JPH09257785A - Analysis of composition of foundry sand sample - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately calculate both analytical values within a short time by obtaining the solid carbon analytical value of a foundary sand sample by performing a carbon measuring method in a solid carbon measuring process while perfectly burning the foundry sand sample in a combustion furnace in an ignition loss measuring process in succession to the solid carbon measuring process to obtain the ignition loss analytical value of the foundary sand sample on the basis of loss of wt. SOLUTION: In a drying process, a sample 1 is put in a container 2 to be dried by using an infrared lamp 3 and, in a next cooling process, the sample 1 is cooled along with the container. Next, the sample 1 is weighed by a spoon 4 in a weighing process and subsequently ground by using a vibration grinder 5. Next, in an analyzing process, a board 6 is heated in a combustion furnace 7 and generated carbon monoxide and carbon dioxide are guided to an analyzer 8 and the generation amt. of gas is measured by a data processor 9 to obtain the analytical value of the sample 1.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for analyzing the composition of a foundry sand sample obtained from foundry sand.

[0002]

2. Description of the Related Art When molding a mold mainly used for producing cast iron castings, for example, for a green mold, silica sand and a binder made of activated clay such as bentonite, and an additive such as coal powder or starch are used. Molding is performed by using raw sand obtained by kneading a predetermined amount by a kneader, and molding is performed by using a mixture of silica sand and resin for the shell mold.

The foundry sand obtained by the separation is
A binder and the like are again added in a predetermined amount, and generally used repeatedly as molding sand. At this time, the molding sand contains any fixed carbon content (FC), ignition loss (IL), activated clay content (A).
If it is not clear that the composition is C), the amount of starch, the amount of organic resin, etc., the amount of the binder, etc. for re-preparing the foundry sand cannot be determined, and a molding sand having an accurate desired composition can be obtained. Since it does not exist, it becomes difficult to form a mold having stable strength. For this reason, composition analysis of foundry sand is an important factor for suitable molding of a mold.

In the conventional chemical composition analysis method for FC and IL of foundry sand, a foundry sand sample is obtained, and as shown in FIG. 2, first, as a pretreatment step, (A) a drying step is performed. , (B) cooling step, (C) weighing step, (D) crushing step, and (E) weighing step. Then, as the analysis process, (F) combustion process, (G)
The cooling / measurement process, (H) combustion process, and (I) cooling / measurement process are sequentially executed. Here, the solid carbon content analysis value is obtained by the (F) combustion step and the (G) cooling / measurement step. Further, the ignition loss analysis value is obtained by the (F) combustion step, the (H) combustion step, and the (I) cooling / measurement step.

Based on the thus obtained solid carbon content analysis value and the like, the addition amount of the binder or the like to be kneaded is set, and the molding sand is re-prepared. Then, new molding is performed using the obtained molding sand, and pouring is performed. After this, dispersal and the like are repeated again. In addition, in the field where sea and river sediments are subject to inspection, a small amount of solid sample is heated in a combustion furnace and the amount of carbon monoxide and carbon dioxide gas generated is measured with an infrared gas analyzer, etc. There is known a carbon measuring method for obtaining a solid carbon content analysis value of a solid sample.

[0006]

However, the above-mentioned conventional F
In the chemical composition analysis method of C and IL, the casting sand sample is once cooled to obtain the solid carbon content analysis value, and then burnt again to obtain the ignition loss analysis value. It needed a degree and took a long time.

In this respect, it is considered that the composition analysis of the foundry sand sample can be completed in a short time by applying the above carbon measuring method to the composition analysis method of the foundry sand sample. Certainly, since the carbon measurement method obtains an analysis value for carbon, if a foundry sand sample that is dried and crushed and weighed to a predetermined amount is used as a solid sample, the solid carbon content analysis of the foundry sand sample is performed. The value is obtained. Moreover, the solid carbon content analysis value is highly accurate because it contains only one element of carbon.

However, in the conventional carbon measuring method, when the amount of gas generated such as carbon monoxide gas to be analyzed is saturated, heating and measurement of the amount of gas generated are stopped there, and the solid sample is discarded. In addition, the ignition loss analysis values of the foundry sand samples are hydrocarbon, hydrogen, carbon monoxide,
It is measured including all carbon dioxide, sulfur sulfide, ammonia, benzene, tar and other volatile substances at high temperatures. For this reason, the carbon measurement method was applied to
It is difficult to apply it to the L analysis method as it is, because analysis of only one carbon element is not sufficient. Further, even if it is possible to analyze multi-elements by a combination of methods similar to the carbon measurement method, errors will be accumulated and the accuracy of analysis will be deteriorated.

