The determination of exchangeable aluminium in soils

Soil Research ◽  
1964 ◽  
Vol 2 (1) ◽  
pp. 76 ◽  
Author(s):  
I Little
Keyword(s):  
Potassium Chloride ◽  
Sodium Hydroxide ◽  
Potentiometric Titration ◽  
Ammonium Acetate ◽  
Ph Dependent ◽  
Aluminium Compound ◽  
Leaching Procedure

A leaching procedure employing 1N potassium chloride was found to yield satisfactory estimates of exchangeable aluminium in subsoil samples. The use of 1N ammonium acetate solutions as extractants was not recommended. When buffered at pH 4.8 these solutions gave low results, whereas at pH 4.0 there was some attack on hydroxy-aluminium polymers, which led to erroneous results, particularly in sesquioxidic soils. Satisfactory estimates of exchangeable aluminium in subsoils were obtained by potentiometric titration of soil suspensions in 1N potassium chloride with 0.1N sodium hydroxide, provided allowance was made for the contribution of pH-dependent charge between pH 4.0 and 5.5. This procedure gave values consistently lower than those obtained by leaching with 1N potassium chloride, and of the order of 81 % of these. This was consistent with the formation of an aluminium compound with the formula Ak6(OH)153+ whose existence has been postulated by other workers.

The A˚bo Akademi Database: Fuel Characterization

2005 ◽  
Author(s):  
Maria Zevenhoven ◽  
Patrik Yrjas ◽  
Rainer Backman ◽  
Bengt-Johan Skrifvars ◽  
Mikko Hupa
Keyword(s):  
Trace Metals ◽  
Ammonium Acetate ◽  
Chemical Fractionation ◽  
Ash Deposition ◽  
Agricultural Crops ◽  
Insufficient Information ◽  
The Past ◽  
Fuel Characterization ◽  
Leaching Procedure

Standard fuel analyses have shown to provide insufficient information for proper prediction of ash deposition. Therefore, chemical fractionation, i.e. a stepwise leaching procedure, has been developed in the past. It has been used extensively for determination of the distribution of ash forming matter both in coal, peat, waste and biomass fuels. With this method fuels are leached in three steps, i.e. leached with water, ammonium acetate and hydro chloric acid respectively. This paper presents the fuel database developed at A˚bo Akademi University. The database contains over 100 fuels, i.e. coal, peat, bark, wood derived fuels, agricultural crops and waste fuels. Standard fuel analyses, stepwise leaching results, thermodynamic melting calculations and SEM pictures are available for the majority of these fuels. For 11 fuels also trace metals were analyzed.

Chemical Forms of Ash-Forming Matter in Woody Fuels for FBC

2005 ◽  
Author(s):  
Johan Werkelin ◽  
Maria Zevenhoven ◽  
Bengt-Johan Skrifvars ◽  
Mikko Hupa
Keyword(s):  
Hydrochloric Acid ◽  
Ammonium Acetate ◽  
Ionic Species ◽  
Water Soluble ◽  
Chemical Fractionation ◽  
Soluble Calcium ◽  
Combustion Processes ◽  
Low Solubility ◽  
Leaching Procedure

The prediction of the ash behavior in combustion processes is enhanced by the determination of the ash-forming matter in the fuel. The scope of this work was to characterize Scandinavian wood fuels by studying the wood, bark and leaves from a spruce and an aspen. Chemical Fractionation, a step-wise leaching procedure that treat the fuel in water, ammonium acetate and hydrochloric acid, was used to determine the solubility of the ash elements. The resulting solutions were further analyzed on ionic species, which was coupled to the presence of salt compounds in the original biomass tissues. The leaching procedure dissolved nearly 100% of the ash-forming matter. The phosphorus (P), chlorine (Cl) and some of the sulfur (S) were readily leached with water and found present as HPO42−, SO42− and Cl− in the solutions. The simultaneous dissolving of potassium (K) in this step proved the presence of water soluble potassium salts in the biomasses. The remaining K after the water treatment and all magnesium (Mg) dissolved completely in the ammonium acetate step together with a large part of the tissues’ calcium (Ca) and manganese (Mn). The remaining Ca after the second step was leached in hydrochloric acid together with equivalent amounts of oxalate ions, C2O42−. This proved the presence of acid soluble calcium oxalate in the tissues, a salt with low solubility in neutral pH.

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