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Oxidation of pyrite in clay formations in contact with concrete – this produces sulfuric acid which reacts with concrete. Bacterial activity in sewers – anaerobic sulfate reduction at work in the organic-rich sludges accumulated under water in the conduits produces hydrogen sulfide gas (H 2 S).
The hydrogen sulfide gas is biochemically oxidized in the presence of moisture to form sulfuric acid. The effect of sulfuric acid on concrete and steel surfaces exposed to severe wastewater environments can be devastating. [1] In the USA alone, corrosion causes sewer asset losses estimated at $14 billion per year. [2]
The sulfuric acid released by pyrite oxidation then reacts with portlandite (Ca(OH 2)) present in the hardened cement paste to give gypsum: H 2 SO 4 + Ca(OH) 2 → CaSO 4 · 2H 2 O. When concrete is carbonated by atmospheric carbon dioxide (CO 2), or if limestone aggregates are used in concrete, H 2 SO 4 reacts with calcite (CaCO
Concerns were expressed that this could in turn give rise to sulfuric acid, and thus accelerate damage to the concrete. The controversy itself, as well as its handling, continued for some years. In 2004 an aeration plant was installed to address the root cause in the reservoir, as had been suggested 18 years earlier. [4] Gilgel Gibe III Dam in ...
Sulfur concrete has a low porosity and is a poorly permeable material. Its low hydraulic conductivity slows down water ingress in its low porosity matrix and so decreases the transport of harmful chemical species, such as chloride (pitting corrosion), towards the steel reinforcements (physical protection of steel as long as no microcracks develop in the sulfur concrete matrix).
While most modern automotive batteries are sealed, and do not leak battery acid when properly stored and maintained, [513] the sulfuric acid in them can leak out and stain, etch, or corrode concrete floors if their cases crack or tip over or their vent-holes are breached by floods. [514]
Chemical safety includes all safety policies, procedures and practices designed to minimize the risk of exposure to potentially hazardous chemicals. This includes the risks of exposure to persons handling the chemicals, to the surrounding environment, and to the communities and ecosystems within that environment. [ 1 ]
Sulfuric acid is a colorless oily liquid, and has a vapor pressure of <0.001 mmHg at 25 °C and 1 mmHg at 145.8 °C, [16] and 98% sulfuric acid has a vapor pressure of <1 mmHg at 40 °C. [ 17 ] In the solid state, sulfuric acid is a molecular solid that forms monoclinic crystals with nearly trigonal lattice parameters.