The present invention has been made in view of the above-mentioned conventional circumstances, and it is an object to be solved to accurately obtain a solid carbon content analysis value and an ignition loss reduction analysis value in a short time.

[0010]

[Means for Solving the Problems]

(1) The composition analysis method for a foundry sand sample according to claim 1, wherein the foundry sand sample that has been dried and pulverized and weighed to a predetermined amount is heated in a combustion furnace, and the generated carbon monoxide and carbon dioxide gas amounts are generated. A fixed carbon content measuring step for obtaining a solid carbon content analysis value of the foundry sand sample by measuring
A continuous ignition from the fixed carbon content measuring step, a complete burning of the foundry sand sample in the combustion furnace, and an ignition loss measuring step of obtaining an ignition loss analysis value of the foundry sand sample by weight loss. And

In the composition analysis method of the first aspect, the carbon measurement method is executed in the fixed carbon content measurement step to obtain a solid carbon content analysis value of the foundry sand sample. Here, the solid carbon content analysis value obtained by the carbon measurement method is highly accurate because it is only one element of carbon. Then, in the ignition loss measurement step, the foundry sand sample is completely burned in the combustion furnace continuously from the fixed carbon content measurement step, and the gas generation amount of carbon monoxide gas or the like to be analyzed in the fixed carbon content measurement step is saturated. After that, continue to heat the foundry sand sample until other types of gas generation are saturated. Here, the ignition loss analysis value involving multiple elements can be obtained with high accuracy by subtracting the weight of the foundry sand sample after complete combustion from the weight of the foundry sand sample before the fixed carbon content measurement step.

Thus, in this composition analysis method, solid carbon content analysis value and ignition loss analysis value are obtained by continuously heating the foundry sand sample without cooling, and the composition analysis of the foundry sand sample is performed in a short time. You can finish with. Also, its accuracy is good. (2) The composition analysis method for a foundry sand sample according to claim 2 is the composition analysis method for a foundry sand sample according to claim 1, wherein
At least one of the fixed carbon content measuring step and the ignition loss measuring step is characterized by being performed in an atmosphere in which oxygen is actively supplied.

According to the composition analysis method of the second aspect, at least one of the fixed carbon content measuring step and the ignition loss measuring step is executed in an atmosphere in which oxygen is positively supplied, so that the combustion time of these steps is shortened. It

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments embodying the inventions of claims 1 and 2 will be described below together with comparative embodiments. (Embodiment) A foundry sand sample is acquired, and the following pretreatment process and analysis process are performed on the foundry sand sample as shown in FIG. 1.

"Pretreatment Step" First, as a drying step (A), 20 g of a molding sand sample 1 is put in a container 2 and an infrared lamp 3 is used to dry the molding sand sample 1 at a temperature of 160 ° C. The time required for this is 3 minutes. next,
(B) In the cooling step, the foundry sand sample 1 is allowed to cool in the atmosphere together with the container 2 to cool the foundry sand sample 1. The time required for this is 1 minute.

Then, as the (C) weighing step, 10 g of the foundry sand sample 1 is weighed with the spoon 4. The time required for this is 1 minute. Next, as the (D) crushing step,
The vibration sand mill 5 is used to grind the foundry sand sample 1. The time required for this is 1 minute. Then, in the (E) weighing step, 0.3 ± 0.0001 g of the molding sand sample 1 is weighed with the spoon 4 and put into the alumina boat 6.
The time required for this is 1 minute.

[Analyzing Step] First, as the (F) fixed carbon content measuring step, the boat 6 is placed in the combustion furnace 7 and the foundry sand sample 1 is heated in the combustion furnace 7 at 980 ° C. At this time, oxygen is positively supplied. The generated carbon monoxide and carbon dioxide are guided to the infrared gas analyzer 8, and the amount of generated gas is measured by the data processing device 9. Thus, the solid carbon content analysis value of the foundry sand sample 1 is obtained. The obtained solid carbon content analysis value was highly accurate because it contained only one carbon element. The time required for this is 5 minutes.

Then, as the (FG) ignition loss measuring step, the foundry sand sample 1 is completely combusted in the combustion furnace 7 continuously from the (F) fixed carbon measuring step, and the (F) fixed carbon measuring is performed. Even after the gas generation amount of the carbon monoxide gas or the like to be analyzed is saturated in the process, the foundry sand sample 1 is continuously heated until the gas generation amounts of other types are saturated. The foundry sand sample 1 is left to cool in the air together with the boat 6, and the foundry sand sample 1 is cooled. After cooling to room temperature, the foundry sand sample 1 is weighed together with the boat 6 and subtracted from the weight of the foundry sand sample 1 before the (F) fixed carbon content measurement step to obtain the weight loss due to complete combustion. By this weight loss, the ignition loss analysis value involving many elements can be obtained with high accuracy. (G) heating,
The time required for air cooling and measurement is 10 minutes.

