JPH05169187A - Method for treating molding sand - Google Patents

Abstract

PURPOSE:To provide a molding sand treating method, which can correspond to the various kinds of sands having different composition recovered from a molding line and obtains unformized sand without distribution in the sand quality. CONSTITUTION:Since a first sand near a casting product in a master mold changes the composition by burning, after the removal of the foreign matter and a cooling process 83 of the sand are completed, by applying kneading 84 to be the first adding process of clay, moisture, etc., the quality is stabilized in some extent. Thereafter, the treated sand is joined into a second sand treating line X which is not affected from a casting product and for which the change of the composition is not generated and by applying the main kneading in the first kneading process 74 to the second sand, the stabilization of the quality of the first sand is surely attained together with the second sand. Further, a bypass line Z from a molding line is joined at the most upstream side of a treating line Y, and by introducing the shake-out of the sand in the next day generated on the operation of the treating line into the treating line Y, the stabilization of the quality to a third sand is surely attained.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to an efficient method of treating foundry sand used to make foundry.

[0002]

2. Description of the Related Art Generally, foundry sand used for casting foundries is recovered after casting, treated for reuse, and recycled. Here, the state of sand in the casting main mold will be described (see FIGS. 2, 3, 4, and 5). The molten metal is supplied to the shaped portion 51 formed in the main mold 50 filled with the main mold sand 55 through the runner 53 to form the cast product 52. The temperature of the molten metal is 1350 ° C to 1450
At a high temperature of ℃, in a normal molding line, the product is taken out after being cooled in the mold for about 1 hour. The first sand 54 adheres to the cast product 52 that has been taken out and has been heated to a temperature of 500 to 700 ° C. The first sand 54 occupies 10 to 20% of the total amount of sand, and the high temperature casting product 52
By contact with, the water content was removed and the clay content was altered. In addition, the main mold 5 after the casting 52 is taken out
Within 0, the second sand 56 (80-90% of the total sand)
Remains. Since the second sand 56 was at a distance from the high temperature casting 52, it was not affected by heat, and the composition of the sand remained almost as it was during molding.

FIG. 6 shows a basic method of sand treatment of a casting which has been conventionally performed. First, all the sand of the main mold used for casting in the molding line is recovered, and the iron piece separation treatment 1
1. After crushing sand and sieving to separate foreign substances 12, cooling 13, time adjustment 14 in a sand tank, through preliminary kneading step 15 for supplying water, pentonite and an appropriate amount of dust, The material was conditioned 16 for a certain period of time, and a main kneading step 17 of replenishing additives and water was carried out and circulated in the molding line. However, since this method is a method in which the entire amount of the first sand 54 and the second sand 56 is passed through the pre-kneading step 15, the kneading of the light sand is light according to the second sand 56 which accounts for 80 to 90% of the total amount of the sand. Was dealt with by doing. However, it is difficult to deal with the first sand 54 whose sand composition changes drastically, and the quality of the sand circulated in the molding line varies, making it difficult to make the quality of the sand uniform.

Therefore, in Japanese Patent Laid-Open No. 63-317232, the sand of the main mold is separated into a first sand 54 attached to a casting and a second sand 56, which are separately collected, and the treatment lines are separated from each other. Is disclosed (see FIG. 7). That is, the first sand 54 burnt at the high temperature is processed in the processing line A. The second sand 56 remaining in the main mold is processed in the processing line B. The processing lines A and B constitute separate processing lines up to the preliminary kneading step 15 and the culturing step 16, and in the main kneading step 17, both sands 54 and 56 are kneaded together and circulated to the molding line.

