KR860001203A - Non-electrolytic Reduction Process of Rare Earth Oxides Using Calcium Metals - Google Patents

Abstract

Rare earth oxides can be reduced to rare earth metals by, a novel, high yield, metallothermic process. The oxides are dispersed in a suitable, molten, calcium chloride-based bath (44) along with calcium metal. The bath (44) is agitated and calcium metal reduces the rare earth oxides to rare earth metals. The metals collect in a discrete layer (43) in the reaction vessel (22).

Description

Non-electrolytic Reduction Process of Rare Earth Oxides Using Calcium Metals

As this is a public information case, the full text was not included.

1 is a cross-sectional side view of a device suitable for the process of reducing RE-oxides to RE metals according to the invention,

FIG. 2 is a process overview for calculating neodymium- eutectic alloy by reducing neodymium oxide (ND ₂ O ₃ ) together with calcium;

FIG. 3 is a graph showing the solubility of neodymium (Nd) metal produced from neodymium oxide (ND ₂ O ₃ ) as the CaCl ₂ concentration function in salt jade.

Explanation of main symbols in the drawings

8, 10, 12: clamshell heater, 15: thermocouple, 20: furnace well, 22: reactor, 24: stirrer, 28: variable speed motor, 36: coolant coil, 38: stainless steel baffle.

Claims (13)

To disperse the rare earth oxide (RE _n O _m ) with less volume than the salt bath in the salt bath whose main component is calcium chloride (CaCl ₂ ), add the stoichiometric excess of calcium metal more than the rare earth oxide and then stir, according to the following reaction formula An electroless reduction process of rare earth oxides, characterized in that the oxides are reduced to metals. RE _n O _m + m Ca → n RE + m CaO In the formula, RE means rare earth elements having valence of 2,3 or 4, 0 means oxygen, Ca means calcium, CaO means calcium oxide, n and m are oxidation states of rare earth elements The number determined by multiplying n by the valence of the rare earth element is determined to be equal to the number by which the oxygen atom is multiplied by m. The electroless reduction process according to claim 1, wherein the rare earth oxide is neodymium oxide (Nd ₂ O ₃ ). Nd ₂ O ₃ + 3Ca → 2Nd + CaO 2. The rare earth according to claim 1, wherein a molten salt bath is formed, and a predetermined amount of heat earth oxide and calcium (Ca) metal which is stoichiometrically excess than the rare earth oxide are added thereto, followed by stirring while maintaining the salt bath in a molten state. An electroless reduction process of rare earth oxides, characterized in that the oxides are reduced to rare earth metals. The process of claim 3, wherein the rare earth oxide is neodymium oxide (Nd ₂ O ₃ ). The method of claim 1, wherein a salt bath comprising at least 70 wt% or more of calcium chloride (CaCl ₂ ) is formed, and the salt bath is added with a predetermined amount of rare earth oxides and a stoichiometric excess of the rare earth oxides (Ca) metal. Next, while maintaining the salt bath in a molten state, stirring is continued until reduction is completed, and then left to stand to form a separation layer containing a rare earth metal in the salt bath. 6. The process of claim 5, wherein the rare earth oxide is a single rare earth oxide or a mixture of two or more rare earth oxides selected from the group consisting of lanthanum oxide, cerium oxide, praseodymium oxide and neodymium oxide. A molten salt bath according to claim 5, wherein a molten salt bath consisting of at least 70 wt% or more of calcium chloride (CaCl ₂ ) and the remaining wt% of sodium chloride (NaCl) is formed, wherein the volume of the neodymium oxide is 50% or less of the volume of the salt bath ( Nd ₂ 0 ₃ ) and calcium (Ca) metal which is more stoichiometric than the neodymium oxide is added, and then stirring is performed until the neodymium oxide is sufficiently reduced to neodymium (Nd) while maintaining the salt bath in a molten state. The process of electroless reduction of rare earth oxides (neodymium oxide), characterized by forming a separation layer containing no neodymium oxide but reduced neodymium metal in a salt bath while leaving them in a molten state. The calcium metal of claim 1 which forms a salt bath consisting of at least 70 wt% or more of calcium chloride and the remaining wt of sodium chloride, wherein the volume is rare earth oxide and a stoichiometric excess of said rare earth oxide. After the addition of the mixture, the salt layer was kept in a molten state, stirred until the rare earth oxide was sufficiently reduced to the rare earth metal, and the resultant components were left still in a molten state to leave the separation layer containing the rare earth metal reduced in the salt bath. An electroless reduction process of rare earth oxides, characterized in that the formation. The method of claim 1, wherein a molten salt bath consisting of at least 70 wt% or more of calcium chloride and up to 30 wt% or less of sodium chloride is formed, wherein a predetermined amount of rare earth oxides and a calcium (Ca) metal that is stoichiometrically greater than the rare earth oxides are formed. Then, while stirring while keeping the salt bath in a molten state, a predetermined amount of non-rare earth metal is added to form a rare earth metal / non-rare earth metal alloy having a melting point lower than that of the rare earth metal itself, and then the stirring is stopped and left to stand. An electroless reduction process of rare earth oxides, characterized in that the rare earth metal / non-rare earth metal alloys are collected and recovered in separate layers in a salt bath. 10. The process of claim 9, wherein the rare earth oxide is a single rare earth oxide or a mixture of two or more rare earth oxides selected from the group consisting of lanthanum oxide, cerium oxide, praseodymium oxide and neodymium oxide. 10. The process of claim 9, wherein the rare earth oxide is neodymium oxide. 10. The process of claim 9, wherein the non-rare earth metal is iron (Fe). 10. The process of claim 9, wherein the non-rare earth metal is zinc (Zn). ※ Note: The disclosure is based on the initial application.