Production of a manganese oxide suitable for the production of ferrites
Document Number
GB Patent 951037
Publication Date
1964-03-04
Link
Inventors
not available
Abstract
Abstract of
GB951037
Manganese oxide suitable for the production of ferrites is obtained by heating pulverized manganese in pure water at a temperature up to 100 DEG C. until all the water is evaporated. The dry product may be further heated at a temperature of about 150 DEG C. for several hours. The manganese starting material may be prepared electrolytically, and the average particle size after grinding and pulverizing may be about 3 microns. Distilled or condensed water may be used for the initial heating, and may be used in amounts of at least 5 litres of water per kg. of manganese. The product may be of formula Mn2O3.
Production of a manganese oxide suitable for the production of ferrites
Inventor: BERGMANN DR FRIEDRICH; SCHNEIDER DR GUSTAV; (+1)
Applicant: BASF AG
EC:C01G45/02; C04B35/26; (+3)
IPC: C01G45/02; C04B35/26; C22B47/00(+5)
Publication info: DE1149341 B - 1963-05-30
2
Production of a manganese oxide suitable for the production of ferrites
Inventor:
Applicant: BASF AG
EC:C01G45/02; C04B35/26; (+3)
IPC: C01G45/02; C04B35/26; C22B47/00(+5)
Publication info: GB951037 A - 1964-03-04
List of citing documents
Claims
WHAT WE CLAIM IS:-
1. A process for the production of a manganese oxide suitable for the production of ferrites, by oxidation of metallic manganese with water, wherein manganese is pulverised to a fine powder and heated with added pure water at temperatures up to about 1000 C.
until the whole of the water has evaporated.
2. A process as claimed in claim 1 wherein the powder obtained is heated for several hours at a temperature up to about 150' C.
3. A process as claimed in claim 1 or 2 wherein the size reduction of the manganese is carried out in the presence of water.
4. A process as claimed in any of claims 1 to 3 wherein the manganese used is prepared electrolytically.
5. A process as claimed in any of claims 1 to 4 wherein the water used is distilled water or condensed water.
6. A process as claimed in any of claims 1 to 5 wherein the manganese is reduced in size to an average particle size of about 3 microns.
7. A process as claimed in any of claims 1 to 6 wherein the water is added in an amount of at least 5 litres per kg of manganese.
8. The process for the production of manganese oxide substantially as described in either of the foregoing Examples.
9. Manganese oxide when obtained by the process claimed in any of claims 1 to 8.
J. Y. & G. W. JOHNSON, 47, Lincoln's Inn Fields, London, W.C.2, Chartered Patent Agents, Agents for the Applicants.
Leamington Spa: Printed for Her Maiesty's Stationery Office by the Courier Press.-1964.
Published at The Patent Office. 25, Southampton Buildings, London, W.C.2, from which copies may be obtained.
951,037
Description
PATENT
SPECIFICATION
NO DRAWINGS 951,037 Date of Application and filing Complete Specification Sept. 26, 1962.
No. 36491/62.
Application made in Germany (No. B64171 IVa/12n) on Sept. 28, 1961.
Complete Specification Published March 4, 1964.
Crown Copyright 1964.
The inventors of this invention in the sense of being the actual devisers thereof within the meaning of Section 16 of the Patents Act, 1949 are Friedrich Bergmann, Gustav Schneider and Hermann Walther, citizens of Germany, residing, respectively, at 15 Brunckstrasse, Ludwigshafen/Rhein, Germany; 18 Ungsteiner Strasse, Ludwigshafen/Rhein, Germany and 12 Doerrhorststrasse, Ludwigshafen/Rhein, Germany.
Index at acceptance: -Cl AN20 International Classification:-C 01 g COMPLETE SPECIFICATION
Production of a Manganese Oxide Suitable for the Production of Ferrites We, BADISCHE ANILIN- & SODA-FABRIH AKTIENGESELLSCHAFT, a German Joint Stock Company of Ludwigshafen/,Rhein, Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following Statement:-
Ferrites are used to a considerable extent in electrical engineering by reason of their special magnetic and electrical properties.