[0005]

However, in the disclosed invention, since the pre-kneading step is also present in the treatment line B for treating the sand whose composition does not change so much, a wide space is required for installing the treatment line. It was uneconomical in terms of capital investment. In addition to the distance from the casting shape 51, the influence on the properties of the sand 55 of the main mold is related to the operating condition of the line. In other words, the condition of sand changes depending on whether the line is in continuous operation or it will be broken the next day. The next day Barashi is 12 to 4 after casting from the operational status of the line.
It means a state where the frame is removed after 8 hours. When the line is operated continuously, the above-mentioned first sand 54 and second sand 56
However, in the case of disintegration the next day, heat is transferred to the second sand and the entire main mold 50 is burned (see FIG. 5). That is, the next day's second sand 56 'is quite hot. The disclosed invention does not take into consideration the third sand 56 'that is generated from the molding line of the next day, which is burned to remove moisture and the clay component is altered. Therefore, the present invention can be applied to the first sand, the second sand, and the next day's sand that is recovered from all molding lines, and a sand processing method for a casting that can obtain uniform sand with no variation in sand quality. Is provided.

[0006]

The method for treating foundry sand according to the present invention comprises a step of removing foreign matters, a step of cooling sand, and a main kneading step. The sand treatment of the first sand having a composition change in the vicinity of the casting, which is provided with a second sand treatment line for untreated sand, a step of removing foreign matter, a step of cooling the sand, and a sub-kneading step. A line is provided, the first sand treatment line is joined to the main kneading process of the second sand treatment line after the sub-kneading process is completed, and at the upstream side of the iron separation process of the first sand treatment line, from the molding line. The bypass line is merged.

[0007]

The casting sand, which has a substantially constant sand composition with a distance from the casting, is re-used by replenishing clay, water, etc. in one main kneading step. The first sand, which has been burned to a high temperature near the casting, is replenished with clay, moisture, etc. in the sub-kneading step, the composition of the sand is once stabilized, and then mixed with the second sand to undergo the main kneading step. Therefore, it is possible to reliably deal with variations in sand quality. On the next day, sand having a sharp composition change such as disintegration is joined to the first sand treatment line by a bypass line.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described with reference to the drawings. There are three types of sand recovered from the molding line. Burnt first sand 54 around the casting 52 (10-20% of the total amount of sand) Unburned second sand 56 away from the casting 52
(80-90% of the total amount of sand) Third sand 56 ', which is all main type sand burnt in the Balashi line on the next day (3% -6% of the total monthly sand treatment amount) FIG. It is explanatory drawing of the sand processing line with respect to sand. The cast product 52 formed in the main mold 50 is taken out after being cooled in the mold. The cast product 52 taken out with the first sand 54 attached thereto is shot blasted on the turntable to be separated into the cast product 52 and the first sand 54, and the cast product 52 is cooled. Transferred to a bucket. The first sand 54 separated from the casting product 52 in the turntable and the second sand 56 remaining in the main mold 50 are separately collected, and separate sand treatment line X and sand treatment line are provided. Y
Is processed by.

Sand Treatment Line X The sand treatment line X is a line for treating the second sand 56. In the iron piece separating step 71, the iron pieces of the second sand 56 are
In the crushing and sieving step 72, shells, lumps, shots, etc. are separated. Then, the second sand 56 is cooled in the sand cooler step 73, and water, pentonite (clay), lime powder, cone starch and the like are added in the main kneading step 74. Then, the conditioning in the tank (main storage
Step 75) It is conditioned for a certain period of time and swelled with added clay or the like, and circulated as molding sand in the molding line.

Sand Treatment Line Y The sand treatment line Y is a line for treating the first sand 54 with. The recovered first sand 54 is separated into an iron piece, a shell and a lump in an iron piece separating step 81, a sand crushing and sieving step 82. The sand is cooled in the sand cooler step 83, and water, pentonite, etc. are added in the sub-kneading step 84. It is conditioned in the tank (sub storage process) 85, and water, pentonite (clay), lime powder, cone starch, etc. are added in the main kneading process 74 of the sand treatment line X, and the main storage is performed. In step 75, it is conditioned for a certain period of time. And the second
It is circulated to the molding line together with the sand 56 as molding sand.

Bypass line Z The third sand 55 'which will be removed the next day is processed by the bypass line Z. The bypass line Z is composed of a sand conveying means such as a belt conveyor, and a tank 92 for adjusting the amount of sand generated instantaneously. The third sand 56 ′ conveyed by the sand conveying means is supplied to the molding line Y before the iron piece separating step 81 of the molding line Y together with the first sand 54 whose composition is changed to the same degree, and is crushed by sand. Sieving step 82,
Sand cooler step 83, sub-kneading step 84, sub-strain
Main kneading step 7 of sand treatment line X
4 is supplied.

