mineral to crush the tuff into a fine powder.The crushed fine powder is then classified to form zeolite crystal grains. A method for purifying natural zeolite to obtain high-purity zeolite by collecting only those particles with particle sizes within a predetermined range that are most densely distributed. 2) The method for refining natural zeolite according to claim 1, wherein the swelling clay mineral is montmorinonite and the zeolite-containing tuff is clinoptilolite-containing tuff.