DE2944388A1 - IRON METAL GROUP - Google Patents

Description

2 9 '^; Μΰ8

- 3 DESCRIPTION

The invention relates to a ferrous metal barrow and a method for its production. The invention also relates to the use of ferrous metal barley for the production of radiation protection concrete.

As is well known, the growing demand for energy has led to the rapid development of nuclear power plants. Use of the Nuclear energy, however, requires a simultaneous development of protective measures against those dangerous for the human body Radiation, especially gamma radiation and secondary neutron radiation.

For the isolation of fissile materials, materials were previously used in such power plants or for the storage of radioactive materials used to absorb radiation, initially heavy metals and later concrete was used to make the high Exploiting the mechanical strength of the concrete combined with specific properties in terms of radiation absorption .

About the shielding properties of the concrete against gamma radiation and to increase neutron radiation, efforts have been made to increase its density, particularly by adding scrap metal or scrap, in connection with various heavy compounds such as barite, magnetite and in some cases also limonite.

In order to improve the capture of neutrons, it has also already been proposed to realize very heavy types of concrete, in that, in addition to the scrap input, compounds with a large effective surface were incorporated, in particular if possible, water-containing boron ores (colemanite, pandermite or boron calcite).

030020/0811

ORIGINAL INSPECTED

294A388

For example, types of concrete have already been proposed in which a combination of scrap, iron barley and a boron-containing Ore (especially colemanite) were incorporated, the latter with an amount corresponding to about 1% pure boron in relation to the total weight of the concrete. In other cases only iron barley and one containing boron were found Ore used.

It is known, however, that the addition of boron compounds to concrete is not without its disadvantages: on the one hand, it improves the setting behavior of the cement changed and on the other hand the density of the concrete is due to the very low density of the boron ores too low compared to scrap. If the concrete is poured under the action of vibration, the light, parts contained therein, so the boron compounds, the tendency to rise in mass, resulting in a heterogeneous Structure leads, moreover also leads to the addition of various Types of components to the cement to an increase in production costs, since then more storage containers and more extensive Handling is required (FR-PS 1 458 833).

The object of the invention is to create an additive for concrete that has both a high density and is used for braking of gamma rays is suitable as well as a large cross section has to capture the thermal neutrons.

This object is achieved by a ferrous barley, in particular cast iron barley, which according to the invention contains 0.1 to 5% by weight Contains boron.

According to the invention, the use of this barley as an additive for concrete for the absorption of radioactive radiation is also possible suggested.

030020/081 1

29 / "'388

The method according to the invention for producing the pearl barley is characterized in that the metal of this barley is produced in a cupola furnace in a manner known per se and a boron compound is fed into the cupola, preferably an ore containing boron.

Ferrous barley or cast iron barley is to be understood as meaning all barley made of ferrous metals, at most Contain 4% by weight of carbon.

According to a preferred embodiment, the pearl barley is off formed a mixture of grains of different dimensions in order to achieve a filling of cavities that of the corresponds to the desired overall density. A density of up to 6 can be achieved without difficulty.

According to a particular embodiment, the pearl bar has a Size distribution according to the sieve numbers 38 to 17 of the AFNOR standard, corresponding to diameters from 5 mm to 0.040 mm and the grain size numbers 0 to 100. The barley grains can be round or, if necessary, ground to the To meet grain size requirements.

In order to achieve the desired compactness, the grain size composition realized by different weight proportions of grains of different sizes, as in the Technology is known, e.g. with two numbers 0-16 or three numbers 0-16-50 or 0-100 or with four numbers O-16-5O-100.

The pearl bar according to the invention has according to a particular embodiment following composition (% by weight):

Carbon 0.1-4

Silicon 0.2 - 2

030020/081 1

ORIGINAL INSPECTED

294U88

Phosphorus 0.05 - 1

Manganese 0.1 - 1

Sulfur 0.05 - 1

Boron 0.1-5

It is noted that it is already known in the art to incorporate boron into iron barley, but with a different one Objective (to improve hardenability by quenching) and in much smaller proportions (in of the order of a few parts per million).

