Showing papers on "Lime published in 1986"

Aqueous Solubility Relationships for Two Types of Calcium Silicate Hydrate

Abstract: There are many published values for the concentrations of lime and silica in the aqueous phase which is in contact with calcium silicate hydrate. These have been collected, carefully analyzed, and found often to be apparently inconsistent. When, however, they are interpreted as having come from an aqueous phase which is in near equilibrium with one or another of two possible modifications of calcium silicate hydrate, almost all the data are rationalized. Some important insights emerge for the understanding of the complex processes which occur during the hydration of tricalcium silicate.

Interactions of surface drying and subsurface nutrients affecting plant growth on acidic soil profiles from an old pasture

Abstract: Previous studies on soils from old pastures in southern New South Wales have demonstrated that nutrients have accumulated at the soil surface, but that the 40-100-mm depth layer in many profiles has become strongly acidic (e.g. pH 4.7), and high in extractable aluminium. Poor growth of subterranean clover has occurred on such soils during dry periods and may be associated with poor root growth in the acidic, nutrient-poor subsurface layers. Possible nutritional causes of these observations were investigated using reconstituted soil profiles. The root and shoot growth of subterranean clover, wheat, oats and lucerne were compared in unamended profiles and in profiles amended by applying nutrients or calcium carbonate (lime) to correct the more obvious deficiencies of the subsurface layers. Subterranean clover grew well as long as the surface soil remained moist, so that plants could utilise the nutrients potentially available within it. When the surface (0-40 mm) was allowed to dry but the subsurface layers remained moist, growth was poor unless phosphate was applied to the moist layer. Subsurface application of lime alone was ineffective. Nitrogen application increased clover growth in the presence of added phosphate or surface moisture, but nitrogen alone did little to alleviate the effects of surface drought. Wheat, and to a lesser extent oats, responded to subsurface lime when the surface was moist, and both responded to subsurface phosphate when the surface was dry. Lucerne responded to subsurface phosphate similarly to subterranean clover but the response was more than doubled in the presence of additional borate and lime. Lime without borate was not effective. When the surface was maintained moist, liming both the surface (0-40 mm) and subsurface layers improved the response over liming the subsurface layer only. The results suggest that declining fertility and productivity in old pastures developed on acid soils may not be rectified by liming alone, but that cultivation, ripping or drilling of phosphate, and in some cases addition of borate, may be required to improve the penetration of nutrients, particularly phosphorus, to greater depth.

Microbial biomass and mineralizable nitrogen in solonetzic soils: Influence of gypsum and lime amendments

Abstract: Microbial biomass-C and -N and net mineralizable C and N were determined in the Ap horizon of several Solonetzic soils receiving gypsum (CaSO4·2H2O), lime, and NH4NO3 amendments. The main effect of gypsum, measured in long-term field experiments and laboratory studies, was to reduce soil microbial N by 10–43%, increase the C-to-N ratio of the biomass, and reduce mineralizable N by 10–54% and the resultant N mineralization potential. For the field study, a close relationship (r2 = 0.82) was evident between microbial biomass N and the N mineralization potential. Both gypsum and NH4NO3 when applied alone or together changed soil chemical properties especially soil pH which decreased from approximately 6.0 to 5.0. Applications of NH4NO3 alone, however, did not influence microbial biomass or activity; while combined gypsum and NH4NO3 applied together had similar effects as gypsum alone. In the laboratory study, lime additions increased soil pH, microbial biomass and N mineralization. Small amounts of lime mixed with the gypsum, to prevent a drop in soil pH, corrected the deleterious effects of the gypsum on microbial biomass and mineralizable N for one of the Solonetzic soils. The results show the direct effect of gypsum on microbial activities and demonstrate inter-relationships between changes in soil chemistry of Solonetzic soils and microbial biomass and activity.

