Spectrographic Trace Analysis of Tin in the Presence of Large Amounts of Iron

It is possible to lower the inferior limit of spectrographic trace analysis of Sn in iron and steel1 if the Sn is separated by coprecipitation from the solution obtained by dissolving the sample in a mineral acid. The coprecipitation of Sn2+ 2•3 was in these experiments tested with CdS which is formed in the investigated solution. The amount of Cd2+ must be known because the spectrographic lines of Cd were used as reference lines, i. e. as an internal standard

Metal Ion Exchange by Natural Zeolites

The influence of pretreatment on the capacity and selectivity of natural zeolite for Zn2+ and Mn2+ ions has been studied. Natural tuff (sample 1), consisting mainly of zeolite clinoptilolite, was converted into the Na+ form by conditioning with 2 M NaCl at 22 °C (sample 2) and 70 °C (sample 3), respectively. Simultaneously, 0.26, 0.31, 0.38 mmol Zn2+ and 0.20, 0.23, 0.30 mmol Mn2+ were taken up by 1.00 g of zeolite samples 1, 2 and 3, respectively. The results show that zeolites converted to the Na+ form at 70 °C possess the highest capacity for metal ions. For all the zeolite samples tested, zinc was more selectively removed than manganese. The amount and composition of exchangeable cations as well as their impact on ion-exchange performances of zeolite in the process of Zn2+ and Mn2+ removal were determined

Ion Chromatographic Analysis of Anion from Slag Elution

Anions from blast furnace slag (F~, Cl", Br", NO3, NO2 and SO|") significantly influence the environment, human health, and the stability of structures. Particular attention is paid to reactions between the slag and the solution of the anions in question (of defined concentration) in the duration of 1 hour to 30 days. The anions were determined by means of the ion chromatographic analysis modified for different proportions of anions in eluents. The results of elution within reactions between slag and media point to the inertness of the system. The fluoride saturation factors of the system were experimentally determined and calculated with the help of distribution coefficients

The Phase Composition of Electric Furnace Slag

Elementary and phase composition as well as micrography of the electric furnace slag were examined. The base of slag is made from phases containing Fe, Mn and Ca. Grains differ in size and shape, they cling together to form bigger or smaller agglomerates, depending on separated fractions. Relative distribution of identified phases in separated fractions is presented and the possibility of phase separation by means of successive fragmentation and sieve analysis was noticed. The slag defined in that way could find application in cement production and construction industry. The electric furnace slag deposits which pollute the water and ground as well as disfigure the environment can thus be reduced

Influence of the Leather Industry on the Pollution of Coastal Sediments by Chromium in the Zadar Area (Eastern Adriatic)

U radu je ispitan utjecaj dugogodišnjeg ispuštanja neobrađenih otpadnih voda Tvornice kože Zadar na raspodjelu kroma u sedimentu uvale Brodanov jaz (Zadar, srednji Jadran). Ispitivanja su provedena na četiri lokacije duž uvale (ušće P1, početak P2, sredina P3 i kraj uvale P4), a za usporedbu uzet je i uzorak sedimenta na onečišćenoj lokaciji 20 km sjevernije od uvale Brodanov jaz, u Ninu (R). Određivan je maseni udjel kroma u 3 granulometrijske klase sedimenta (A: 0,063-2,0 mm, B: 0,010-0,063 mm, C: < 0,010 mm). Maseni udjel Cr u sedimentu na ušću (P1) znatno je veći (6 puta) nego maseni udjel kroma u sedimentu na kraju uvale (P4). Na ušću (P1) i početku uvale (P2) maseni udjel kroma je u prosjeku 25 puta veći nego na referentnoj lokaciji u Ninu (R). Maseni udjel kroma u svim uzorcima obrnuto je proporcionalan promjeru čestica sedimenta, tako da sitnije klase sedimenta (C i B) imaju u prosjeku oko 4 puta više kroma nego najkrupnija klasa (A) istih uzoraka. Dobivena raspodjela čestica ukazuje na to da su povećane količine kroma u sedimentu uvale Brodanov jaz antropogenog izvora, tj. da potječu iz Tvornice kože Zadar.The influence of the long term discharge of untreated wastewaters from the leather factory in Zadar on the distribution of chromium in the bay of Brodanov Jaz has been investigated in this study. The investigation was performed at four locations along the bay (at the mouth - P1, the beginning - P2, the middle - P3 and the end - P4 of the bay). A sediment sample was also taken at an unpolluted location near the town of Nin, 20 km to the north of the Brodanov Jaz bay, for the purpose of comparison. The chromium concentration was determined in 3 granulometric competition of the sediment (A: 0.063-2.00 mm, B: 0.010-0,063 mm, C:<0.010 mm). The highest concentracion of chromium was observed in the sediment taken nearest to the wastewater outlet. The concentration of Cr in the sediment at the mouth (P1) was considerably higher (6 times) than at the end of the bay (P4). At the mouth (P1) and at the beginning of the bay (P2) Cr concentration was about 25 times higher than at the reference location in Nin. Concentrations of Cr in all samples were inversely proportional to grain size, so the finest fractions of sediment (C and B) contained about 4 times higher Cr concentrations than in the large grain fraction (A) of the same samples. The obtained distribution of Cr in the bay of Brodanov Jaz indicates that the increased Cr concentrations in sediment came from the leather industry, and that they are of anthropogenic origin

