Hardness Salts Research Articles

Indirect electrochemical synthesis of active oxygen in dilute sulfate solutions

Anodic oxidation of dilute solutions of sodium sulfate was developed to generate oxidants into aqueous solutions with a diaphragm electrolyzer, which consisted of titanium anodes covered with mixed oxides of iridium, ruthenium and tin, a titanium cathode, and Teflon cation-exchange membrane. An electronic device was created for continuous self-purification of cathode surface from hardness salt deposits. The anodic products of electrolysis were molecular oxygen and sodium persulfate. It should be noted that sodium persulfate was the only active oxidant. The synthesized anolyte was tested for its oxidizing activity towards certain metabolites and toxicants. Disinfecting properties of anolyte were detected towards gram-positive and gram-negative bacteria. The comparison of redox potentials of commercial samples of persulfate and the synthesized anolyte showed that the redox potential value for the anolyte is much higher than for solutions with the same concentration of commercial persulfate.

Electrochemical Synthesis of Oxidants in Dilute Sulfate Solutions and Active Oxygen Donor Determination

Anodic oxidation of dilute solutions of sodium sulfate was developed to generate oxidants into aqueous solutions with a diaphragm electrolyzer, which consisted of titanium anodes covered with mixed oxides of iridium, ruthenium and tin, a titanium cathode, and Teflon cation-exchange membrane. An electronic device was created for continuous self-purification of cathode surface from hardness salt deposits. The anodic products of electrolysis were molecular oxygen and sodium persulfate. It should be noted that sodium persulfate was the only active oxidant. The synthesized anolyte was tested for its oxidizing activity towards certain metabolites and toxicants. Disinfecting properties of anolyte were detected towards gram-positive and gram-negative bacteria. The comparison of redox potentials of commercial samples of persulfate and the synthesized anolyte showed that the redox potential value for the anolyte is much higher than for solutions with the same concentration of commercial persulfate.

Studies of scale formation and optimization of antiscalant dosing in multi-effect thermal desalination units

Scaling of heat transfer surfaces is of great concern for the performance of the thermal desalination process working on seawater, whether it is for multistage flash or multi-effect evaporation. Lot of work has already been carried out for the development of antiscalants for inhibiting/minimizing the scaling. The normal concept of scale formation is due to inverse solubility of hardness salts in the seawater with temperature. Apart from temperature, reasons for scales differ by some factors in case of multi-effect desalination units than that of multi-flash units as experienced in operation of six multi-effect desalination units. As such for taking care of such additional scaling factors, dosing rates of the same antiscalant product is almost double or sometimes even more, in multi-effect evaporators than that in multistage flash units.The purpose of presentation of this paper is to identify these additional factors responsible for scale formation in multi-effect desalination units, other than temperature, with illustrations wherever possible and case study of optimization of dosing rate of antiscalant in 5 million gallon per day capacity multi-effect thermal desalination unit at one of the thermal desalination plants of Federal Electricity and Water, U.A.E. The paper is concluded with the general suggestions for minimizing scales in multi-effect thermal desalination units.

Prevention of Scale Formation in Heat Exchanger Pipes by Using Magnetic Field

The possibility of using the magnetic field technique in prevention of forming scales in heat exchangers pipes usinghard water in heat transfer processes, also the studying the effective and controllable parameters on the mechanism ofscale formation.The new designed heat exchanger experimental system was used after carrying out the basic process designs of thesystem. This system was used to study the effect of the temperature (40-90 °C) and water flow rate (0.6-1.2 L/min) onthe total hardness with time as a function of precipitation of hardness salts from water and scale formation.Different magnetic field designs in the heat exchanger experimental system were used to study the effect of magneticfield design and strength (200-500 Gauss) on the total hardness with time as a function of precipitation of hardness saltsfrom water and scale formation.

Electromagnetic method for softening natural water

A water softening method was saggested. The optimal parameters of the external electric field were determined and apparatus for the implementation of the suggested method was described. The mechanism of the coagulation of hardness salts was studied.

