Evaluation of Glass Coatings with Various Silica Content Corrosion in a 0.5 M HCl Water Solution

Two enamel coatings with a high and a low silica content were prepared on 35CrMo steels via vacuum firing. Their corrosion behavior in a 0.5 M HCl solution including corrosion kinetics, microstructures and electrochemistry performance were studied in comparison with uncoated steels. The results show that catastrophic corrosion occurred for uncoated steels while enamel coatings significantly decreased the corrosion rate. Enamel coatings with a high silica content exhibited the best corrosion resistance against hydrochloric acid due to their highly connected silicate network, which inhibited the leaching process of alkali metals in the acid solution. The corrosion inhibition efficiency for enamel containing a high silica content reached a maximum of 94.3%.

Co-Pyrolysis of Rice Husk and Chicken Manure

The increase in the production scale of chicken causes an increment in the produced manure. Chicken manure is considered an excellent soil amendment due to the high nitrogen and phosphorous content. However, the high production of manure exceeds the soil requirements. Rice husk is a by-product of rice production. Approximately one hundred forty million tons of rice husk is produced per year worldwide. There are several ways to manage rice husk such as animal bedding, direct combustion, or as a soil fertilizer. The husk's ashes are suitable for construction or as reinforcing material due to the high silica content. However, rice husk has a low volatile matter and high silica content, which makes processes like direct combustion inefficient. Thermochemical processes (such as pyrolysis and gasification) are effective ways to manage waste. The present study investigates the co-pyrolysis of chicken manure and rice husk. The experiments were conducted in a non-isothermal gravimetrical analyzer using nitrogen at a flowrate of 100 ml/min at three different heating rates (5, 10, and 15 °C/min). The degradation of individual biomass and biomass blends is investigated. The kinetic parameters are calculated using the Friedman method. Results show a positive synergetic effect for mixing ratios greater than 20% rice husk. The mixing ratio of 40% of rice husk manifested the best performance among all blends. This mixture showed the minimum energy of activation (90.2 kJ/mol). Also, the 40% rice husk mixing ratio showed maximum conversion when compared with chicken manure's conversion.

Survey on the chemical composition of several tropical wood species

Variability in the chemical composition of 614 species is described in a database containing measurements of wood polymers (cellulose, lignin and pentosan), as well as overall extraneous components (ethanol-benzene, or hot water extracts and ash, with a focus on silica content). These measurements were taken between 1945 and 1990 using the same standard protocol. In all, 1,194 trees belonging to 614 species, 358 genera and 89 families were measured. At species level, variability (quantified by the coefficient of variation) was rather high for density (27%), much lower for lignin and cellulose (14% and 10%) and much higher for ethanol/benzene extractives, hot water extractives and ash content (81%, 60% and 76%). Considering trees with at least five different specimens, and species with at least 10 different trees, it was possible to investigate within-tree and within-species variability. Large differences were found between trees of a given species for extraneous components, and more than one tree should be needed per species. For density, lignin, pentosan and cellulose, the distribution of values was nearly symmetrical, with mean values of 720 kg/m3 for density, 29.1% for lignin, 15.8% for pentosan, and 42.4% for cellulose. There were clear differences between species for lignin content. For extraneous components, the distribution was very dissymmetrical, with a minority of woods rich in this component composing the high value tail. A high value for any extraneous component, even in only one tree, is sufficient to classify the species in respect of that component. Siliceous woods identified by silica bodies in anatomy have a very high silica content and only those species deserve a silica study.