KR100388575B1 - A manufacture carefully of phosphoric acid gypsum - Google Patents

Abstract

The present invention relates to a method for refining phosphate gypsum, the industrial process through a simple classification process of refining and extracting only the product forming a particle size range of a certain range by using the rotational force and suction force of the air phosphate gypsum produced as a by-product in the process It is to provide a purification method that can be recycled as a raw material.

Description

Purification method of phosphate gypsum {A MANUFACTURE CAREFULLY OF PHOSPHORIC ACID GYPSUM}

The present invention relates to a method for refining phosphate gypsum, and more particularly, it is possible to recycle after removing harmful impurities such as heavy metals by refining phosphate gypsum, which contains phosphate, among waste gypsum generated in various manufacturing processes using natural gypsum. It relates to a purification method to make.

Gypsum is a common form of calcium sulphate minerals and is often found in very large evaporation deposits, which usually form first and then add water between 0 and 300M below the surface (depending on geological, geological and climatic conditions). As it turns into gypsum.

On the other hand, since there is no natural gypsum in Korea, it is imported from Morocco, Japan, and China, and is used in phosphate fertilizer manufacturing process as a by-product of phosphate gypsum, petrochemical and thermal power plant desulfurization gypsum, lucky and Smelting gypsum, smelting byproducts such as Korea Zinc, and PAC (polyaluminum chloride) gypsum produced in Yeongil Chemical are produced.

Korea's gypsum self-sufficiency is 0%, which depends on total imports. Natural gypsum has been produced domestically in the past but has not been produced since 1985.

However, as the domestic industry is diversified, gypsum demand is steadily increasing, and as imports continue to increase, there is a problem that adversely affects the domestic trade balance.

In addition, the amount of waste gypsum left unused also increases gradually.For example, the amount of waste gypsum generated by Namhae Chemical, which is accumulated in the area near Yeocheon Industrial Complex, is estimated to be about 17 million tons over 10 years, causing environmental pollution. Although it has been pointed out, most of them are left unattended because they have to go through a complicated and expensive purification process to reuse them as industrial raw materials.

In particular, phosphate waste gypsum is estimated at more than 2 million tons per year, and its crystal phase is irregular and contains a large amount of impurities such as phosphate and heavy metals, which are harmful elements, and it is necessary to recycle them. There was a problem that causes environmental pollution.

The present invention has been proposed to solve the above problems with the conventional waste gypsum treatment, by recycling the waste gypsum can be recycled to gypsum obtained by obtaining the extract to maintain the particle size within a certain range through a low-cost purification process The purpose is to provide.

The above object is a method for extracting the purified gypsum product having a particle size within a certain range by inputting gypsum phosphate in a plurality of chambers in communication with each other:

(1) classifying the phosphate gypsum raw material on a predetermined particle size basis using wind power inside the first chamber while the air suction force common to the respective chambers is applied from the outside by the vacuum pump;

(2) introducing the selected gypsum product having a predetermined particle size among the classified gypsum raw materials into the second chamber by using the air suction force;

(3) The fine particles in the gypsum product having a predetermined particle size or less introduced into the second chamber are raised by the air suction force which is continued to be collected to the third chamber side, and the lower part of the second chamber has a predetermined particle size range by its own weight. Having the purified gypsum selected;

(4) extracting the purified gypsum product selected in the second chamber; it can be made through a phosphate purification method comprising a.

1 is an embodiment of an apparatus for carrying out the purification process of the present invention.

2 is a flow chart showing a purification process of the present invention.

Figure 3 is a photograph of the impurity product collected in accordance with the present invention.

Figure 4 is a photograph of the purified gypsum product screened according to the present invention.

Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

First, before looking at the purification method of the present invention, the distribution of particle size of the phosphate waste gypsum to be put into the purification process will be described with reference to the following [Table 1].