Notes on the reproduction and survival of Moina hutchinsoni Brehm, 1937 (Moinidae: Anomopoda) grown in media of varying salinity

Moina hutchinsoni, a North American species distributed in saline and alkaline waters, was isolated from temporary puddles in the former Texcoco Lake basin near Mexico City. Its growth under laboratory conditions was assayed at different salinity values. Two culture media were tested: reconstituted hard-water plus sea salts and diluted natural brine. The alga Ankistrodesmus falcatus was supplied as food at a concentration of 0.4 x 106 cells ml-1. Salinity levels ranged from 2 to 20. For all experiments, twenty replicates, consisting of one neonate female individually placed in a glass container with 80 ml culture volume, were used. All vessels were reviewed daily and the progeny counted and removed. Culture media and food were renewed each day. Data on the survival and reproduction of M. hutchinsoni were recorded during its entire life cycle. The high average longevity (22.6) days, number of clutches (17.8), and average total progeny (138.9 neonates). were recorded at a salinity of 10 of natural brine water. In the synthetic medium reconstituted hard water plus sea salts, the highest average longevity 9.2 days, one of the highest number of clutches (9.6), and the highest average total progeny (29.5) neonates. were recorded at a salinity of 4. Reproduction and survival was affected by salinity and the culture medium, with the best results recorded in diluted natural brine. The information presented here is the first biological data surveyed for this euryhaline species in experimental conditions.

Effect of Discharge Fluctuation on Water Quality Variables from the Yeşilırmak River

Bu çalışmada Yeşilırmak Nehri sularının kalitesini etkileyen esas süreçleri belirlemek amacıyla debi ile su sıcaklığı, Na+, K+, Ca2++Mg2+, CO32-, HCO3-, Cl-, SO42- B, sodyum adsorpsiyon oranı SAR , su sertliği ve toplam tuz TS gibi değişik su kalitesi parametreleri arasındaki ilişki ve histerisis diyagramları incelenmektedir. Mevsimsel yağışlar, kar erimesi ve yüzey akış nedeniyle Mart, Nisan ve Mayıs ayları debinin en fazla olduğu dönemi temsil ederken en düşük akım Haziran ve Şubat ayları arasında gözlemlenmiştir. Çalışma sonuçlarına göre su kalitesi parametrelerinin çoğunluğu debinin düşük olduğu dönemlerde yüksek, debinin yüksek olduğu dönemlerde ise düşük değerlere sahip olup saat yelkovanı yönünde histerisisler sergilemektedir. Debi ile EC, Na+, K+, Ca2++Mg2+, HCO3-, Cl-, SO2-, SAR, su sertliği ve TS arasında ters yönde bir ilişki bulunmuştur. Buna karşın, debi ile su sıcaklığı, pH, CO32- ve B arasında bir ilişki bulunamamıştır. Su kalitesi parametrelerinden pH, Na+, K+, Cl- CO32-, SAR ve B karmaşık bir döngüye sahipken EC, Ca2++Mg2+, HCO3-, SO4, su sertliği ve TS saat yelkovanı yönünde bir döngü göstermektedir. Yalnızca su sıcaklığı saat yelkovanının tersi yönde bir döngü göstermektedir

Influence of Hardness Salts on the Effectiveness of Zinc-1 Hydroxyethylidene 1,1 Diphosphonic Acid (HEDP) Mixtures in Inhibiting the Corrosion of Mild Steel in Neutral Oxygen-Containing Solutions

Abstract This paper presents an electrochemical study of the effect of calcium salts on the corrosion inhibition of mild steel by zinc-1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) mixtures and compares the effect of calcium and zinc additions on the effectiveness of HEDP. The results are considered in terms of the nature, concentration, and stability of the solution species present, especially the metal-HEDP complex anions. Calcium addition showed some inhibition for the corrosion of mild steel, but it is much lower than for zinc. This is associated with the low stability of calcium complexes compared with ferrous complexes, which facilitates the displacement of calcium ions from their complexes by ferrous ions forming soluble, unprotective, ferrous complexes. The zinc-HEDP mixtures give effective inhibition at a zinc:HEDP molar ratio of 2:1 and are attributed to anodic inhibition by the 2:1 complex anion, Zn2H−1L−. This inhibition is significantly affected by the presence of sufficient-free phosphona...

