Process for the recovery of high purity metallic sodium and the safe treatment of high calcium content sodium slag

A process for the preparation of high purity metallic sodium and the safe treatment of high calcium content sodium slag, the process comprises the following steps:

• (1) subjecting a liquid sodium obtained from an electrolysis to a supergravity separation to obtain a high purity metallic sodium and a high calcium content sodium slag;
• (2) subjecting said high calcium content sodium slag to at least one roasting process to obtain a roasting slag;
• (3) leaching said roasting slag with an alkaline liquor to produce sodium hydroxide solution and calcium hydroxide,
• wherein the liquid sodium contains Na in an amount of 95-99.9 wt % and Ca in an amount of 0.1-5 wt %, based on the total amount of the liquid sodium,
• wherein the sodium content of the high purity metallic sodium is 99.8 wt % or more,
• wherein the high calcium content sodium slag contains Na and Ca,
• wherein Na is contained in an amount of 50-75 wt % and Ca is contained in an amount of 25-50 wt %, based on the total amount of named high calcium content sodium slag,
• wherein the at least one roasting process includes an initial roasting stage, a stable roasting stage, and a finish roasting stage, and
• wherein the temperature of each roasting stage satisfies the relationship that the initial roasting stage temperature <stable roasting stage temperature <finish roasting stage temperature.