Mesh Weigh (g) Wt% +28 7 0.8 -28 / + 35 3 0.3 -35 / + 48 3 0.3 -48 / + 65 43 5.2 -65 / + 100 245 29.8 -100 / + 200 333 40.5 -200 / + 325 104 12.6 -325 83 10.5 Total 821 100

As can be seen from the above, the overall particle size distribution of the phosphate waste gypsum was found to be about 70 Wt% of the total grain size between -65 mesh and +200 mesh, and fine particles (-200 mesh) thinner than 200 mesh were also about 13 Wt%. It can be seen that the distribution. This is because of the characteristics of gypsum product powder, the dehydration and drying process is more advantageous than granule product, and it is easy to separate and select high quality gypsum product from impurities.

In addition, the results of the chemical analysis of the products of the phosphate pyeseokgo phosphorus (P ₂ O ₅₎ was shown to 0.46Wt%, a particle size in the share in the results of analysis of different levels, mainly gypsum product of the coarse particle P ₂ It was confirmed that a relatively large amount of O ₅ remained.

In addition, other heavy metal components (Ba, Co, etc.) were also mainly detected in products of relatively large particle size, Table 2 shows the main mineral chemical composition of these phosphate waste gypsum products.

Fe ₂ O ₃ (Wt%) P ₂ O ₅ (Wt%) Ba (ppm) Co (ppm) Cu (ppm) +28 Mesh 0.13 3.27 48 4.1 16 +65 Mesh 0.10 2.44 47 4.1 15 -65 Mesh 0.072 0.083 34 3.8 9.1

Looking at [Table 2] it can be seen that as the particle size of the particles being selected from the waste gypsum product is smaller, the remaining impurities are reduced.

However, if the particle size standard is set too small, the recycling ratio according to the weight is reduced, so that the product having a particle size range of approximately -65 mesh, that is, a value of less than 65, which can exceed 70 Wt% in the above [Table 1]. It may be desirable to select.

Therefore, in the embodiment of the present invention by using a dry device having a configuration as shown in Figure 1 by extracting the phosphate waste gypsum by particle size, it is possible to select the refined gypsum products minimized impurities contained in the gypsum product.

First, look at the configuration of the dry device as follows.

An air intake cylinder 1 is installed on the first chamber 10, and a guide ben 3 formed of a cylindrical tube is mounted therein, and a supply hopper for supplying a gypsum product to the upper part of the guide ben 3. (2) is installed, the inside of the guide ben (3) is equipped with a rotary fan (5) receiving the rotational force from the drive motor (4), the rotary fan (5) is branched from the center to the radial angle It consists of a cylindrical body with a number of paddles arranged.

And below the rotating fan (5) is connected to the guide tube (7) which is in communication with the lower end of the second chamber 20, the second chamber 20 is another guide tube (8) connected to the upper end It is in communication with the third chamber (30), and the lower end of the third chamber 30 is in communication with the vacuum pump 40 is generated internal suction force is generated.

In the drawings, reference numerals 9 and 19 denote reservoirs under the chambers, respectively, and 31 denote filters for collecting powder particles of the gypsum product.

The gypsum phosphate purification process of the present invention using the apparatus having such a schematic configuration will be described below with reference to the flowchart of FIG. 2.

For reference, the gypsum product used in this embodiment is a raw material provided from Namhae Chemical, and the particle size range of the gypsum product to be refined was set to -65 to +200 mesh.

When the driving motor 4 and the vacuum pump 40 are operated as the power is applied, the high speed rotation of the rotary fan 5 starts to generate a powerful air suction force so that external air can flow through both sides of the air intake cylinder 1. It is sucked inside. (ST 1)

And, the gypsum raw material is injected into the upper portion of the rotary fan 5 by the suction force generated while being displaced to the outside by the outward force by the centrifugal force hitting the collision cylinder (not shown) installed on the inner upper portion of the guideben (3) It is lowered between the gap of the guideben (3) and the rotary fan (5). (ST 2)

At this time, products having a relatively large particle size (+65 mesh) are dropped into the lower first chamber 10 by centrifugal force and gravity to be accumulated in the three-dimensional particle storage tank (9) at the bottom, the products forming a particle size of -65 mesh Since its own weight is relatively light, it is sucked into the rotary fan 5 by suction force and is introduced into the second chamber 20 through the guide tube 7. (ST 3)

In addition, since the continuous air suction force is also acting in the second chamber 20, some of the fine particles (-200 mesh) of the particles introduced through the guide tube 7 are raised again by the air suction force and thus the guide tube ( 8) Products between -65 mesh and +200 mesh flowing into the third chamber 30 and satisfying a predetermined granularity range are lowered by their own weight to be stacked in the reservoir 19 at the bottom of the second chamber 20. You lose. (ST 4)

Thereafter, the fine particles introduced into the third chamber 30 are collected by the filter 31, so that only pure air is exhausted to the outside through the vacuum pump 40 while preventing contamination of the external environment. .

