LEACH ABILITY

After curing, the Unconfined Compressive Strength (UCS) of the samples was measured by using a penetrometer. The reagent ratio that resulted in the desired UCS (1.5-2.5 tons/ft ) was utilized for further leach-ability testing. 

Venditti, D., Durecu, S., and Berthelin, J. (2000a). A multidisciplinary approach to assess history, environmental risks, and remediation feasibility of soils contaminated by metallurgical activities. Part A Chemical and physical properties of metals and leaching ability. Arch. Environ. Contam. Toxicol. 38, 411-420. 

A study of the leaching ability of metals from plastics is important particularly where children s toys, foods and pharmaceuticals are concerned. A potential plastic to be used for any of these products must be analysed for total and leaching metal content by contacting the plastics with a stimulant similar to the product. Such plastics are strictly monitored and are rejected if a trace concentration of one or more listed toxic elements is detected. 

Quartz was also leached for 1 hr. at 250 C with 2.0 M solutions of either sodium hydroxide or sodium bicarbonate. In each case 2.0 g. of quartz was leached with 120 ml. of solution. Most of the quartz (99.5%) was converted to soluble sodium silicates and extracted by the hot sodium hydroxide solution. On the other hand, only 10% of the quartz was extracted by the sodium bicarbonate solution, and the residue appeared to be entirely quartz. These values were noticeably different from the 58% extracted by 1.0 M sodium carbonate under similar conditions. Therefore, these solutions were not equivalent in leaching ability even though each provided the same number of moles of sodium. None of the residues remaining after leaching quartz with any of the alkalis were acid-soluble. 

Oiled debris, beach material, and sorbents are sometimes disposed of at landfill sites. Legislation requires that this material not contain free oil that could migrate from the site and contaminate groundwater. Some governments have standard leach-ability test procedures that determine whether the material will release oil. Several stabilization processes have been developed to ensure that free oil does not contaminate soil or groundwater. One process uses quick lime (calcium oxide) to form a cement-like material, which can be used on roads as a dust-inhibitor. Another form of disposal is to process liquid oil in a bioreactor and thus attempt to break it down. This is usually not successful because of the many slowly degraded components in some oils. 

Trace metal constituents in CKD are generally found in concentrations <0.05% by weight. Because some of these constituents are potentially toxic at low concentrations, it is important to assess their levels (and mobihty or leach-ability) in CKD before considering its use. 

Notwithstanding this study, it is still possible that a coating with good leaching abilities serves well as a primer layer under a topcoat with good barrier properties. In case of damage in the coating, the inhibitors would only leach near the scratch and supply the inhibitor reliably when it is needed. 

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