According to the sand treatment method thus constructed, the preliminary kneader is removed from the sand treatment line X for treating the second sand 56, which accounts for 80 to 90% of the total amount of the sand and the composition of the sand is almost unchanged. However, by using only this kneader, the space is saved and the capital investment is reduced. In addition, the first sand 54, which has been burned and deteriorated in quality, is treated in the sand treatment line Y which is a sub-line, and the first sub-kneading step 84 is performed.
Is completed and the composition of the sand is recovered, the sand is re-supplied to the kneading step 75 of the sand processing line X of the main line and kneading is performed. Receives kneading to ensure stable quality. Furthermore, since the amount of the third sand 56 'that is supplied to the sand processing line the next day is small, a bypass line Z having a simple structure is provided and is supplied to the sand processing line Y. Then, since it passes through the first sub-kneading step 84 together with the first sand 54, it is supplied to the main line after the quality is stabilized in the same manner as the first sand 54 having a sharp composition change.

In the conventional main sand treatment, the sand that causes quality variations, that is, the first sand 54 burnt around the casting 52 and the third sand 56 'which is scattered the next day.
Note that the amount of sand is small relative to the total amount of sand, and after passing a small amount of these sands through the sub-line and kneading once to stabilize the quality, it is re-applied to the sand treatment line X, which is the main line. By supplying it, the quality of sand is uniformly stabilized.

[0014]

According to the method for treating foundry sand of the present invention, sand having a drastic composition change in the vicinity of the foundry is first supplied with clay, moisture, etc. in the sub-kneading step to stabilize the composition to some extent. Since it joins the kneading process and is replenished with clay and water, the quality can be reliably stabilized. Further, the composition of sand, which is separated from the casting and has a small compositional change, can be sufficiently stabilized in composition by adding clay, water and the like in one kneading step.

Further, it takes 12 to 24 hours after the addition in order for the clay content added in the kneading step to swell and exert its effect, and the tank for conditioning should be of a size corresponding to the amount of sand. Needed. However, in the method of the present invention, since the second sand processing line, which has to process a large amount of sand, ensures reliable stabilization of sand in one kneading step, one large tank is used. OK. On the other hand, since the amount of the first sand is small, the equipment in the first sand treatment line can be small, and the entire treatment line achieves space saving and economical capital investment.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a sand treatment line according to the present invention.

FIG. 2 is an explanatory view of the state of sand in the main mold.

FIG. 3 is an explanatory view of the state of sand in the main mold.

FIG. 4 is an explanatory view of the state of sand in the main mold.

FIG. 5 is an explanatory view of the state of sand in the main mold in the case of disintegration the next day.

FIG. 6 is an explanatory view of a conventional sand processing line.

FIG. 7 is an explanatory view showing another conventional example of a sand processing line.

[Explanation of symbols]

 50 Main mold 52 Cast product 54 First sand 56 Second sand 71, 81 Iron piece separation process 72, 82 Sand crushing and sieving process 73, 83 Sand chiller process 74 Main kneading process 75 Main storage process 84 Sub-kneading process 85 Sub-storage process X Second sand treatment line Y First sand treatment line Z Bypass line

Claims (1)

[Claims] 1. A first sand in the vicinity of a casting, the composition of which has changed, and a second sand, which is separated from the casting and has almost no change in composition, are collected separately and converted into a molding line by another processing line. In the circulating molding sand treatment method, the second sand treatment line includes a step of removing foreign matter, a step of cooling sand, and a main kneading step, and the first sand treatment line removes foreign matter. The first sand treatment line includes a step, a step of cooling sand, and a sub-kneading step, and the first sand treatment line is joined to the main kneading step of the second sand treatment line after the sub-kneading step is completed. A method for treating foundry sand, in which a bypass line from the molding line is joined upstream of the iron separation process of the line.