In addition, if the particle size of the selected product does not satisfy the particle size value between -65 mesh and +200 mesh enough to check the gypsum products collected in the reservoir 19 of the second chamber, the purification process is performed once again. do. (ST 5)

In carrying out this process, the most important factor is the setting of the suction power of the air.

Therefore, in the primary, the gypsum product, which is introduced with a weak suction force, is separated, and the purified gypsum is recovered three times while gradually increasing the suction power, thereby making it possible to extract a more uniform gypsum product in a desired particle size range. (ST 6)

On the other hand, Figure 3 is a photograph showing the products accumulated in the reservoir (9) at the bottom of the first chamber in the process, most of the particle size of +65 mesh is large and irregular state of about 7Wt% of the phosphate initially injected It was confirmed that it contains a large amount of impurities such as heavy metals.

The final refined gypsum products accumulated in the reservoir 19 at the bottom of the second chamber are about 70 Wt% and generally in the range of -65 mesh and +200 mesh, which have a uniform particle size as shown in the photograph in FIG. 4. It can be seen.

In the final refined gypsum screened in the reservoir 19 of the second chamber, as shown in [Table 2], not only phosphorus components remaining in the phosphate waste gypsum but also various heavy metal components are greatly reduced, and thus it is known that recycling is possible. Can be.

In addition, the 23Wt% gypsum product is mostly collected in the filter 31 of the third chamber 30 as fine particles of -200 mesh.

Therefore, it can be seen that the final extracted refined gypsum can be recycled into various industrial raw materials such as agricultural, livestock, cement, and building materials through the post-treatment process.

In addition, although specific embodiments of the present invention have been described above, it is apparent that the present invention may be modified in various ways by those skilled in the art.

For example, in the above embodiment, a classification apparatus using a centrifugal force by a rotating fan is used as a means for generating a rotational force of air, but it is also possible to classify the gypsum product by particle size using other methods of wind and suction force.

Accordingly, these various modified embodiments should not be understood individually from the spirit or scope of the present invention, these modified embodiments should fall within the scope of the appended claims of the present invention.

As described above, the phosphate gypsum refining method of the present invention is a simple classification process for refining and extracting only phosphate gypsum produced as a by-product in the phosphate fertilizer manufacturing process using a rotational force and suction force of air to achieve a specific particle size range. Through this, it is possible to recycle as industrial raw materials.

This reduces the amount of waste gypsum that acts as a cause of environmental pollution, and at the same time makes the recycling of gypsum at a low cost, thus showing the advantage of replacing imports of natural gypsum.

Claims (4)

In a method for extracting refined gypsum products having a particle size within a certain range by inputting gypsum phosphate in a plurality of chambers in communication with each other: (1) While the air suction force common to the respective chambers is applied from the outside by the vacuum pump, the phosphate gypsum raw material is classified on the basis of a predetermined particle size by using wind power inside the first chamber, and the impurity more than the predetermined particle size is stored in its own weight. Gathered at the bottom of the chamber in a natural fall-off manner; (2) injecting the gypsum product, which is selected to be below a predetermined particle size in the first chamber, into the second chamber by using the air suction force; (3) Fine particles in the gypsum product having a predetermined particle size or less introduced into the second chamber are raised by the continuous air suction force to be collected at the third chamber side, and a predetermined -65 mesh is formed at the lower portion of the second chamber by its own weight. Selecting purified gypsum having a particle size range of ˜ + 200 mesh; (4) extracting the purified gypsum product selected in the second chamber; purification method of phosphate gypsum characterized in that it comprises a. delete delete delete