Evaluating the volatilization behavior of PAHs in oil-based residues from drilling cuttings of different thicknesses based on the C-history method

Drilling cuttings, the primary byproduct generated from the exploration and mining of shale gas, are potentially hazardous types of waste that seriously deplete land resources and pose environmental safety problems. In this paper, oil-based drilling debris is used as a typical porous medium phase solid waste, and the law and characteristics of unsteady diffusion and release of PAHs are studied under the specific situation of oil-based drilling debris with different thicknesses as the "source". The results showed that(1) Thickness has a greater influence on the diffusion and release law of PAHs from oil-based drilling cuttings residues, the diffusion release of PAHs increases with the increase of sample thickness. (2) The thickness of the porous media source is the main influencing factor of the PAHs diffusion and release diffusion related parameters. The higher the thickness, the diffusion coefficient Dm increases with the increase in thickness. The distribution coefficient K and the initial diffusible release concentration Cm0 change in a similar manner, and both increase with the thickness.

Studies on volatilization behavior of RuO4 from nitric acid medium

This paper reports volatilization behavior of RuO4 from nitric acid medium using UV–Vis spectroscopy. Ruthenium (III) solution was oxidized to Ru (VIII) using potassium metaperiodate. The absorption peak of RuO4 at 385 nm was used to measure Ru(VIII) concentration in solution. The volatilization kinetics has been studied at different temperature and used to derive rate constant and activation energy values. Almost 82% Ruthenium (VIII) has been volatilized from nitric acid medium at 70 °C whereas it is only 15% at 25 °C. Effect of different parameters like temperature, potassium metaperiodate concentration and nitric acid concentration on volatilization has been studied in depth and reported in this paper.

Volatilization Behavior of Manganese from Molten Steel with Different Alloying Methods in Vacuum

The volatilization loss of manganese during the vacuum smelting process is one of the key factors that determines the manufacturing cost and quality of manganese steel. In this study, the laboratory experiments and thermodynamic calculations were performed to investigate volatilization behavior of manganese from molten steels with different alloying methods in vacuum process. Based on the thermodynamic analysis, with the increase of manganese content, the partial vapor pressure of the manganese component increased, resulting in manganese being easily volatilized from molten steel. The carbon content in the steel shows an evident influence on partial vapor pressure of manganese component, and a higher carbon content in steel leads to a lower partial vapor pressure of manganese, but it not influenced by the silicon content. Compared with the alloying method of high carbon ferromanganese, the volatilization loss of manganese in the alloying method of silicon manganese presents faster decay, agreeing well with the thermodynamic analysis. Besides, the volatile fraction generated in the alloying method of high-carbon ferromanganese is composed of a large amount of MnO nanorods with a lateral length approximately 500 nm and a small number of Mn3O4/Mn nanoparticles with a diameter less than 500 nm. Additionally, the volatile fraction generated in the alloying method of silicon manganese shows Mn3O4 nanoparticles as the main phase. It can be inferred that the existence of the manganese oxide phase is attributed to the high chemical activity of nanoscale particles within air.

Low Temperature Sequential Melting and Anion Retention in Simplified Low Activity Waste

ABSTRACTThis study seeks to understand the low temperature reactions of the salt phase that occur during the vitrification of Hanford Low Activity Waste (LAW). Salts (such as nitrates, sulfates, carbonates, halides, etc.) play a key role in these low temperature reactions as they sequentially melt, decompose, and volatilize during batch-to-glass conversion. To further understand these complex processes, simplified LAW melts containing oxyanion salts (sodium salts of carbonate, sulfate, and/or nitrate) and early melting glass formers (boric acid) have been evaluated using thermal analysis, infrared absorption spectroscopy, and X-ray diffraction. Results from this study indicate that the volatilization behavior of particular salts is influenced by the presence or absence of other salts. NaNO3 volatilization is decreased by the presence of Na2SO4. The addition of either Na2SO4 or NaNO3 to the system may enhance the volatilization of Na2CO3. In all cases, Na2SO4 was retained after melting and was often found to be in two different crystalline phases upon quenching.