US2382909A

US2382909A - Manufacture of strontium oxide

Info

Publication number: US2382909A
Application number: US446432A
Authority: US
Inventors: Bank The First National
Original assignee: Individual
Current assignee: Individual
Priority date: 1942-06-10
Filing date: 1942-06-10
Publication date: 1945-08-14
Anticipated expiration: 1962-08-14

Description

14, "19%. J. B. MERGE, JR- 2933329909 MANUFACTURE OF STRONTIUM QXIDE Filed June 10, 1942 Jaws D; Y 431 f? se Patented Aug. 14, 1945 I James B: Pierce,- Jr.,' Charlestonfwfiyaq" First National Bank' of Tampa executor-f said 7 James B. Pierce, Jr., deceased i Application June 10, 1942, serial No. 446,432

1 Claim.

This invention relates to the production of strontium oxide and has for its particular objects the extremely expeditious and economical manufacture of a product which is highly per- Fig. 2 is a left end elevation of such furnace including the drive mechanism-therefor; and

Fig. 3 is a central vertical section taken on the line 33 of Fig. 1.

' Referring to the drawing and construction shown therein, the reference numeral I designates an oscillatory barrel or drum having circular rails or tracks 2 externally mounted thereon which are supported on idler rollers 3, 3' and a driving roller 4, having a stub shaft 4', said driving roller being driven by a belt 5 which is reeved over its stub shaft and over a driving pulley 6 carried by a drive shaft 1. The said furnace has opposed electrodes 8, 8' which extend axially into the drum through the respective ends thereof and a lateral charging aperture 9, normally closed but not hermetically sealed by a door Ill, admits of the introduction into the drum of a charge of material to be fired. I

In carrying out my improved method the barrel is partially filled, through the door thereof, with a charge comprising equimolecular weights of ashless carbon black and strontium carbonate, the latter being desirably prepared in the manner described in my prior Patent No. 1,782,830 of November 25, 1930. The door is then closed but not sealed in order to permit of the maintenance of an envelop of CO, at atmospheric pressure, over the charge during the firing thereof. The circuit through the electrodes 8, 8' is then closed and an arc sufficient to maintain a temperature of about 1200 C. is established therebetween. The furnace is constantly oscillated to-and-fro, through an arc of approximately 185, in order to promote the rapid evolution from the charge of the carbon monoxide gas generated by the reaction. When the reaction is completed, usually in about 2 hours, the furnace is allowed to cool and the resultant strontium oxide recovered.

Since the heat from the electric arc is internally supplied to the charge, it will be concentrated directly against the reacting mass and be far more efficient than if the same amount of heat input were supplied through the wall of a muflie furnace such as employed in the method disclosed in my aforesaid patent. Furthermore, there is.no known refractory that is capable of standing up for any substantial length of time if the same amount of heat in British thermal units at 1200 C., were indirectly applied through a muflie to the charge as is supplied to the charge when employing the electric arc in accordance with my invention, this being due to the high temperature drop in passing through the muffle as compared with the relatively low temperature drop between the arc and the charge, since in the latter case the heat developed by the arc has only to pass through the evolved carbon monoxide gas at atmospheric pressure.

But about one-sixth the time is required in my new process, where the heating of the charge is direct, as compared with my prior process employing a muffle furnace, because of the greater heat input of the electrodes employed and the absence of any partial pressure of any carbon dioxide over the reacting mass or charge such as is inevitably present in a muilie furnace due to the leakage or permeation through the wall of the mufiie of the combustion gases. Furthermore the practically complete absence of carbon dioxide within the furnace permits the reaction to proceed to completion at the same temperature with far greater rapidity than if there were any partial pressure of CO2 over the reacting mass. Likewise, the free escape through the closed but not completely sealed door of the carbon monoxide developed in the reaction, insures that the partial pressure of the C0 will not be above atmospheric pressure and thereby the velocity of the reaction is substantially increased. Also, as above stated, the oscillation of the furnace facilitates the rapid evolution of the gaseous carbon monoxide reaction product and as a consequence, the most effective heating of the charge can be realized and the velocity of the reaction is a maximum for the temperature employed.

The resultant strontium oxide product obtained in my process as above described is ideally adapted for the production of strontium peroxide the same being soft, flaky and remarkably permeable and consequently highly reactive to oxygen. In fact, at pressures not exceeding 800 lbs. per square inch at least of such oxide can be converted by oxidation into strontium peroxide.

While I preferably employ ashless carbon black as the reducing agent of the charge, other forms of substantially pure, finely divided free carbon may be substituted therefor such for example as finely powdered coke or ashless tar and the like.

The temperature employed is preferably 1200 C. but inany event it should be in excess of 1100 C. and sufficient to effect the approximately complete reduction of the strontium carbonate in the charge to strontium OXide.

Various modifications of the within described method of making strontium oxide within the scope of the claim may be made without departing from the spirit of my invention.

Having thus described my invention, what I claim is:

The method of making strontium oxide which comprises confining a charge consisting of substantially equimolecular weights of free carbon and strontium carbonate in a substantially closed chamber and therein subjecting the same to the heat of an electric arc of an intensity sufiicient to heat the charge to a calcining temperature, not less than 1100 C., while continually maintainingover the charge, during'the firing thereof, an envelope of nascent carbon monoxide at substantially atmospheric pressure and substantially free