Thus, in this composition analysis method, the solid sand carbon content analysis value and the ignition loss analysis value are obtained by continuously heating the foundry sand sample 1 without cooling, and the composition analysis of the foundry sand sample 1 is performed. 22 minutes, 1 in analysis process only
It can be completed in 6 minutes. Also, its accuracy is good. (Comparative embodiment) A foundry sand sample is obtained, and the following pretreatment process and analysis process are performed on the foundry sand sample, as shown in FIG. 2.

"Pretreatment Step" First, as a drying step (A), 200 g of a molding sand sample 1 is put in a container 2 and the molding sand sample 1 is dried at a temperature of 100 ° C. in a hot air circulation type drying furnace 10. To do. The time required for this is 60 minutes. Next, in the cooling step (B), the foundry sand sample 1 is left to cool in the air together with the container 2, and the foundry sand sample 1 is cooled. The time required for this is 30 minutes.

Then, as the (C) weighing step, after scraping off the pile of the foundry sand sample 1 in the container 2, 10 g of the foundry sand sample 1 is weighed with the spoon 4. The time required for this is 1 minute. Next, as the (D) crushing step,
The foundry sand sample 1 is crushed by the mortar 11a and the pestle 11b of the lightning destroyer 11. The time required for this is 10 minutes.

Then, (E) as a weighing step, 1 ± 0.0001 g of the molding sand sample 1 is weighed with a spoon 4,
Place in an alumina crucible 12. The time required for this is 1
It's a minute. [Analysis Step] First, as the (F) combustion step, the alumina lid 12a is covered on the crucible 12, these are placed in the electric furnace 13 and heated at 1000 ° C. The time required for this is 3 minutes.

Next, in the cooling and measuring step (G), the crucible 12 covered with the lid 12a is cooled in the atmosphere. After cooling to room temperature, weigh the crucible 12 covered with the lid 12a,
(F) The solid carbon content analysis value is obtained by the reduction from the weight before the combustion step. The time required for this is 31 minutes. Then, as the (H) combustion step, these are put again in the electric furnace 13 and heated at 1000 ° C. At this time, the lid 12a is opened and the crucible 12 is placed on it. The time required for this is 60 minutes.

Next, in the cooling / measuring step (I), the crucible 12 together with the lid 12a is left to cool in the atmosphere. After cooling to room temperature, the crucible 12 is weighed together with the lid 12a, and the weight loss from the weight before the combustion step (F) is obtained to obtain an ignition loss analysis value. The time required for this is 31 minutes. In this way, although this composition analysis method can obtain accurate solid carbon content analysis values and ignition loss analysis values, it took 227 minutes and 125 minutes in the analysis step alone.

[0025]

As described above in detail, in the composition analysis method for the foundry sand sample according to the first and second aspects, the solid carbon content analysis value and the ignition loss analysis value of the foundry sand sample are accurately obtained in a short time. be able to. Therefore, according to this composition analysis method, it is possible to thoroughly manage the casting sand, reduce the defective products associated therewith, and reduce the manufacturing cost.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a composition analysis method according to an embodiment.

FIG. 2 is a schematic diagram showing a composition analysis method of a comparative form.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiromi Tomishige 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Yasunori Yamamoto 1 Shino Nishi Goshodacho, Kita-ku, Kyoto City, Kyoto Prefecture Shimano Plant, Shino Plant (72) Inventor, Go Iwamoto, No. 1, Shino Nishigoshota-cho, Kita-ku, Kyoto City, Kyoto Prefecture Shimazu Plant, Shino Plant

Claims (2)

[Claims] 1. A solid of a foundry sand sample, which is obtained by heating a foundry sand sample that has been dried and crushed and weighed to a predetermined amount in a combustion furnace, and measuring the amount of generated carbon monoxide and carbon dioxide gas. A fixed carbon content measurement step of obtaining a carbon content analysis value, and the foundry sand sample is completely combusted in the combustion furnace continuously from the fixed carbon content measurement step, and the ignition loss analysis value of the foundry sand sample is reduced by weight reduction. And a step of measuring loss on ignition to obtain a composition analysis method of a foundry sand sample. 2. The method for analyzing the composition of a foundry sand sample according to claim 1, wherein at least one of the fixed carbon content measuring step and the ignition loss measuring step is executed in an atmosphere in which oxygen is actively supplied. .