INVESTIGATION: CAUSES OF FAILURES OF SPRINKLER HEADS DURING MAINTENANCE TESTING

Thousands of sprinkler heads, which have been sampled from in-service sprinkler systems, were tested by Fire Systems Group (FSG) of Industrial and Research Services (IRS) of CSIRO in accordance with the requirements of Australian Standard AS 1851: Part 3 (Maintenance of fire protection equipment - Automatic fire sprinkler systems) and SSL Test Specification FTS-123. During the course of this testing FSG investigated causes of test failures of the sprinkler head samples. The results of these investigations indicated that the main reasons for failure of used sprinkler heads were: adding sodium silicate (waterglass or egg preserver) to the system in order to overcome small leaks; intergranular corrosion of the lead-tinbismuth eutectic solder, which fastens together the two halves of the fusible link; extensive deposit of paint on the deflector and the glass bulb or fusible link; heavy build-up of dirt and debris on the frame, heat-sensitive element and deflector; adhesion of the orifice disc to its seat, due to glue-like deposits of corrosion product; and deep deposits of hardened sediment or heavy build-up of water hardness salts above the orifice disc. Language: en

Influence of Ion Accumulation on the Emulsion Stability and Performance of Semi-Synthetic Metalworking Fluids

The metalworking industry is one of the largest in the United States. Although metalworking fluids (MWFs) are ubiquitous in manufacturing as coolants and lubricants, these emulsified fluids have a significant environmental impact over their life cycle. Accordingly, it has become necessary to better understand emulsion destabilization mechanisms that lead to MWF deterioration and disposal so that MWF formulations can be designed for increased longevity. This paper investigates the impact of pH and a wide range of hard water salts on MWF emulsion stability. While expected trends from the emulsion science literature are observed, it is shown that MWF destabilization can lead to an increase in the microbial load that the MWF can sustain while only slightly improving manufacturing performance as measured by the tapping torque test. Experimental observations also indicate that these trends are strongly correlated with increased emulsion particle size, regardless of whether increased particle size is achieved by aging, by reductions in pH, or by the addition of hard water salts. In MWF systems, these conditions typically result from the accumulation of divalent and trivalent cations over time due to hard water additions and exposure to metal workpieces and tools. While MWFs are formulated with EDTA to avoid emulsion destabilization due to cation accumulation, it is shown that EDTA can be ineffective or highly inefficient for this purpose due to direct interactions between EDTA and the MWF emulsifier system. Given the ineffectiveness of EDTA and commonly utilized MWF emulsifier systems to maintain stable emulsion size in the presence of high concentrations of hard water salts, a more effective and environmentally preferable technological change to the MWF formulation design is proposed and successfully demonstrated.

Poly(sulfobetaine)s and corresponding cationic polymers. XI. Synthesis and aqueous solution properties of a cationic poly(methyl iodide quaternized ethyl vinyl ether/N,N-dimethylaminopropyl maleamidic acid) copolymer

A copolymer prepared by the copolymerization of ethyl vinyl ether and maleic anhydride underwent amidoacidation with N,N-dimethylaminopropylamine. The obtained ethyl vinyl ether/dimethylaminopropyl maleamidic acid copolymer was then reacted with methyl iodide to yield poly(methyl iodide quaternized ethyl vinyl ether/N,N′-dimethylaminopropyl maleamidic acid) (MIQEDMAPMA). The greatest difference from other polyelectrolytes was the carboxylic group on the polymer chain unit of MIQEDMAPMA. Its aqueous solution properties in various salts and at various pH values were studied by measurements of the reduced viscosity and intrinsic viscosity. The reduced viscosity and intrinsic viscosity of this cationic polyelectrolyte were related to the types and concentrations of the added salts. The tendency of the salt effect was similar to that of other polyelectrolytes; that is, soft salt anions were more easily bound to the quaternary ammonium (R4N+) of MIQEDMAPMA than hard salt anions. Some salt ions strongly attracted the quaternary ammonium of the cationic polymeric side chain for the agglomeration of the polymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2261–2269, 2003

Extraction of Hardness Salts from Water with Chemisorbents

Hardness salts are removed from water with different sorbents (fibre, granulated, and zeolites). It is shown that the filter lifetime is determined by the SEC, specific surface, and regenerative capacity of the sorbent. A hypothesis is advanced concerning the expediency of using fibre chemisorbents for removing hardness salts not only from drinking water but also from cooling water.

