Method and system for producing direct reduced metal material, comprising the steps: a) charging metal material to be reduced into a furnace space (120); b) evacuating an existing atmosphere from the furnace space to achieve a gas pressure of less than 1 bar therein, c) providing heat and hydrogen gas into the furnace space, so that heated hydrogen gas heats the charged metal material to a temperature high enough so that metal oxides present in the metal material are reduced, in turn causing water vapour to be formed, which hydrogen gas provision is performed so that a pressure of more than 1 bar builds up inside the furnace space; and d) before evacuating the built up overpressure, condensing and collecting the water vapour formed in step c in a condenser (160) below the charged metal material. The invention is characterised in that it further comprises the step e) before evacuating the build up overpressure, providing a carbon-containing gas to the furnace space, so that the heated and reduced metal material is carburized by said carbon-containing gas.

A process for the production of direct reduced iron (DRI), with or without carbon, using hydrogen, where the hydrogen is produced utilizing water generated internally from the process. The process is characterized by containing either one or two gas loops, one for affecting the reduction of the oxide and another for affecting the carburization of the DRI. The primary loop responsible for reduction recirculates used gas from the shaft furnace in a loop including a dry dedusting step, an oxygen removal step to generate the hydrogen, and a connection to the shaft furnace for reduction. In the absence of a second loop, this loop, in conjunction with natural gas addition, can be used to deposit carbon. A secondary carburizing loop installed downstream of the shaft furnace can more finely control carbon addition. This loop includes a reactor vessel, a dedusting step, and a gas separation unit.

A process for the production of direct reduced iron (DRI), with or without carbon, using hydrogen, where the hydrogen is produced utilizing water generated internally from the process. The process is characterized by containing either one or two gas loops, one for affecting the reduction of the oxide and another for affecting the carburization of the DRI. The primary loop responsible for reduction recirculates used gas from the shaft furnace in a loop including a dry dedusting step, an oxygen removal step to generate the hydrogen, and a connection to the shaft furnace for reduction. In the absence of a second loop, this loop, in conjunction with natural gas addition, can be used to deposit carbon. A secondary carburizing loop installed downstream of the shaft furnace can more finely control carbon addition. This loop includes a reactor vessel, a dedusting step, and a gas separation unit.

A process for the production of sponge iron and a system for the production of sponge iron. The process includes the steps of: producing electrolytic hydrogen and oxygen by electrolysis of water; producing methanol by reacting the electrolytic hydrogen with carbon dioxide; storing the methanol; reforming the methanol using water and/or oxygen to provide carbon dioxide and released hydrogen; providing the released hydrogen as a component portion of a reducing gas to a direct reduction shaft; and reducing iron ore in the direct reduction shaft using the reducing gas to produce the sponge iron.

Method for producing direct reduced metal material, comprising the steps: a) charging metal material to be reduced into a furnace space (120); b) evacuating an existing atmosphere from the furnace space (120) so as to achieve an underpressure inside the furnace space (120); c) providing, in a main heating step, heat and hydrogen gas to the furnace space (120), so that heated hydrogen gas heats the charged metal material to a temperature high enough so that metal oxides present in the metal material are reduced, in turn causing water vapour to be formed; and d) condensing and collecting the water vapour formed in step c in a condenser (160) below the charged metal material, characterised in that steps c and d are performed at least until a hydrogen atmosphere overpressure has been reached inside the furnace space (120), and in that no hydrogen gas is evacuated from the furnace space (120) until said overpressure has been reached. The invention also relates to a system.

The present invention concerns a process for producing calcium carbonate from a calcium-containing alkaline slag material, the process containing the steps of extracting the alkaline slag material in a series of extraction steps, including at least 2 extraction steps, using extraction solvent(s) containing salt in an aqueous solution, whereby a calcium-containing filtrate and a residual slag is formed in each extraction step, separating the residual slag from the filtrate after each extraction step, carrying each residual slag to the following extraction in the series of extractions, to be used as raw material in said following extraction, and discarding the residual slag separated from the last extraction, carrying each filtrate to the previous extraction in the series of extractions, to be used as extraction solvent in said previous extraction, and carrying the first filtrate, separated from the first extraction step, to a carbonating step, carbonating calcium as calcium carbonate from the first filtrate, the first filtrate also used as the carbonation solvent, and using a carbonation gas, whereby calcium carbonate precipitates, separating and recovering the calcium carbonate from the remaining carbonation solvent, and recycling the remaining carbonation solvent to the last extraction step in the series of extraction steps, to be used as extraction solvent.

Method for producing direct reduced metal material, comprising the steps: a) charging metal material to be reduced into a furnace space (120); b) evacuating an existing atmosphere from the furnace space (120) so as to achieve an underpressure inside the furnace space (120); c) providing, in a main heating step, heat and hydrogen gas to the furnace space (120), so that heated hydrogen gas heats the charged metal material to a temperature high enough so that metal oxides present in the metal material are reduced, in turn causing water vapour to be formed; and d) condensing and collecting the water vapour formed in step c in a condenser (160) below the charged metal material; The invention is characterised in that said hydrogen gas in step c is provided without recirculation of the hydrogen gas, and in that the method further comprises the subse 15 quently performed step of removing the reduced metal material from the furnace space (120), and storing and/or transporting the reduced metal material under an inert atmosphere.

A blast furnace for ironmaking production wherein iron ore is at least partly reduced by a reducing gas which is injected in the stack of the blast furnace. The blast furnace includes an external and an internal wall, having a thickness T.sub.int, in contact with matters charged into the blast furnace. The thickness T.sub.int of the internal wall is substantially constant above and below the injection area of a reducing gas.

Method for producing direct reduced metal material, comprising the steps: a) charging metal material to be reduced into a first furnace space (120) of a first furnace (220); b) evacuating an existing atmosphere from the first furnace space (120) so as to achieve an underpressure; c) providing, in a main heating step, heat and first hydrogen gas to the first furnace space (120), so that metal oxides present in the metal material are reduced, in turn causing water vapour to be formed; and d) condensing and collecting the water vapour formed in step c in a condenser (160) below the charged metal material. The first hydrogen gas in step c is provided without recirculation of the first hydrogen gas, the method further comprises a subsequently performed charged material cooling step, in which thermal energy from the charged material is absorbed by said first hydrogen gas, and in which thermal energy, by heat exchange, is transferred from said first hydrogen gas to second hydrogen gas to be used in a second furnace (210) for producing direct reduced metal material. The invention also relates to a system.

A process for the production of direct reduced iron (DRI), with or without carbon, using hydrogen, where the hydrogen is produced utilizing water generated internally from the process. The process is characterized by containing either one or two gas loops, one for affecting the reduction of the oxide and another for affecting the carburization of the DRI. The primary loop responsible for reduction recirculates used gas from the shaft furnace in a loop including a dry dedusting step, an oxygen removal step to generate the hydrogen, and a connection to the shaft furnace for reduction. In the absence of a second loop, this loop, in conjunction with natural gas addition, can be used to deposit carbon. A secondary carburizing loop installed downstream of the shaft furnace can more finely control carbon addition. This loop includes a reactor vessel, a dedusting step, and a gas separation unit.