To avoid increasing costs of landfill disposal, it has become increasingly important for U.S. foundries to identify beneficial reuses for the 8 to 12 million tons of waste foundry sand (WFS) generated annually. A major drawback to the reuse of some WFSs as a soil amendment is their high soil strength, under dry conditions, where root growth may be limited. Fifteen WFSs were analyzed for strengt...

A class of heterogeneous catalysts based on commercial bentonite from natural origin, containing at least 80 wt% of montmorillonite clay, was designed to transform selectively and under mild conditions toxic organosulfur and organophosphorus chemical warfare agents into non-noxious products with a reduced impact on health and environment. The bentonite from the natural origin was modified by in...

The adverse effect of mineral dust on general health level of the population has been widely studied lately. The research interest has been mainly focused on the respiratory function of coal miners and workers exposed to silica and asbestos containing dust [1-3] because a significant increase in COPD independent of smoking has been observed [4-5]. Among the materials considered hazardous for wo...

Three trials were conducted with recently weaned pigs (n = 198) to determine the effects of feeding different types of clay in conjunction with aflatoxin-contaminated diets. In Trial 1, pigs (n = 54; trial length 4 wk) were assigned to either an uncontaminated treatment (NC), 800 ppb of aflatoxin from contaminated corn (AC), or AC with one of four clays. In Trial 2 (n = 81; trial length 5 wk), ...

The design of clay plugs used for sealing access galleries to a radioactive waste repository built with concrete structures in a deep clayey formation must take into consideration their chemical evolution over time. Diffusion of an alkaline plume from concrete into bentonite was therefore modeled over a 100,000-year period with the PHREEQC geochemical code in order to determine, as a function o...

A Permian bentonite deposit at Melo, Uruguay is composed of a calcite-cemented sandstone containing clay pseudomorphs of glass shards (0-0.50 m) overlying a pink massive clay deposit (0.50-2.10 m). The massive bed is composed of two layers containing quartz and smectite or pure smectite respectively. The smectite is remarkably homogeneous throughout the profile: it is a complex mixed layer comp...

Clay minerals have previously been used to mitigate algal blooms because of their ability to flocculate algal cells or remove nutrients, but also offer considerable potential to remove ichthyotoxins. When a barramundi farm in tropical Australia suffered substantial fish mortalities due to a bloom of the ichthyotoxic haptophyte Prymnesium parvum, the farm manager decided to manipulate pond water...

electrochemically generated iron can remove most contaminants present in water and wast water, by precipitation, adsorption, electrostatic interaction, and complex formation (generally called electrocoagulation-ec). in the present paper, pretreatment of brackish water having high total hardness (th), alkalinity (a),  and cl¯ ions, is studied by application of a dc-electrical current ot the iron...

Cement bentonite interactions need to be studied since they will occur in deep geological repositories.They are specifically relevant in the clay host rock reference concept. The reactivity of a Mg-homoionicFEBEX bentonite was studied at 60 oC in contact with a young cement water characterized by the leachingof alkaline hydroxides (K/Na 4/1 –OH, pH = 13.5 at 25 oC) and with an e...

Silica sol, i.e., colloidal SiO2, may be used as a low-pH injection grout for very fine fractures in the construction of deep geological repositories for radioactive waste in Sweden and in Finland. If the bentonite barrier encounters SiO2-colloid particles under conditions favorable for aggregation, there is concern that it will modify the bentonite barrier at the bentonite/bedrock interface. I...