According to the method according to the invention, the barley is in one Cupola manufactured by manufacturing processes known per se, by feeding a boron compound, preferably an ore containing boron, into the cupola.

Ores such as colemanite, pandermite or boron calcite or the like Containing 40 - 50% boron oxide are fed through the nozzles into the cupola, either into all of the nozzles common wind pipe or directly into one or more nozzles. For this purpose, a spray device is used for spraying used with air under adjustable pressure, which takes the ore with it in the form of a powder or granules.

For example, to achieve 1% boron in the metal that forms the barley, 75 kg of colemanite with a boron content of 13.6% are added per ton, without taking losses into account.

This manufacturing process makes it possible to produce a spray known amount in such a zone that the efficiency stays good. An addition through the furnace furnace would cause a high loss through smoke formation and gases, while an addition through the tapping channel or through the pan leads to too high an irregularity of the percentage Boron content and the appearance of slag, which is difficult to remove and would contaminate the product.

030020/0811

2 9 Λ / -388

According to the method according to the invention, another Boron compound can be used as an ore, e.g., iron boron. However, such an alloy is very expensive, which is why theirs Use is only possible to a limited extent, whether in a cupola furnace or when melting in an electric arc furnace or after melting.

The production of the actual grain by comminuting the metal beam is a process known per se, whereby however, it should be noted that a sufficiently wide range of diameter sizes are manufactured in balanced quantities must in order to meet the grain size and density requirements. The tuning of the final grain size relationships can be done by The round pearl barley is sorted and selected according to the numbers taken into account, with ground pearl barley being added can be; these process steps are well known in the art.

In the radiation protection concrete for nuclear power plants or storage containers for radioactive substances, such an amount is according to the invention Graupe incorporated that the concrete has a density of the order of 5.3 to 6.

According to a particular embodiment, the concrete has a Total dry density of 5.95 and the following composition:

Cement: 350 kg

Graupe with four
Grain sizes
(0, 16, 50, 100): 5530 kg

Water: 150 kg.

As an example for comparison, a radiation protection concrete with a total dry density of 5.3 according to the known method is used made by mixing the following ingredients:

Cement: 400 kg

Borer ore (colemanite): 400 kg Graupe: 1500 kg

030020/081 1

Scrap: 3000 kg

Water: 150 kg.

The pearl bar according to the invention thus enables a significant one Reduction of the number of components used in the manufacture of concrete or mortar to absorb nuclear radiation, while at the same time reducing the number of manipulations and storage containers, resulting in a significant reduction the production costs for such a concrete leads "

O 3 00 * 0 / oiH

Claims (6)

PATENT ADVOCATE DIPL.-PHYS. LUTZ H. PRÜFER · D-8OOO MUNICH ACIERIES THOME-CROMBACK Paris / France Eisenmetallgraupe PATENT CLAIMS 1. Ferrous barley, characterized by a content of 0.1 to 5 wt .-% boron. 2. pearl barley according to claim 1, characterized in that it contains the following elements: Carbon 0.1 - 4% by weight Silicon 0.2-2% by weight Phosphorus 0.05 - 1% by weight Manganese 0.1 - 1% by weight Sulfur 0.05-1% by weight Boron 0.1-5% by weight PATENT ADVOCATE DIPL.-PHYS. UUTZ H. PRÜFER ■ D-8OOO MUNICH 9O · WILLROIDERSTR. β * TEL. (Ο89) 64064O 0300 2 0/0811 29U388 3. Graupe according to claim 1 or 2, characterized by its use as an additive for high-density concrete for protection against nuclear radiation. 4. grain according to claim 3 / characterized in that the concrete has a density between 5.3 after adding the grain and 6 has. 5. The method for producing a pearl bar according to claim 1 or 2, characterized in that the metal of this Graupe is produced in a known manner in the cupola and a boron compound, in particular, in the cupola an ore containing boron is fed. 6. The method according to claim 5, characterized in that the boron compound is fed into the nozzles of the cupola furnace will. 030020/081 1