Surface charge characteristics and lime requirements of soils derived from basaltic, granite and metamorphic rocks in high rainfall tropical Queensland

Abstract: The cation and anion exchange capacities of a large number of soils formed on basaltic, granitic, and metamorphic parent materials in the high rainfall area (approximately 4000 mm) of tropical north Queensland have been examined. Aspects studied included the changes in CEC and AEC between pH 4 and pH 6, the relative amounts of permanent and variable charge over this pH range, and the lime requirements of these highly weathered soils. A distinction is made between the Total Cation Exchange Capacity (CECT), defined as the Ca + Al adsorbed, and the Basic Cation Exchange Capacity (CECB), which is the Ca adsorbed. At low pH, CECB may be much less than CECT. The CEC, increase with pH in the highly oxidic basaltic soils is largely due to changes in surface charge, while in the granitic and metamorphic soils, increasing occupation of exchange sites by Al as pH decreases is the factor responsible for the increase in CECB. A good estimation of CECB at soil pH is obtained with a previously described compulsive exchange method, and there is high correlation between CECT at soil pH and the Effective Cation Exchange Capacity (= Ca + Mg + K + Na + Al). The amount of lime required to raise soil pH to pH 5.5 in the granitic and metamorphic soils was equivalent to the amount of exchangeable Al, but in the basaltic soils the lime requirement was two to three times greater than the amount of exchangeable Al.

Agricultural use of wood ash as a fertilizer and liming material

Abstract: Wood-derived boiler ash was mixed with two acid soils at rates equivalent to 0, 2.24, 4.5, 9.0, 17.9, and 35.9 metric tons/ha to evaluate changes in extractable nutrients and soil pH. Concentrations of extractable P, K, and Ca increased linearly with application rate. Soil pH increased linearly with the logarithm of the application rate. The ash was compared with commercial potash fertilizer and agricultural limestone. The equivalent neutralizing value was about half of that for agricultural limestone. 4 references.

Effects of deep ripping, direct drilling, gypsum and lime on soils, wheat growth and yield

Abstract: In northeast Victoria, wheat crops often have patches of stunted and chlorotic growth which result in overall yield depressions of about 25%. Root defects are common in the stunted patches, and are associated with subsoil hard-pans and acid soils. In 1981, two experiments were commenced aimed at alleviating the soil physical and chemical problems. Treatments involved gypsum applications (0 and 5 t ha −1 ) and deep ripping (0-, 20- and 40-cm depths), followed by either cultivation or direct drilling of wheat for 3 years. In 1982, the experiments were split and lime (0 and 2.5 t ha −1 ) was applied as a main treatment. In 1981, deep ripping increased wheat root and top growth during winter, while gypsum depressed growth. On one experiment, waterlogging subsequently resulted in crop loss; on the other experiment grain yields showed an increase of 0.3 t ha −1 after deep ripping to 40 cm depth, and a reduction of 0.3 t ha −1 due to gypsum. In 1982, drought and frost reduced yields, and treatments had little effect on wheat yields. Penetrometer testing showed that ripped soils were still loose on one site, but on a red duplex soil, the subsoil had partially re-compacted, especially under traffic. Where soil was ripped then direct drilled, gypsum had a marked effect in reducing penetrometer resistance, and this effect was still evident in the final year. In 1983, cultivation and traffic increased penetrometer resistance while direct drilling maintained a lower resistance in loosened subsoils. Direct drilling gave yields equivalent to those with cultivation. An initial deleterious effect of gypsum on wheat growth was reversed later in the season, and a combination of lime, deep ripping and gypsum gave the highest yields at both sites. Deep ripping and liming on strongly acid and compacted yellow duplex soils give considerably improved yields for wheat. On red duplex soils, however, the longevity of the effect of deep loosening is still in question, and use of gypsum requires further research.

The influence of contaminating (fossil) carbonate and the variations of delta (super 13) C in mortar dating.

