JPH0674144B2 - Purification method of natural zeolite - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for purifying natural zeolite.

<Prior Art> In general, zeolite is used as a catalyst in addition to a water purifying action, a deodorizing action, a gas adsorbing action, but from the viewpoint of cost and mass productivity, it is desired to use a natural zeolite rather than an artificial zeolite. However, since natural zeolite is a mineral resource and contains a large amount of impurities, and its purity is low, various expected actions are insufficient.

On the other hand, conventional natural zeolites are refined by a dry method and a wet method.The former is to pulverize and classify after mining to remove a part of impurities such as quartz having high hardness. (Approximately 60-70%) is not much different.

In the latter wet method, after mining, for example,
What was pulverized to a particle size of mm or less is further mechanically wet pulverized using a ball mill or the like, and coarse classification, mechanical re-pulverization of downstream discharge, upstream exhaust centrifugal classification, secondary pulverization of coarse particles, secondary classification It is known that ultrafine particles are removed as impurities, a chemical treatment is performed to re-solidify, and the mixture is re-crushed to form a powder.

<Problems to be Solved by the Invention> However, in the above method, a high purity zeolite cannot be expected in the dry method as described above.
%, A zeolite with a purity of 80% or more was reported, but this is an estimated value by comparing the peak heights by X-ray analysis, and the cation exchange capacity that allows more accurate measurement Based on the measurement, the value obtained is slightly better or almost unchanged from that of the raw ore. Moreover, the above-mentioned method not only puts out a very limited range of experimental purification,
It has many purification steps and is complicated, and it is not practical 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 pulverized feldspar or other glassy substance contained in the raw ore that is pulverized and mixed into a fine powder.

<Means for Solving the Problems> The method of the present invention for solving the above-mentioned problems is that zeolite-containing tuff containing a swelling clay mineral is ground in water after being crushed to the extent that zeolite crystals are not destroyed after mining. Immersion, swelling the swelling clay mineral to disintegrate the tuff into a fine powder state, classify the pulverized fine powder, and recover only those with a grain size within a predetermined range in which zeolite crystal grains are most densely distributed. In this method, the mechanical crushing in the crushing process of the zeolite ore is kept to the minimum necessary, and especially in the final process of crushing, the zeolite ore grains are crushed only by the swelling action of montmorillonite. It is characterized by that.

The second characteristic is that the swelling clay mineral is montmorillonite and the zeolite tuff is clinoptilolite tuff.

<Operation> In the present invention, since the ore is disintegrated by swelling the swelling clay mineral such as montmorillonite in the ore with the water at the time of immersion, the zeolite is dispersed in water in its crystalline state and Since other impurities do not undergo mechanical fine crushing, they are divided into those which are dispersed with a relatively large particle size and those which are dispersed as extremely small particles. As a result, high-purity natural zeolite can be obtained by classifying and recovering the particle size range in which the zeolite crystal particles are most densely distributed and located between the ultrafine particles and the relatively fine particles.

<Examples> In the following, examples of the present invention will be described in detail. In this example, a zeolite ore from Shimane Prefecture is used, and the clinoptilolite content is about 60% to 70%, and the montmorillonite is about 10% by weight. I used the one included around%.

After mining the zeolite ore, it was dried to a water content of about 3%, crushed with a crusher or the like to a particle size of 5 mm or less, and classified to a particle size of 3 to 5 mm. However, the classification of the granulometer is set as a setting condition of the experiment, and the treatment itself may include 3 mm or less. Next, do not mix balls in the ball mill to avoid mechanical crushing of ore grains, and add water in a weight ratio of about 5 times the amount of ore to make it immersed.
The ball mill is driven for about 20 hours. The ball mill used at this time has a capacity of 1. However, when the capacity of the ball mill is large, it is not necessary that the crushed particle size or classified particle size of the raw ore be 5 mm or less.

By the above treatment, the zeolite ore (tuff) contains montmorillonite containing a large amount of water and swells, and is disintegrated into a fine powder containing coarse particles. By the way, it is known that montmorillonite is clay-like and swells to 7 to 10 times its volume by water, and that montmorillonite is extremely widely and uniformly distributed in clinoptilolite-bearing tuff. In addition, many clinoptilolite crystals were observed in which plate-like crystals of about 5 to 10 μm square formed a group. Considering the properties of the clinoptilolite crystals, it was estimated that the clinoptilolite dispersed in water was concentrated in the range of approximately 5 to several tens of μm.

In the present embodiment, based on the above idea, fine powder dispersed in water having a particle size of more than 74 μm is removed by sieving according to the above estimated range, and fine particles of less than 5 μm are separated and removed by a centrifuge. did.

As a result, it was possible to obtain a high-purity zeolite with a zeolite content of 92%, which was not possible with conventional natural zeolites. This purity measurement is cation exchange capacity (CEC value)
It was done by.

<Effect of the Invention> The method of the present invention is configured as follows, and when the zeolite ore is pulverized to recover the zeolite, mechanical crushing of the zeolite ore grains is avoided as much as possible, and the montmorillonite in the ore is disintegrated by the swelling action of water. In order to do so, the zeolite maintains a unique crystalline state in a limited particle size range, while impurities such as feldspar are not subject to mechanical microdestruction, and as a result, the particle size distributions of the two are different and the above zeolites are concentrated. By classifying and recovering only the particle size range, extremely high-purity zeolite can be obtained. Further, according to this method, although the processing time is long even if the content of zeolite in the raw ore is small, there is an advantage that natural zeolite of high purity can be obtained relatively stably.

Claims (2)

[Claims] 1. A zeolitic tuff containing a swelling clay mineral is crushed after mining to the extent that zeolite crystals are not destroyed and then immersed in water to swell the swelling clay mineral, whereby the tuff is finely divided. Disintegrate into
A method for purifying natural zeolite, in which high-purity zeolite is obtained by classifying fine powder that has been disintegrated and recovering only those having a grain size within a predetermined range in which zeolite crystal grains are distributed in the highest density. 2. The method for purifying natural zeolite according to claim 1, wherein the swelling clay mineral is montmorillonite and the zeolite tuff is clinoptilolite tuff.