Plant and method for producing decarbonized oxide or hydroxide using carbonate and electric power

A plant for producing decarbonized oxide or hydroxide, comprising an electric calciner, a contactor, a pH correction apparatus, and a dosing device, wherein:

• the electric calciner is configured to receive at the inlet a flow of carbonate, electric power and to release at the outlet at least one flow of carbonic gas at high temperature and at least one flow of oxide;
• the flow of oxide is adapted to provide a flow of buffering substance;
• the contactor is adapted to receive at the inlet the flow of carbonic gas released by the electric calciner, a flow of carbonate, a flow of water,
• the contactor is adapted to make the carbonate react with water and the CO2 present in the carbonic gas according to the following reactions:
• CO2(aq)+H2O(l)H2CO3(aq)H(aq)++HCO3(aq)− and
• CaCO3+CO2+H2O→Ca(HCO3)2(aq)
• wherein Ca can be substituted with Mg if present in the carbonate, and to release at the outlet at least one flow of ionic mixture;
• the contactor is configured for releasing non-soluble gases;
• the pH correction apparatus (is configured to receive at the inlet at least one flow of buffering substance and the flow of ionic mixture, is adapted to make the ionic mixture react with the buffering substance according to the following reactions:
• CaO+H2O+2CO2→Ca(HCO3)2(aq) or
• Ca(OH)2(aq)+2CO2→Ca(HCO3)2(aq)
• and to release at the outlet a flow of buffered ionic mixture;
• and
• the dosing device is configured to receive, at the inlet, a flow of buffering substance deriving from the electric calciner and to release at the outlet a predetermined quantity of buffering substance to feed the pH correction apparatus and possibly a quantity of buffering substance available for use.

A decarbonized calcination method comprising the steps of:

• providing an electric calciner,
• feeding the electric calciner with electric power and a flow of carbonate in order to obtain the calcination of the carbonate according to the reaction:
• CaCO3→CaO+CO2
• wherein Ca can be substituted with Mg if present in the carbonate;
• releasing at the outlet of the electric calciner a flow of carbonic gas at high temperature and a flow of oxide;
• conveying the flow of carbonic gas;
• conveying the flow of oxide;
• from the flow of oxide obtaining a flow of buffering substance;
• providing a contactor;
• feeding the contactor with the flow of carbonic gas produced by the electric calciner and a predetermined flow of water in order to obtain a flow of ionic mixture through the reaction:
• CO2(aq)+H2O(l)H2CO3(aq)H2(aq)++HCO3(aq)−;
• releasing the flow of ionic mixture at the outlet of the contactor;
• conveying the ionic mixture;
• providing a dosing device;
• feeding the flow of buffering substance to the dosing device;
• releasing a predetermined flow of buffering substance at the outlet of the dosing device;
• conveying the flow of buffering substance;
• providing a pH correction apparatus;
• feeding the pH correction apparatus with the flow of ionic mixture and with the predetermined flow of buffering substance so that the reactions take place:
• CaO+H2O+2CO2→Ca(HCO3)2(aq) or
• Ca(OH)2(aq)+2CO2→Ca(HCO3)2(aq);
• releasing the flow of buffered ionic mixture at the outlet of the pH correction apparatus;
• and
• placing the flow of buffered ionic mixture into the sea.