Furnace for melting inorganic salts

A furnace for melting inorganic salts, comprising:

• a container having a top and a bottom, comprising an internal cavity delimited by inner side walls of said container;
• at least one inlet area for solid inorganic salts at the top of said container;
• at least one outlet area for molten inorganic salts;
• and
• several heat exchanger tubes, through which combustion gases circulate, each heat exchanger tube comprising:
• a respective inlet section connected to an outer side wall of the container and in fluid communication with a respective burner;
• a respective spiral section extending from said inlet section and substantially disposed along the inner side walls of the container, the spiral section arranged on a substantially horizontal plane, said spiral section extending in a coil configuration having a decreasing diameter and defining an internal space of the spiral section;
• and
• a respective substantially vertical outlet section extending from said spiral section to a gas collector cavity located at the bottom of the container,
• wherein said gas collector cavity is positioned below and partitioned from said internal cavity and into which gases from said substantially vertical outlet section of each heat exchanger tube are evacuated;
• wherein the burners of the heat exchanger tubes are individually ignitable, and the respective spiral sections of the heat exchanger tubes are arranged at different heights defining different heating levels for the container, and
• wherein the respective internal spaces of the spiral sections are arranged in vertical registration relative to one another.