Abstract: The influence of the aggregate in mortar dating is examined. Sample activity as well as isotopic fractionation approach the expected values at lower yields of the preparation reaction of the counting gas. Good results are obtained at low fossil carbonate concentration. 813C cannot give information about this concentration but preliminary visual and chemical analysis of the mortar makes prediction of sample validity possible. INTRODUCTION It is well known that 14C dating does not date archaeologic events but only the materials found in an archaeologic context. Thus, there may be an important interval between the age of the material and the archaeologic event. A good example of this is 14C dating wooden beams used in construction. The 14C dated tree rings can easily be a century older than the building, itself. This problem becomes even more severe if we consider re-use of material. This problem can be avoided by using mortar as a dating material. Traditionally mortars were made essentially of lime and sand. Different limes were used, quicklime and hydraulic lime. Quicklime (CaO) is obtained by burning (CaCO3) over a fire at ca 1000°C. When water is added it forms Ca(OH)2 and hardens by absorption of atmospheric CO2. Hydraulic lime is obtained by burning argillaceous limestone. It contains aluminates and silicates which harden with water. Younger mortars tend to be more hydraulic than older mortars. The hydraulic index framed by Leduc and Chenu (1912) provides a useful parameter to classify mortars. This index is defined as Al203 + Fe203 + S102 soluble CaO + MgO This is, in fact, the ratio between the clay and the lime fractions. Fat limes have values up to 0.1; values > 0.5 indicate that the material is cement rather than mortar. In between are mortars which are more or less hydraulic. Besides lime, mortars also contain sand and aggregate which are used as charge. Their purpose is to enlarge the volume of the mortar and to avoid cracks. Several laboratories have been working on mortar dating since 1964. Some obtained very good results (Delibrias & Labeyrie, 1965); others obtained dates that were far too old (Stuiver & Smith, 1965). In summary, we can say that, theoretically, mortars containing lime ought to be 14C datable since hardening time is short compared to the half-life of 14C. How-

Effect of Lime and Organic Matter on Soybean Seedlings Grown in Aluminum-toxic Soil

Abstract: Organic matter is believed to be able to reduce Al toxicity in Ultisols. Since little information is available to substantiate this hypothesis, a greenhouse experiment was conducted to compare the effects of organic matter and lime on soybean [Glycine max (L.) Merr.] plants grown under increasing Al stress in a Bradson (Typic Hapludults) soil. Treatments, replicated three times, were 0, 25, 50, and 100 mg Al kg⁻¹ pot⁻¹, 0, 5, and 10% wheat (Triticum aestivum L.) straw, and the equivalent of 0, 1, and 2 Mg CaCO₃ ha⁻¹. After thorough mixing and incubation of the growth medium at field capacity for 20 d, five soybean seeds were germinated per pot and the five seeds allowed to grow for 30 d. The results indicated that shoot and root growth were severely affected by increased Al treatments. Aluminum toxicity started to seriously affect plant growth at 50 mg Al kg⁻¹, and plants were hardly growing at 100 mg Al kg⁻¹. However, plant growth in the Al-toxic soil was improved substantially by the application of wheat straw or lime. The data suggest that treatments with wheat straw produced taller plants and greater dry weight contents of roots than was found in plants grown only with lime. Lime alone yielded good results, but lime in the presence of organic matter was more effective in reducing the effect of Al toxicity. The plants receiving wheat straw still contained relatively high levels of Al (3.7–7.4 mmol kg⁻¹) in their shoots, but little damage could be detected. A tendency toward a decrease in N content was noticed in shoots of plants grown in the presence of wheat straw, but this was believed to have been caused by a temporary immobilization of N because of the application of straw. It was concluded that organic matter was as effective as lime in reducing Al toxicity.

Microstructural development in cured soil-lime composites

Abstract: The bond which develops during curing between soil particles in the presence of lime and moisture is a result of the growth and the development of a newly formed cementitious phase (or phases). For the particular soil studied, appreciable reaction occurs between soil particles and lime only at elevated temperature, in a moist environment The growth and development of the new phase is accompanied by an increase in compressive strength of the soil-lime composites. Scanning electron microscopy (SEM) studies show the phase to consist of an interlocking network of fine platelets and fibres, and although no direct determination of composition was possible, evidence from X-ray analysis and thermal analysis shows that the new phase is poorly crystalline and probably consists of a hydrate of calcium silicate or calcium aluminate.

