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The role of coal in iron and steel metallurgy is analyzed through the routes for steel manufacturing, current levels of steel production, and forecasts for the future. Coal as an essential raw material in different metallurgical processes is discussed, emphasizing the functions of metallurgical coke in ironmaking via the blast furnace. The potential of biomass as an additive in cokemaking and as an injectant in a blast furnace to mitigate fossil CO2 emissions is also addressed.

Concerns about energy security, energy prices and climate change led scientific research towards sustainable solutions to fossil fuel as renewable energy sources coupled to hydrogen as energy vector and carbon capture and conversion technologies. Among the technologies investigated in the last decades, biomass gasification acquired great interest owing to the possibility to obtain low cost and CO2 negative emission hydrogen production from a large variety of everywhere available organic wastes. Upstream and downstream treatment were then studied in order to maximize hydrogen yield, reduce the content of organic and inorganic contaminants under the admissible levels for the technologies which are coupled with, capture, and convert carbon dioxide. However, studies which analyse a whole process made of all those technologies is still missing. In order to fill this lack, the present paper investigated the coexistence of Hydrothermal Carbonization (HTC), Sorption Enhance Gasification (SEG), Hot Gas Cleaning (HGC), and CO2 conversion by Dielectric Barrier Discharge (DBD) plasma reactor for H2 production from biomass waste by means of Aspen Plus software. The proposed model aimed to identify and optimise the performance of the plant by varying operating parameters (such as temperature, CaO/biomass ratio, separation efficiency, etc.). The carbon footprint of the global plant is 2.3 kg CO2/kg H2, lower than the latest limit value imposed by the European Commission to consider hydrogen as “clean”, that was set to 3 kg CO2/kg H2. The hydrogen yield referred to the whole plant is 250 gH2/kgBIOMASS.

This study investigates the suitability of different lignocellulosic sources, namely eucalyptus, apple bagasse, and out-of-use wood, for injection into blast furnaces (BFs). While wastes possess carbon potential, their high moisture renders them unsuitable for direct energy utilization. Additionally, the P and K impurities, particularly in apple bagasse, can pose operational and product quality challenges in BF. Thus, different thermochemical processes were performed to convert raw biomass into a more suitable carbon fuel. Low-temperature carbonization was selected for eucalyptus, yielding a biochar with properties closer to the low-rank coal. Hydrothermal carbonization was chosen for apple bagasse and out-of-use wood, resulting in hydrochars with enhanced fuel characteristics and fewer adverse inorganic species but still limiting the amount in binary PCI blends. Thermogravimetry evaluated the cause–effect relationships between coal and coal- and bio-based chars during co-pyrolysis, co-combustion and CO2-gasification. No synergistic effects for char formation were observed, while biochars benefited ignition and reactivity during combustion at the programmed temperature. From heat-flow data in combustion, the high calorific values of the chars were well predicted. The CO2-gasification profiles of in situ chars revealed that lignin-rich hydrochars exhibited higher reactivity and conversion than those with a higher carbohydrate content, making them more suitable for gasification applications.

Waste-derived hydrochars are presented for the first time as promising materials to reduce the consumption of natural resources and the carbon footprint of the cement industry, while eliminating waste and sequestering a high amount of carbon in civil infrastructures. Rice husk (RH) and stabilized organic waste from a mixed municipal waste mechanical-biological treatment plant (SOW) were subjected to hydrothermal carbonization at 200 °C for 2 h and the resulting hydrochars were thoroughly evaluated as cement substitutes in fresh and hardened mortars. Compared to the control, mortars with 1.25–5 wt% of cement replaced by hydrochar from stabilized organic fraction caused a decrease in compressive strength of about 50–60% at 28 days of curing, while flexural strength was diminished by about 38–47%. The use of rice husk-derived hydrochar led to a reduction of 32–47% in compressive strength and of 22–34% in flexural strength. With compressive and flexural strengths of 27–41 and 3.31–4.92 MPa, respectively, blended mortars (28 days) display good prospects for use in plastering, rendering, masonry, partition panels and low-load paving. On the other hand, substituting 5 wt% of cement by hydrochar decreases the thermal conductivity and increases electrical resistivity of the mortar by 25–30%, which enhances thermal insulation properties and potential durability. This approach opens a new avenue for large-scale application of biowaste hydrochars as secondary raw materials for sustainable construction.

Nowadays aquaculture provides animal protein of quality for human consumption, necessary to maintain the high world population, thus supporting fisheries production constrained by overexplotitation of fishing (FAO, 20222). However, it is important to produce it in a cost-effective and sustainable way. Since 2012, biochar is starting to be included in animal feed (Gerlach & Schmidt, 2012). Biochar is obtained by pyrolisis from organic waste in a low-to-no oxigen thermal process, reusing by-products from other industries (European Biochar Foundation - EBC 2012). This product has been shown to improve nutrien intake efficiensy, absorb toxin and generally improve animal health besides improving the quality of the effluent water (O'Toole et al., 2016, Toth and DU, 2016, Schmidht et el, 2019), making it a good candidate for its inclusion y aquafeeds. This study aims to test the putative improvement produced by the dietary inclusion of biochar in Senegalese sole, a species of great interest in Spain.