Manganese ferrites

Claim 1

A METHOD OF MAKING A FERRITE CONTAINING BIVALENT MANGANESE IONS WHICH COMPRISES PREPARING A MIXTURE OF OXIDES INCLUDING FERRIC OXIDE AND AN OXIDE OF MANGANESE HIGHER THAN MANGANOUS OXIDE, PASSING SAID MIXTURE THROUGH A FURNACE HAVING INITIALLY AN AIR ATMOSPHERE AND DIFERENT ZONES MAINTAINED AT TEMPERATURES CORRESPONDING TO THE HEATING AND COOLING TEMPERATURE CYCLE REQUIRED FOR MAKING THE SAID FERRITE, AND CONTROLLING THE ATMOSPHERE INSIDE SAID FURNACE BY MEANS OF AN OXIDIZABLE MATERIAL INTRODUCED INTO SAID FURNACE, TOGETHER WITH BUT NOT IN CONTACT WITH SAID MIXTURE, SAID OXIDIZABLE MATERIAL BEING SELECTED FROM THE GROUP CONSISTING OF 200 MESH ELECTRILYTIC IRON POWDER, 123 MESH ALUMINUM POWDER, 300 MESH ELECTROLYTIC MANGANESE POWDER, FINE CARBON POWDER, 150 MESH ALLOY POWDER COMPOSED OF 4% MO, 79% NI, 17%FE, AND 150 MESH ALLOY POWDER COMPOSED OF 2% MO, 81% NI, 17% FE, SAID IRON POWDER HAVING A WEGHT OF SUBSTANTIALLY 6% BY WEIGHT OF SAID MIXTURE, SAID ALUMINUM POWDER HAVING A WEIGHT OF SUBSTANTIALLY 2.93% BY WEIGHT OF SAID MIXTURE, SAID MANGANESE POWDER HAVING A WEIGHT OF SUBSTANTIALLY 8.9% BY WEIGHT OF SAID MIXTURE, SAID CARBON POWDER HAVING A WEIGHT OF SUBSTANTIALLY 1.92% BY WEIGHT OF SAID MIXTURE, AND SAID 150 MESH ALLOY POWDER HAVING A WEIGHT SUBSTANTIALLY 6.28% BY WEIGHT OF SAID MIXTURE, AND SAID HEATING AND COOLING TEMPERATURE CYCLE COMPRISES HEATING SAID MIXTURE UP TO 1250 DEGREE CENTIGRADE OVER A PERIOD OF FOUR HOURS, MAINTAINING THE 1250 DEGREE CENTIGRADE TEMPERATURE FOR A FURTHER PERIOD OF FOUR HOURS, AND COOLING TO ROOM TEMPERATURE OVER A PERIOD OF SIXTEEN HOURS.