The impact of pasture improvement on the soil solution chemistry of some stagnopodzols in mid-Wales

Abstract: . The impact of three methods of pasture improvement on soil water chemistry were studied: ploughing plus 15 t ha-1 lime c. 40 years ago, 5 t ha-1 surface spread lime c. 20 years ago and surface cultivation with 7 t ha-1 lime plus compound fertilizer 10 years ago. Soil solution was sampled using tensionless lysimeters and porous ceramic cups. Concentrations of several solutes were higher in the treated soils than a control, including solutes not added in lime or fertilizers. Calcium, magnesium and bicarbonate concentrations showed the largest increases; these were apparent in all horizons, and all treatments. Bicarbonate had become the dominant anion. Solute concentrations varied between treatments and were related to the amount of an element added rather than time since treatment. Highest mean calcium concentrations, 6.25 mg l-1 were still low compared with drainage from lowland arable soils but could have a significant impact on the calcium-poor surface waters of the uplands.

Comparison of Several Lime Requirement Methods on Coarse-textured Soils of Northeastern Nebraska

Abstract: Soils of the eastern Sandhills of Nebraska are becoming progressively more acid as a result of the development of irrigation and subsequent use of high N fertilizer amounts for corn (Zea mays L.). Chemical determinations of lime requirement are expected to vary in their applicability to these poorly buffered, sandy soils. The objective of this research was to compare the abilities of selected chemical methods of determination of lime requirement to predict lime needs of sandy soils. The lime requirement values of 74 acid sandy soils from northern Nebraska were determined by eight methods. Correlation and regression were used to compare these values with those obtained by incubating the soils with varying amounts of lime in the laboratory. The validity of the CaCO₃ incubation method as a standard method was confirmed by a Ca(OH)₂ titration procedure. Most of the soils studied required <4492 kg of lime ha⁻¹ to attain soil pH 6.5. The relationship between the values from chemical determination of lime requirement with those from incubation were essentially linear for all methods. Although the nature of the relationship as expressed in the intercepts and slopes of the regression curves and the precision varied among methods, values from all methods were correlated with lime requirement values from incubation. Determination of the correlations among methods showed that lime requirement values for each method were highly correlated with those from every other method included in the study. Correlation studies of lime requirement values for five methods with selected soil properties showed that no single property was correlated with all methods. However, soil pH, clay content, cation exchange capacity, and Mn and Al contents were correlated with values from at least one method.

Removal of Antimony from Aqueous Systems

Abstract: Antimony(III) is readily removed from aqueous systems by coprecipitation with ferric hydroxide and by adsorbing colloid flotation with ferric hydroxide and sodium dodecyl sulfate. Aluminum hydroxide is not effective in removing antimony. Precipitation with lime requires quite large quantities of lime in order to reduce residual Sb levels to desired levels. Precipitation of the sulfide in the presence of Fe(II) or Fe(III) may produce low residual concentrations, but runs the risk of exposure to highly toxic hydrogen sulfide.

Liming in Sweden

Abstract: Air-borne pollutants have acidified 90,000 km of running water and at least 18,000 of Sweden's 90,000 lakes. In 1977 a national liming program to mitigate the effects of acidification in surface waters started with governmental support. Governmental subsidies usually amount to 85 % of the total liming cost but can in rare cases be extended to 100 % when waters of great national interest are threatened. The main liming agent is limestone of the size 0 to 0,2 mm. In lakes lime is spread by pontoon boats, helicopters and other vehicles. In running waters dosers and diversion wells are used. By 1985, the national liming program has been able to lime approximately 3,000 lakes and 100 streams.

