Oxidation Proof Silicate Surface Coating On Iron Sulfides

The present method induces an oxidation-proof ferric silicate coating on iron sulfide such as pyrite and marcasite. The method includes the steps of placing the pyrite to be treated in a reaction vessel and leaching the pyrite with a coating composition including water, an oxidizing agent and a silicate coating agent. Examples of oxidizing agents include hydrogen peroxide, sodium hypochlorite, potassium hypochlorite and mixtures thereof. The silicate coating agent may be sodium metasilicate. In order to ensure the formation of the stable coating, the leaching is performed at a pH of 4-6 and more preferably 5. Additionally, the oxidizing agent is maintained at a concentration of substantially 0.6% by weight of the coating composition while the concentration of the silicate coating agent is maintained at at least substantially 1.8×10-3 M/l

Bituminous Fly Ash Release Potential Modeling and Remediation of Arsenic, Boron and Heavy Metals

In Kentucky, approximately 3 million tons of coal fly ash are produced annually at a disposal cost around $20 per ton. Moreover, disposal is becoming a major issue because of the ash\u27s potential to contaminate surface and groundwater with arsenic, boron, heavy metals, etc. Knowledge on the chemistry of fly ash is essential in developing a methodology that can predict release rate(s) and concentration(s) of chemical constituents of environmental concern (pollutants). Currently, there is major concern in the state how to dispose of safely the fly ash generated from the combustion of coal by electrical generating plants. Safe disposal of fly ash with respect to surface and groundwater protection depends on having the know-how and technology to evaluate the potential of a given fly ash to release toxic pollutants and 2) having the know-how to do something about it, assuming that a given fly ash is shown to have the potential to pollute. Kentucky is in major need of the above technologies because a major portion of its electrical needs comes from coal-fired electricity generating plants. The results of this study showed that Kentucky fly ashes were made of three types of solids: 1) chemically water stable solids (SiO, FeO, AlO), 2) chemically water reactive solids (SO4, BO3). and 3) metal-oxides (CaO, K2O) unstable at the pH range of natural water. The selected fly ashes varied from acidic to alkaline because of the chemical make-up of the source coal. Physical appearance of the samples tested varied depending on coal type and furnace. All fly ash samples were mainly composed of glass-like porous beads that varied in chemical composition with respect to Al/Si/Fe ratio and varied in pH from extremely low (pH near 3) to near pH 11. Alkaline fly ash samples were associated with high boron levels and exhibited extremely low potential pH buffering capacity. Potentiometric titrations revealed a fly ash PZCpH somewhere around 4.6 which was approximately midway between the PZCpH of iron-oxides and SiO2. Also, these data revealed that fly ash surfaces exhibited an apparent pH-dependent positive charge. A positive charge of approximately 40 cmolc kg-1, and a negative charge of approximately 40 cmolc kg-1 with intrinsic protonation and dissociation constants of 106.2 and 10-7.8 , respectively). Little if any charge was exhibited between pH 4 to 8.5. Low pH buffering capacity, low pH dependent charge and relatively low PZCpH appeared to make the fly ash samples tested extremely sensitive to pCO2 with respect to pH and boron release. Increasing pCO2 increased boron release but pCO2 had no influence on nickel release. This suggested that nickel was most-likely strongly chemisorbed. Nickel and cadmium adsorption isotherms showed that adsorption maximum took place above pH 6. The acidic fly ash showed a greater metal adsorption potential than the alkaline fly ash. Because boron (the major pollutant detected in the fly-ash samples tested) is weakly held, one should avoid burying such fresh fly-ash in water permeable waste disposal sites

Effect of Fertilizer Salts on Crop Production

Soil consists largely of mineral and organic matter, air, and water. Plants obtain nutrients from mineral and organic matter, oxygen from air, and they use water as a carrier of nutrients from the soil into the root and to the above ground portion of plants. Since soil water functions as a carrier of nutrients from solid fractions of soil into and through plants, it plays a very important role in plant nutrition. Because of this importance, correct chemical balance of the soil solution is necessary for best crop performance. This means that pH of the solution should be in the range 6.0 to 6.6 and the solution should not contain high concentrations of dissolved solid materials (salts)

H\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e2\u3c/sub\u3e Induced Oxidation Proof Phosphate Surface Coating on Iron Sulfides

The present method induces an oxidation-proof ferric phosphate coating on iron sulfide such as pyrite and marcasite. The method includes the steps of placing the pyrite to be treated in a reaction vessel and leaching the pyrite with a coating composition including water, an oxidizing agent and a phosphate coating agent. Examples of oxidizing agents include hydrogen peroxide, sodium hypochlorite, potassium hypochlorite and mixtures thereof. The phosphate coating agent may be potassium dihydrogen phosphate. In order to ensure the formation of the stable coating, the leaching is performed at a pH of substantially 5 and at a temperature of substantially 40° C. Additionally, the oxidizing agent is maintained at a concentration of substantially 0.1% by weight of the coating composition while the concentration of the phosphate coating agent is maintained at at least substantially 10-4 M/l

Does Use of Gypsum Improve Soil Structure in Kentucky?