Evaluation of Croatian Clinoptiloliteand Montmorillonite-rich Tuffs for Ammonium Removal

In this Study, the ability of a Croatian clinoptiloliteand montmorillonite-rich tuffs to take up ammonium from aqueous Solutions was investigated. Montmorillonite tuff was converted into the Na+ and H+ form by treatment with Na2CO3 (w = 3-5%) and the solution of H2SO4 (w = 15%). The properties of clay modified in this way were investigated as well. The results show that the clinoptilolite tuff efficiency for ammonium removal is far superior (by 45-50%) to the removal efficiency of montmorillonite tuff. Treatment of montmorillonite tuff with Na2CO3 resulted in a slight improvement of its ammonium exchange efficiency. Acid modification of montmorillonite tuff causes a considerable decrease of ammonium exchange. Maximum loadings in ammonium exchange in clinoptilolite tuff, montmorillonite tuff, alkaline modified montmorillonite tuff, and acid modified montmorillonite tuff, as calculated by the Langmuir equation, are 1.20, 0.54, 0.64, and 0.21 mmol g-1 NH4+, respectively

Aqueous Leachate from Electric Furnace Slag

In manufacturing manganese and carbon steel in the basic electric arc furnace, 70 to 80 kg of slag per tonne of steel is produced, whereas the grey cast production results in 30 to 40 kg of slag per tonne of grey cast. Such large slag volumes require special care for their disposal at landfills near steel and rolling mills. It is therefore necessary to examine the chemical stability of slag under various conditions. The paper reports examinations of the chemical and phase composition of slag, as well as the number of anions and cations. The number of anions and cations in water eluates was determined in order to define the influence of such material on the environment. The phase composition of slag was determined by the X-ray diffraction method. Eluated anions (F-, Cl-, NO2-, Br-, NO3- and SO42-) were determined by ion-chromatographic analysis. Eluated cations (Na+, K+, Ca2+ and Mg2+) were established by spectrometric atom absorption. Changes in pH, conductivity and chemical composition of water eluates were monitored for 96 hours. The results have shown that the examined slag material could, with regard to its chemical and phase composition, constitute a stable Fe-Mn-Ca silicate material. However, elution of the examined components, along with the change in conductivity and pH value, implies that slag is not chemically inert and that therefore the problem of slag disposal has to be approached paying special attention on its potential impact on the environment

Influence of X-ray Radiation on the Phase Composition and Morphology of Electric Furnace Slag, Clinker, and Plaster

The effect of X-ray irradiation upon the structure and morphology of samples of clinker, plaster, and electric furnace slag was studied. Slag was obtained in the process of austenite manganese steel casting. The research objective was to determine the stability of these materials under radiation. The changes that occurred were analyzed by X-ray diffraction and scanning electron microscopy. The diffractograms show changes in the profile, number, relative intensity of diffraction lines, and measured width values at half the maximum height. The micrographs show swelling and cracking of grains. As the radiation time was prolonged, this phenomenon became more evident, which points to the apparent change in the size and shape of the slag, clinker, and plaster grains, i.e. the elementary components of cement