Comparisons of the fertilizing and liming properties of lime-treated sewage sludge with its incinerated ash

Abstract: Two field experiments were conducted to compare the fertilizing and liming properties of dried lime-treated sewage sludge with its incineration product (ash). One experiment used a mixture of ryecorn and ryegrass on a relatively fertile soil and the other lucerne on a strongly acidic and phosphorus deficient soil.

Inhibiting leaching of metals from catalysts and sorbents and compositions and methods therefor

Abstract: During use in hydrocarbon conversion processes, sorbents, e.g. for carbon and metals, and catalysts become contaminated with metals, e.g. heavy metals such as vanadium, nickel and sodium. Leaching of heavy metals can be sharply reduced by treatment of such spent particulate materials with alkaline earth metal compound, e.g. lime, calcium fluoride, calcium sulfate, and barium chloride. Surprisingly, calcium chloride, calcium carbonate, sodium bicarbonate are relatively ineffective.

Process for manufacturing a lightweight aggregate

Abstract: Lightweight aggregate for use in the building industry is produced by pelletizing or granulating pulverized fuel ash or other siliceous material with a binder comprising lime in an amount less than 5% by weight based on the weight of the mixture of lime and siliceous material and curing the pellets or granules at a temperature within the range of from 35° C. to 100° C. in an atmosphere saturated with water vapor. The amount of lime added as binder is preferably within the range of from 1 to 4.5% by weight and curing temperature is preferably within the range of from 50° to 85° C. Preferably the pelletizing process is also carried out at an elevated temperature within the range of from 35° C. to 100° C.

Lime sludge kiln

Abstract: A kiln for reclaiming quick lime from calcium carbonate sludge formed in the production of cooking liquors in a wood pulping process for the production of paper. The kiln provides increased output with lower energy input due to: measurement and control of oxygen content in the kiln; non-air mixing burner; castable refractory liner with tumbler ribs; a heat transferring chain system; and a variable speed exhaust fan and air flow control. The output of the kiln was increased by more than ten percent along with a forty-five percent improvement in energy efficiency at substantial cost reduction due to its efficient use of energy.

Veld compositional response to fertilization in the tall grassveld of Natal

Abstract: The plant species compositional response of veld at Ukulinga to application, over 30 years, of nitrogen, phosphate and lime is reported. Two types of nitrogen fertilizer were applied at four levels with and without phosphate, lime and lime + phosphate. Each treatment was replicated three times. Data on veld composition were obtained using a Levy bridge and observing 100 points per plot. The response of the veld to fertilization was examined using detrended correspondence analysis, providing simultaneously a samples and species ordination. The amount, but not the form, of nitrogen fertilizer strongly affected veld composition. Phosphate and lime had a lesser effect on veld compositon, but the presence of phosphate enhanced the effect of nitrogen on some grasses. S. Afr. J. Plant Soil 1986, 3: 1–10

Deterioration of brick masonry caused bi acid rain

Abstract: The effect of acid rain on bricks and mortar is considered for bridge, the main reaction is the dissolution of the glassy phase; for lime-containing mortars, the acid dissolution of the carbonated lime. The overall deterioration is mainly due to the mechanical effect of the recrystallisation of solubles salts. Photographs, references.

Process for the separation of sulfate ions from waste water

Abstract: 1. A method of separating sulphate ions from industrial waste water by (A) precipitating difficulty-soluble calcium aluminate sulphates by adding reactive aluminium oxide and/or calcium aluminates to the waste water, with mechanical mixing and adjustment of the pH with Ca(OH)2 to a value in the range from 11.2 to 11.8 and (B) separation of the calcium aluminate sulphates formed, characterised in that in step (A) (A1) the reactive aluminium oxide and/or the calcium aluminate or aluminates are added simultaneously with or after adjustment of the pH, (A2) the pH of the resulting precipitation system is kept constant at 11.2 to 11.8 during the entire precipitation reaction by adding Ca(OH)2 in solid form or in the form of milk of lime, and (A3) the precipitation reaction is brought about at a temperature of 25 to 35 degrees C.