Removal of Hardness from Water Samples by a Carbonation Process with a Closed Pressure Reactor

One of the undesirable characteristics of some ground and natural water sources is hardness. Hard water can cause many problems around the world, including increased scaling on water pipes, boilers, atopic eczema and odd-tasting drinking water. Hardness in natural water is caused by dissolved minerals, mainly calcium and magnesium compounds. According to the Water Quality Association (WQA) and the United States Geological Survey (USGS), hard water is classified based on the Ca2+ and Mg2+ ion concentration in waters, as follows: 0–60 ppm as soft; 61–120 ppm as moderately hard; 121–180 ppm as hard and more than 180 ppm as very hard water. Most water utilities consider a hardness level between 50 and 150 ppm of CaCO3 as publicly acceptable. The present study investigated the effects of a carbonation process on the removal of hardness in different water samples. Currently, a wide variety of hardness removal technologies are available. Among those conventional methods, carbonation is an inexpensive process which can be used for the removal of Ca2+ and Mg2+ ions from hard water. This study measured the hardness levels of 17 different water samples using the ethylene diamine tetra acetic acid (EDTA) method. Among these, Seoul outdoor swimming pool water (140 ppm) samples showed high concentrations of Ca2+ and Mg2+ ions. The hardness of the different water samples was reduced by 40–85% by a carbonation process with a closed pressure reactor for a 5 min reaction time

Effect of water content on accelerated carbonation of municipal solid waste incinerator bottom ash for CO2 capture

For comparison of different water-to-solid ratio for the accelerated carbonation of municipal solid waste incinerator (MSWI) bottom ash for CO2 capture, it is necessary to understand the morphological changes of bottom ash as a carbonation reaction. Only the water-to-solid ratio (W/S) at atmospheric pressure was controlled from 0.3 to 10 dm3/kg and the CO2 concentration was kept constant at 30% while the reaction temperature was held at 20oC. The result of an XRD analysis indicated that portlandite, ettringite,and hydrocalumite in untreated bottom ash could combine with CO2 to form mainly an amorphous Al-material and calcite. In the case of 10 W/S, the amount of CO2 reacted with bottom ash approached the maximum value after 120 min reaction time, whereas the reaction at 0.3 S/W was scarcely carbonated after 60 min because of encapsulation effect

Aragonite precipitated calcium carbonate : A new kind of functional filler

This article ascribes an exclusive overview of the synthesized aragonite precipitated calcium carbonate and its applications in various fields. Special attention is given on aragonite pcc is a new kind of functional filler in the paper industry and automotive industry. Now a days, aragonite pcc synthesis is the most exciting and important industrial application process. Aragonite pcc is an interesting and attractive mineral for its unique characteristic features and enhances the preselected properties of paper like opacity, density and brightness etc. The new rising acicular type of aragonite pcc mineral, in particular is being used as filler for polyolefin resins and polypropylene composites which are significantly used in automobile industry to manufacture light weight vehicles

Scalenohedral calcite crystal growth by carbonation process for CO2 sequestration

The objective of the present research work is to intensify the CO2 sequestration process via carbonation process to improve yield and kinetics in the formation of the scalenohedral calcite polymorph of calcium carbonate, which has some valuable applications in paper industry. In the present work, we have synthesized a novel microstructure of scalenohedral calcite by a simple and eco - friendly carbonation process and it has been carried out in liquid-gas system. Various parameters such as temperature,CO2 flow rates and the total volume concentration were investigated to enhance the sensitivity of the process. The highest average length of the scalenohedral calcite was obtained at pH 6.0, temperature 450C, Ca(OH)2concentration 0.2M, CO2 flow rate 80mL/ min and the total volume 1L. The synthesized calcite was characterized by XRD and SEM to identify the phases and surface morphology. The scalenohedral calcite was applied successfully as filler to improve the optical properties of waste paper recycling of the hand sheets (old newspaper, ONP)

Extraction of rare earth metals (REMs) from chloride medium by organo-metallic complexation using D2EHPA

Present report delt with the studies on complexation of rare earth metals (REMs) present in chloride leach liquor of monazite with phosphoric extractant, di-2-ethylhexyl phosphoric acid (D2EHPA). Further, the co-ordination chemistry was studied by determining the complex formation, its structure and validation with standard mathematical model equation. The systematic solvent extraction complexation studies were carried out using 5% D2EHPA diluted in kerosene and mixed with 1% isodecanol (modifier) to form organometallic complex during extraction. After optimizing various process parameters, it was observed that a good separation factors of 17.73 for Nd/La at pH 2 and 12.69 for Pr/La at pH 1.7 were obtained. The value for log D and slope analysis were found 3 as per the expected complex formation (M3+ + 3HA = MA3 + 3H+). Mc-Cabe Thiele plots indicated the requirement of mostly ∼3 for REMs extraction. The result will be helpful to set multi stage mixer settler unit (MSU) for the recovery of pure solution of individual/mixed rare earth solution. Based on the results of basic scientific studies, the complex formation and number of stage required for the mixer settler units (MSU) in continuous operation in commercial plant can be determined and accordingly designed