Efficient Dewatering of Slimes and Sludges with a Bubble Column Evaporator

The recalcitrant nightmare of de-watering slime/sludge is a major issue, for both industry and the environment. A simple process is developed that solves the problem. It uses a bubble column evaporator (BCE) with heated dry air. The model slime to illustrate the de-watering process was a concentrated dispersion of spherical 5 micron silica particles in pure water. Typical slime samples were de-watered in the range 20-35% colloid/water (w/w) using dry inlet gases pre-heated to temperatures of 150°C and 250°C. The BCE process was run at sub-boiling temperatures, with the column solution in the range, 43°C and 74°C, with those two inlet temperatures operating for de-watering the slime. A significant bonus is that the pure water vapour produced can be condensed and used as a source of high-quality water for reuse. The BCE process offers simplicity, resilience to slime feed quality, and a pure water biproduct. It also offers a continuous and controlled low-maintenance process. These are clear advantages in de-watering a wide variety of industrial slimes and sludges. In addition, the process involves the passage of a continuous flow of hot dry gases. This causes the dispersion to remain sufficiently fluid to allow easy transportation. However, once the hot gas flow ceased, the dispersion immediately solidified. The success of the bubble column process for dewatering and validation of the mechanism is even more enhanced if helium is used instead of air. It appears that hot helium atoms can disrupt water hydrogen-bonding in the liquid surrounding the hot bubbles and this enhances water vapour collection efficiency. The bubble method appears to offer more than significant advantages over other methods, such as hydrocyclone methods, which are often used to de-water mining wastes.

Spatiotemporal Symmetry and Trend Assessment of Ms≥7.0 Earthquakes in the Sichuan-Yunnan Region of China

Commensurability information, a butterfly diagram and a commensurability structure system were used to analyse the spatiotemporal symmetry and to assess the trends of Ms≥7.0 earthquakes in the Sichuan-Yunnan region of China. The results show that the next earthquake may occur in 2020 or 2021, as seismic signals are strong. Analysing the characteristics of epicentre spatial migration, there is a significant synchrony and symmetry between the latitudinal and longitudinal epicentre migrations. The symmetry axis is 30°N in latitude and 101.5°E in longitude. There is a northeast–southwest strike symmetry axis, and the next epicentre may migrate toward the southwest (i.e., south of 30°N and west of 101.5°E); the calculated strike symmetry axis is Y=3.5X-329. By grouping earthquake disaster events, the spatial migration pathways of the epicentres regularly exhibit jump-migration and sequential-migration. The migration distributions over the symmetry axis quadrants are ‘uniform-discrete’ and ‘concentrated-dispersion’.

Clear transparent cellulose nanopaper prepared from a concentrated dispersion by high-humidity drying

Optically transparent paper is fabricated from concentrated cellulose nanofiber dispersion by high-humidity drying.

Preparation and Properties of PTFE/SA Blend Membrane

Poly (tetrafluoroethylene) (PTFE)/Salt alginate (SA) flat membranes were prepared from a mixture of PTFE concentrated dispersion and Sodium alginate (NaAlg) aqueous solution. The chemical constitutions of the PTFE/SA membranes before and after sintering were investigated with FTIR. Meanwhile, TGA and contact angle to water were utilized to analyze the thermal stability and hydrophobic property. Moreover, effects of sintering conditions on the properties and morphologies of the membranes were also investigated. Results showed that SA was decomposed in the sintering process, and the membranes maintained excellent thermal stability and strong hydrophobicity. In addition, it was beneficial for the membranes to obtain high air flux by short sintering time and the membranes had different surface morphologies by different cooling rates.