Gypsum is sometimes recommended as a soil amendment in order to improve structure. Although this practice is often used for reclamation of sodic soils (Na+ saturated) in the western USA, it\u27s value in improving soil structure in Kentucky is questionable. The following discussion explains way

The Effect of Oil Well Brines on Agricultural Fields and Water

What is Brine and Where Does it Come From? Brine is the salty water trapped in rock formations associated with oil and gas deposits. It consists mostly of sodium chloride but can also contain other things such as organics, bromide, some heavy metals and boron. Its source as a pollutant is usually oil stripper wells which produce less than 10 barrels of oil per day with typically a 10:1 ratio of brine to oil. Such wells are distributed throughout Kentucky and are often located on farmland. In some cases, brine rises to the land surface even where no oil wells are present

Formulation Enhanced Transport of a Soil Applied Herbicide

Because pesticides are applied as formulated particles and the affinity of the active ingredient for the formulation is higher than for the bulk water, we hypothesized that a formulation complex could affect active ingredient transport. Our objectives were to investigate the nature and extent of surfactant-atrazine-clay/oxide surface interactions. When atrazine and an anionic surfactant were dried onto plain or Fe-coated sand and leached, atrazine concentrations in the initial leachate were lower in the Fe-coated sand treatment. This was likely due to an electrostatic attraction between the sand and surfactant. When a nonionic surfactant was used, atrazine concentration in the initial leachate was lower through plain sand. This suggests that the affinity of the nonionic surfactant for the Fe-surface is lower than for the silica surface. Using FTIR spectroscopy we have determined that a nonionic surfactant and atrazine will partition into the interlayer of montmorillonite. Atrazine in the interlayer has important implications for herbicide mass transport. The desorption of atrazine will be diffusion controlled and hence less atrazine should be available for transport. However, should these clays become dispersed, they could act as a suspended, highly mobile phase for the particulate transport of atrazine

Identification of Soil-Water Chemical Parameters for the Prediction and Treatment of Suspended Solids in Surface Water Reservoirs of Coal Mine Lands

High concentrations of suspended solids in coal mine sedimentation ponds are a factor in lowering water quality. Colloidal particle settling simulations were carried out in the laboratory to test the influence pH and dissolved solids have on concentration and settling rates of suspended solids. The results of the study reveal that the pH range of colloidal coflocculation for the samples tested is between 3.5 and 4.5. Furthermore, liming simulation of acidic sediments, as expected increased colloid dispersion. This increase was dependent on the magnitude of the sodium adsorption ratio (SAR). The greater SAR systems maintained a greater concentration of colloidal suspended particles. However, for the same SAR value when the ionic strength was increased from 4 meq L-1 to 8 meq L-1, sedimentation rate of colloidal particles decreased. The data also show evidence that for the same SAR values when substituting magnesium for calcium, the rate of particle settling increased for one sample but decreased for another. This unexpected behavior is under further investigation

Identification of Soil-Water Chemical Parameters for the Prediction and Treatment of Suspended Solids in Surface Water Reservoirs of Coal Mine Lands

High concentrations of suspended solids in coal mine sedimentation ponds are a factor in lowering water quality. This study focuses on the influence dissolved solids have on concentration and settling of suspended solids. Water samples from sedimentation ponds in Eastern and Western Kentucky were used to evaluate water composition in such ponds. Spoil samples from surface mine sites in both parts of the state were used to evaluate water composition released from the spoils upon introducing water. The results demonstrate that water quality emanating from coal spoils of Eastern and Western coal mines is dependent on the type of spoil and/or geologic strata represented. Water composition of randomly selected sedimentation ponds revealed that the relationship between electrical conductance (EC) in mmhos cm-1 and ionic strength (I) of water is I = 0.012 [EC]. Furthermore, it was determined that there is a linear relationship between the repulsive index, RI = [(0.012)(EC)]-1/2 (based somewhat loosely on double-layer theory), and suspended solids. Kinetic data on settling of suspended solids has shown that upon increasing the ionic strength of the water (consequently decreasing RI), the rate of settling increased dramatically. The critical RI at which complete removal of all suspended solids, estimated by graphic extrapolation, is shown to be dependent on the percent base saturation. The data also demonstrate that the critical RI (RI at maximum flocculation) varies depending on the spoils mineralogical and chemical composition. The overall study shows that decreases in suspended solids in coal mine sedimentation ponds can be brought about by relatively small increases in ionic strength. Several approaches as to how one might increase water ionic strength in sediment ponds are discussed

Kinetics and Mechanisms of Atrazine Adsorption and Desorption in Soils Under No-Till and Conventional Management

Both soils (Maury silt loam and Sadler) exhibited three apparent mechanisms of atrazine adsorption. The first two mechanisms were very rapid (10 minutes) and were assigned to soil-clay surface adsorption reactions via hydrogen bonding. The quantity of atrazine involved in these two reactions for the 0.5 mg/1 solution atrazine varied, depending on the soil, from 67 μg/100 g clay to 219 μg/100 g clay. The reason there were two possible atrazine sinks in this range of atrazine adsorption was believed to be the presence of two types of reactive surfaces, the clay inorganic phase and the organic carbon phase. The latter phase exhibited more influence on the Maury silt loam soil than on the Sadler soil, where the Maury silt loam soil contained more organic carbon than the Sadler soil. The third mechanism involved an atrazine condensation mechanism. It was a relatively slow reaction and it appeared to persist for at least 2 hours. This mechanism accounted for about three fourths of the total atrazine adsorbed. After 75 minutes of solution flow the total atrazine adsorbed by the soil clay samples varied from 333 μg/100 g to 710 μg/100 g. Reversibility of the adsorption process was shown to be limited. Approximately one-third of the adsorbed atrazine was desorbed after a 2 hour leaching with l mmol L-1 CaCl2 solution. The desorption process was shown to be controlled by two types of reactions. A short rapid one and a long extremely slow one (diffusion controlled). The above findings suggest that the amount of atrazine leaching into surface water or groundwater would depend on the amount of time atrazine had to react with the soil. If it rained immediately following atrazine application then most of the atrazine would be carried in the runoff, making water the main mechanism of atrazine movement. If, on the other hand, a significant amount of time passed after atrazine was applied then a much smaller proportion of the applied atrazine would be leached, making soil erosion the main mechanism of atrazine movement. Equations for all these processes have been developed to aid in modeling the movement of atrazine during rain fall events