They are used inter alia as cores for coils for alternating current, for example filter coils, Pupin coils, transmission cores, and high frequency cores, as magnetic storage cores and also, if they do not have a cubic structure, as permanent magnets.
It is known to prepare ferrites by mixing ferrite-forming metal oxides intimately, pressing the oxide mixture into the desired core mould, if desired after one or more preliminary sinterings and subsequent size reductions, and subjecting them to a final sintering at temperatures between about 1100 and 1300 C. Ferrites may also be prepared by melting together a powder mixture consisting of powders of the metals the oxides of which form the ferrite, and which may be partly replaced by metal oxide powder, in an oxygencontaining atmosphere to form the desired ferrite, or causing an oxide mixture to melt by electric resistance heating, and then allowing the product to cool.
Among known ferrites, manganese-zinc Price 4s. 6d.] ferrites are characterised by special magnetic properties, such as high permeability values and low alternating current losses, particularly low hysteresis losses. To achieve these special properties, the initial materials used, especially the manganese oxide, must have a high degree of purity and sufficient activity.
It is however difficult to prepare such pure manganese oxide. According to one known method, metal oxides, particularly those of manganese and iron, which are suitable for the production of ferrites, can be obtained by treating the metal powder at temperatures of about 400 C. for several hours with steam, grinding the resultant product in the presence of distilled water, drying it and finally calcining it at temperatures of 500 C. for several hours with free access of air.
In the production of manganese ferrites it is however also. possible to start from other manganese compounds such as manganous oxalate or carbonate. Such compounds are troublesome to prepare and moreover require a higher expenditure of labour to process them into ferrites because of their lower content of manganese.
We have now found that a very pure and active manganese oxide, suitable for the production of ferrites, can be prepared by grinding pure manganese metal to a fine powder, heating this powder, after adding pure water, at temperatures up to about 100 C. until the whole of the water has evaporated.
Manganese metal which has been prepared hO mR by electrolytic methods is especially suitable as initial material for carrying out the process according to this invention. Size reduction of the metal may take place in a ball mill or the -like and it is advantageous to carry out the grinding process in the presence of water, part of the metal thereby being converted into oxide. To avoid contamination of the metal it is recommendable to use distilled water or condensed water. The metal is reduced in size to a mean particle size of about 3 microns. Then water in an amount of at least 5 litres per kg of manganese is added to the metal powder, which may contain some oxide, the whole then being heated at temperatures of 70 to 100 C., advantageously with stirring, until the water has evaporated.
The oxide powder obtained in this way contains practically no manganese metal and may be sintered or fused together with other metal oxides to form the desired ferrite. It is advantageous however to subject the dry product to a heat treatment at a temperature of about 150 C. for some hours.
The invention is illustrated by, but not limited to, the following Examples.
EXAMPLE 1 kg cf electrolytically prepared manganese metal are ground in a ball mill for twentyfour hours with 120 kg of steel balls until the metal has a mean particle size of about 3 microns. The manganese powder thus obtained is placed in a trough shaped container, about 300 litres of distilled water added and the whole heated on a hlating plate to a temperature of about 100 C. The mixture of manganese and water is stirred at this temperature until the material has been oxidised and is free from water. A brown, very fine, active manganese oxide is formed having the composition MnO3.
EXAMPLE 2 kg of electrolytically prepared manganese metal are ground in a ball mill with 120 kg of st.el balls and about 50 litres of distilled water for ten hours, the aqueous ground product being transferred to a flat, trough shaped container and heated to temperatures of about 100 C. with stirring. After all of the water has been evaporated, the whole is mixed with about 100 litres of distilled water and again evaporated to dryness. The temperature is then raised to about 150 C. and the material is kept at this temperature for about another five hours. A dark brown, very fine, active manganese oxide is obtained which has the composition Mn.O..