State of Miners' Health in Germany

Abstract Underground mining has a long tradition in Germany. While the mineral royalty created the basis for government mining inspectorates in the Middle Ages, the medical care of the miners and their families is also documented as early as 1225 in the Iglau Mining Act. In the last 20 to 30 years, iron ore mining has stopped in western Germany; only hard coal, salt, potassium, and clay are still mined underground, in addition to some isolated mining of rare minerals. The main activity consists of hard coal mining, with 100,000 miners underground in the Saar and Ruhr coalfields. In eastern Germany, uranium mining employed approximately 400,000 to 600,000 miners between 1945 and 1990. These mines are no longer active, but the high incidence of lung cancer in this mining population calls for specific medical supervision and care. The former copper mines of the Mansfeld area in eastern Germany have created similar health problems for the miners involved. The medical care of all German miners is regulated by ...

Polysulfobetaines and corresponding cationic polymers. VI. Synthesis and aqueous solution properties of cationic poly(methyl iodide quaternized acrylamide-N,N-dimethylaminopropylmaleimide copolymer) [poly(MIQADMAPM)

The copolymer prepared by copolymerizing with acrylamide and maleic anhydride was imidized with N,N-dimethylaminopropylamine. The obtained acrylamide-N,N-dimethylaminopropylmaleimide (ADMAPM) copolymer was then reacted with methyl iodide to yield a poly(methyl iodide quaternized acrylamide-N,N-dimethylaminopropylmaleimide) copolymer [poly(MIQADMAPM)]. Its aqueous solution properties were studied by measurements of reduced viscosity, intrinsic viscosity, and flocculation test in this study. The reduced viscosity and intrinsic viscosity of this cationic polyelectrolyte were related to the types and concentration of the added salt. Soft salt anions were more easily bound to the quaternary ammonium cation (R 4 N + ) of poly(MIQADMAPM) than were hard salt anions. Halide anions are hard anions ; consequently, hard cations were more easily attracted to halide anions and reduced the binding degree of halide anion on the quaternary ammonium group (R 4 N + ). The intrinsic viscosity behavior for cationic polyelectrolyte resulting from the electrostatic repulsive force of the polymer chain was contrasted with polyampholyte. The effect of various flocculants on flocculation in different pH values was accessed in this study.

Corrosion of mild steel in water

An apparatus is described for determining the corrosion behaviour of rotating metal specimens in test solutions having a range of oxygen concentrations. Long term tests (up to 150 days) have been carried out on steel specimens at temeratures between 5 and 90oC in triply-distilled water, solutions containing 35ppm chloride, Teddington tap water, and sea water. Oxygen concentrations have ranged from near deaerated to oxygen saturated. Corrosion behaviour can be broadly interpreted on the basis of competition between factors such as chloride and oxygen content of the test solutions and the presence of hardness salts.Increased chloride and oxygen content increased the mass loss of the specimens during the test period although a high concentration of oxygen in the absence of chloride ions passivated the surface of the steel. Hardness salts decreased the mass loss of the specimens.

Corrosion of mild steel in water

AbstractAn apparatus is described for determining the corrosion behaviour of rotating ( ≤ 2 Hz) metal specimens in test solutions having a range of dissolved oxygen concentrations. Long term tests (up to 150 days) have been carried out on steel specimens at temperatures between 5 and 90°C in triply distilled water, solutions containing 35 ppm Cl-, Teddington tap water, and sea water. Oxygen concentrations ranged from near deaerated (∼ 0·08 ppm O2) to oxygen saturated. Increased chloride and oxygen content increased the mass loss of the specimens during the test period, although a high concentration of oxygen in the absence of chloride ions passivated the surface of the steel. Hardness salts decreased the mass loss of the specimens.

