A corrosion resistant duplex stainless steel (ferritic austenitic alloy) is suitable for use in a plant for the production of urea. Uses of the corrosion resistant duplex stainless steel include in objects made of said duplex stainless steel, in methods for the production of urea, in a plant for the production of urea comprising one or more parts made from said duplex stainless steel, and in methods of modifying an existing plant for the production of urea. In one aspect, the composition consists of in weight % (wt %): C 0.010 to 0.015; S 0.08 to 0.23; Mn 1.0 to 1.05; Cr 29.07 to 29.92; Ni 5.76 to 7.17; Mo 3.0 to 4.0; W max 2.55; N 0.3 to 0.35; Cu max 0.01; S max 0.008; P max 0.008; at least one of Ti, Nb, Hf, Ca, Ba, V, and B max 0.5 total; balance Fe and unavoidable occurring impurities.

A release apparatus for receiving an ocean alkalinity product from an Ocean Alkalinity Enhancement (OAE) system (or other alkalinity source), and for releasing the alkalinity into an ocean at a maximum safe delivery rate to facilitate atmospheric CO.sub.2 reduction and mitigate ocean acidification. The release apparatus includes a diffuser having a plenum chamber defining exit ports, a flow control mechanism that controls delivery of the ocean alkalinity product through the exit port(s) into an outfall region (i.e., an ocean region surrounding the diffuser), sensors for measuring seawater parameters in the outfall region, and a controller configured to control an operating (actuation) state of the flow control device (e.g., by way of generating and transmitting a flow control signal) in accordance with the measured seawater parameters. The plenum chamber is anchored at an outfall location and is maintained at a constant depth with the exit ports aimed toward the ocean surface.

System and method for producing steel is provided that efficiently reduce carbon dioxide emissions. A steel production system includes: a first gas generating section configured to obtain a first gas by converting carbon monoxide, to carbon dioxide, in a gas containing the carbon dioxide and carbon monoxide; a reducing gas supply section 3 configured to supply a reducing gas containing a reducing substance to reduce a reducing agent, the reducing agent containing metal oxide to reduce carbon dioxide and being oxidized by contact with the carbon dioxide; and a reaction section 4 including a plurality of reactors 4a and 4b, respectively connected to at least one of the first gas generating section and the reducing gas supply section 3, and the reducing agent arranged in the reactors 4a and 4b, the reaction section being capable of switching between the first gas and the reducing gas to be supplied to each of the reactors 4a and 4b, wherein a second gas is configured to be supplied to a blast furnace, the second gas being obtained by contacting the first gas supplied to the reactors 4a and 4b with the reducing agent to convert the carbon dioxide to carbon monoxide and the second gas having the carbon monoxide as a main component.

An apparatus for direct reduction of iron ore in a solid state including a pre-heating furnace for pre-heating iron ore fragments and biomass in briquettes of these materials to a temperature in the range of 400-900 C.; and a reduction assembly for briquettes from the pre-heating furnace. The reduction assembly includes a reaction chamber, a source of electromagnetic energy in the form of microwave energy, a wave guide for transferring microwave energy to the chamber for heating and reducing iron ore in briquettes from the pre-heating furnace, with biomass acting as a reductant, a source of an inert gas, pipework for supplying the inert gas to the chamber to maintain the chamber under anoxic conditions, and an outlet for discharging an offgas and any retained particulates that are generated in the chamber.

A method for operating a smelting furnace installation, in particular a blast furnace installation, the method including the following steps: feeding coke, iron oxide containing material and if required fluxing agents to the top of the smelting furnace; injecting a first reducing gas containing hydrogen at a tuyere level of the smelting furnace at a temperature above 1600 C.; and injecting a second reducing gas at a lower shaft level of the smelting furnace.

The coke is fed at a lump coke rate below 220 kg/t HM, and the density of the first reducing gas is below 0.80 kg/Nm.sup.3.

The present invention pertains to the field of steel smelting, specifically to a method for steel production in a blast furnace and a converter based on carbon cycling. The method comprises the following steps: 1. Smelting iron in a blast furnace to obtain molten iron; 2. Introducing the aforementioned molten iron into a converter and carrying out steel refining within the converter to obtain molten steel and untreated converter gas; 3. Subjecting the untreated converter gas to pressurisation, deoxygenation, dehydration, and decarbonisation treatments to obtain synthesis gas and treated converter gas; 4. Recycling the treated converter gas back into the blast furnace to regulate the ratio of reductive gases within the furnace atmosphere.

Beneficial Effects: The method enables the cyclic utilisation of converter gas. By decarbonising the converter gas and recycling it back into the blast furnace, the content of reductive gases in the furnace atmosphere is enhanced. This promotes indirect reduction within the blast furnace while decreasing direct reduction, thereby reducing the consumption of carbonaceous fuel during the blast furnace iron smelting process and effectively lowering CO2 emissions.