Improved processes and systems are disclosed for producing renewable hydrogen suitable for reducing metal ores, as well as for producing activated carbon. Some variations provide a process comprising: pyrolyzing biomass to generate a biogenic reagent comprising carbon and a pyrolysis off-gas; converting the pyrolysis off-gas to additional reducing gas and/or heat; reacting at least some of the biogenic reagent with a reactant to generate a reducing gas; and chemically reducing a metal oxide in the presence of the reducing gas. Some variations provide a process for producing renewable hydrogen by biomass pyrolysis to generate a biogenic reagent, conversion of the biogenic reagent to a reducing gas, and separation and recovery of hydrogen from the reducing gas. A reducing-gas composition for reducing a metal oxide is provided, comprising renewable hydrogen according to a hydrogen-isotope analysis. Reacted biogenic reagent may also be recovered as an activated carbon product. Many variations are disclosed.

A method and an apparatus for recycling a significant amount of heat within a linear hearth furnace by means of an endless conveyor that transports briquettes through the furnace from an inlet (briquette feed) end to an outlet (DRI discharge) end and then returns to the inlet end and transfers a significant amount of heat from the outlet end to the inlet end of the furnace.

A method for producing briquettes from pellet fines, DRI sludge, DRI fines and dust from DRI dedusting systems and, in this way, reincorporating same into steel production processes, thereby contributing to the re-use of the by-products of these processes, as well as minimizing the stocks of these types of materials and, consequently, helping to improve the environment. The invention comprises: grinding and sieving the pellet fines and the DRI sludge; sieving the DRI fines; storing the dust from DRI dedusting systems; briquetting with roller presses, using liquid sodium silicate and bentonite or composite Portland cement as binders; sieving the briquettes; shredding the edges and waste of the fresh briquettes; and curing in order to improve the physical properties thereof, such as strength. Once cured, the fresh briquette can be stored or sent directly to direct-reduced iron production processes for use as part of the feedstock for reduction ovens or reactors.

The present invention concerns the use of a magnesium-including compound as binder for producing metallic ore fluxed pellets, in particular iron ore fluxed pellets, said magnesium-including compound comprising semi-hydrated dolime fitting the general formula aCa(OH).sub.2.Math.bMg(OH).sub.2.Math.cMgO, a, b, and c being weight fractions wherein the weight fraction b of Mg(OH).sub.2 is between 0.5 and 19.5 % by weight with respect to the total weight of said semi-hydrated dolime.

A method of operating a pelletizing plant for additional treatment of iron making, steelmaking and pellet plant residues, the plant including an indurating furnace in which green pellets are charged and fired to produce hard pellets, where the method includes: preparing iron ore green pellets; and charging and firing said green pellets in an indurating furnace, such that agglomerates of by-products are charged and fired with the green pellets in the indurating furnace, thereby producing hardened pellets and hardened agglomerates of by-products; a pelletizing plant is also presented including a pelletizing section, an indurating furnace, an agglomerating section for producing agglomerates of by-products, where a feeding arrangement is configured to charge agglomerates of by-products into said indurating furnace, together with the green pellets.

A method for producing iron ore pellets for operation of a blast furnace, where the iron ore pellets have a CaO/SiO.sub.2 mass ratio greater than or equal to 0.8 and a MgO/SiO.sub.2 mass ratio greater than or equal to 0.4, the method including balling green pellets by adding water to an iron ore material and dolomite and firing the green pellets. The dolomite is in a miniaturized state in a structure of the green pellets.

Provided is a method for producing a pellet capable of suppressing heat shock-induced crack occurrence, when nickel oxide ores are made into pellets and placed in a reducing furnace in a smelting process. In the method for producing a pellet from a nickel oxide ore, a nickel oxide ore, a binder and a carbonaceous reducing agent are mixed, the mixture is made into a lump, and then the resulting lump is subjected to a preheat treatment at a temperature of 350 C. to 600 C. In this preheat treatment, the lump more preferably undergoes the preheat treatment at a temperature of 400 C. to 550 C.

A method for charging pallet cars of a traveling grate for the thermal treatment of bulk material includes in a first step a first layer is applied as a hearth layer on a grate surface of the pallet car. In at least one second step a second layer at the same time or successively is applied as a side layer on two opposed side walls of the pallet car and a third layer is applied as green pellet layer between the side layers and on the hearth layer. The pellets used for the grate and the side layer differ in terms of their diameter and size distribution.

An induration machine includes a travelling grate for transporting bulk material along a transport direction from a heating zone for heating and/or drying the material to a cooling zone for cooling the material by cooling gas. The machine includes a hood disposed over the travelling grate having a first hood section in the heating zone and a second hood section in the cooling zone; and two recuperation ducts for guiding used cooling gas from the second hood section to the first hood section. The recuperation ducts are disposed on opposite sides of the hood, are laterally offset with respect to the hood, and are connected to the second hood section by a V-shaped gas collector duct. Each recuperation duct is connected to the first hood section by at least one gas supply duct and has at least one dust purge opening disposed in the lowermost part of the recuperation duct for purging dust from the recuperation duct.

A method for charging pallet cars of a traveling grate for the thermal treatment of bulk material includes in a first step a first layer is applied as a hearth layer on a grate surface of the pallet car. In at least one second step a second layer at the same time or successively is applied as a side layer on two opposed side walls of the pallet car and a third layer is applied as green pellet layer between the side layers and on the hearth layer. The pellets used for the grate and the side layer differ in terms of their diameter and size distribution.