Crystallization phenomena and the floatability of sylvine and hard salt

For various reasons, difficulties arise in the flotation of sylvinite and kieseritic hard salt, resulting in considerable quality losses in potash production. High carnallite amounts in the crude salt and as a consequence different MgCl 2 concentrations in the brine are the most important reasons for the difficulties. The aim of this study was to characterize the nature of the surface of sylvine in brines of different MgCl 2 concentrations, i.e. to prove the existence of time-dependent partial solution effects on the salt surface and/or of crystallization phenomena leading to the formation of new mineral phases as centres of selective adsorption of surface-active substances, and to examine the influence of these alterations on floatability. By means of a comparison between laboratory flotation results, adsorption measurements, radiotracer measurements, and measurements of adhesion forces as well as scanning electron microscopy investigations, it was shown that the problems in the kieseritic hard salt (Rossleben, Germany) are mainly caused by the so-called red variety of sylvine. The conclusions of these investigations are, firstly, that improvement of flotation characteristics is possible by conditioning the flotation feed in the brine for a period of time, depending on the MgCl 2 concentration, before the addition of reagents to the brine and before the floatation. Secondly, the flotation-improving effect of the clay depressant Amysed-W is caused by the interaction of this reagent with the red sylvine and with the collector Rofamin by forming an inclusion compound of Amysed-W with the amine.

Enhanced biodegradation of a hard bis-quaternary ammonium salt.

Bacterial strains with a high biodegradation potential were isolated from activated sludge. Their ability to decompose the hard bis-quaternary ammonium salt FB was determined by the method of chemical oxygen demand (COD) in a mineral medium, where the compound FB was the only source of carbon. The COD values were very low after 21 d and in the course of this period they reached zero level twice. The contribution of adsorption to decrease the COD value was small. The maximum COD decrease was accompanied by an increase of cell respiration. It is suggested that FB is effectively decomposed in spite of the fact that according to its structure it is a typical hard detergent.

Geochemical investigation of Potassium-Magnesium Chloride mineralization of Zechstein 2 salt, Mors Dome, Denmark

Solid-rich inclusions at 20°C of the Na-K-Mg-Cl-H2O system, found in euhedral quartz from the top of Zechstein 2 salt in the Mors dome, Denmark, were objects of microthermometrical investigation. The quartz crystals, all of the long prismatic, slender type, average length of 750 μm, are genetically closely connected to the intercalated clay in the deck halite Na2r. The inclusions are faceted negative crystals, crystallographically orientated with the host quartz. Carnallite (KMgCl3 ·6H2O) is the main daughter mineral, followed by tetrahydrate (MgCl2-4H2O) and minor sylvite (KCl). Halite (NaCl) is found as grains in suspension in the trapped solutions. The trapped solutions represent melts of carnallite or tetrahydrate saturated with NaCl. The concentrations range from 167 mol MgCl2 + 83 mol K2Cl2 +3 mol Na2Cl2 per 1000 mol H2O to 250 mol MgCl2 + 5 mol K2Cl2 + 0 mol Na2Cl2 per 1000 mol H2O, corresponding to salinities from 52 to 62 weight%. Melting temperatures measured, 170-185°C, and estimated pressures, 80-110 MPa, are minimum trapping values. In a few cases highly irregular, "dry" grains of carnallite, containing dissolved high-pressure gas, were observed to have been trapped. In this study it is shown that the melting temperature of carnallite in a closed space, where evaporation is prevented, depends on the prevailing pressure. It is also shown that high-pressure gas is dissolved in trapped grains of carnallite or halite, but not in the solutions. Finally, the results lead to the proposal of a model, related to time and space, of the metamorphism of an original carnallitic potash bed and subsequent K-Mg-Cl mineralization of the deck halite. The original paragenesis kieserite-halite-carnallite, sedimented in the deeper parts of the basin, was altered to the present kieseritic hard salt by means of progressive geothermal metamorphism from Upper Triassic to Lower Cretaceous. The hanging wall of the potash bed, the deck halite, was mineralized by the metamorphic solutions, squeezed out from the potash bed, possibly during the diapiric penetration phase in Upper Jurassic - Lower Cretaceous.

Engineering geological and safety technological aspects for the final disposal of in situ-consolidated radioactive waste in hard rock and salt formations

In connection with its research and development work the Gesellschaft fur Strahlen- und Umweltforschung mbH Munchen (GSF) has successfully developed and tested methods for the final disposal of low and medium radioactive waste in 200 litre containers at the Asse salt mine. The low radioactive waste (LLW) was disposed of in chambers using various methods. The medium radioactive waste (MLW) was transported in single radiation shielding containers of almost 9 t weight into the former rocksalt mine. Subsequently the 200 l containers were lowered into the storage chamber.