Soda Ash Production Research Articles

FTIR analysis of water structure and its significance in the flotation of sodium carbonate and sodium bicarbonate salts

Abstract The production of soda ash from trona resources (sodium sesquicarbonate, Na 2 CO 3 ·NaHCO 3 ·2H 2 O) has completely displaced the production of synthetic soda ash in the USA. Further, the utilization of other trona resources is under consideration in China, Turkey, etc. Recent research has been concerned with the development of flotation technology for the trona industry. In this regard studies on the flotation behavior of sodium carbonate salts: trona, sodium carbonate monohydrate and decahydrate, as well as the flotation behavior of sodium bicarbonate, are reported for both cationic (dodecyl ammonium hydrochloride) and anionic (sodium dodecyl sulfate) collectors. It has been found that strong flotation of sodium bicarbonate (NaHCO 3 ) can be achieved with 100% recovery, while the other sodium carbonate salts do not float well. These results have been explained by FTIR analysis of aqueous solutions of Na 2 CO 3 and NaHCO 3 in a range of concentrations from very dilute to saturated conditions. The changes in the shape of the O–H stretching band of water are correlated with the flotation behavior of Na 2 CO 3 salts and NaHCO 3 . In addition, the absorption band of the carbonate ion at ca. 1385 cm −1 is used to monitor its interactions with water and/or other ions in solution. The infrared results demonstrate that Na 2 CO 3 acts as a water structure maker, leading to an extensively hydrated surface that accounts for the poor flotation of most sodium carbonate salts. In contrast, NaHCO 3 does not have this characteristic and consequently complete flotation is possible with both cationic and anionic collectors. These results support the previous water structure analysis for soluble salt flotation of alkali halides and other oxyanion salts.

Decreases in pollutant loading from residual soda ash production waste

The attenuation of residual industrial loads of chloride (Cl-) and total ammonia (T-NH3) from Solvay waste bedsto Ninemile Creek, New York, and downstream polluted Onondaga Lake, is characterized and quantified based on fourteen years ofmonitoring following closure of a soda ash manufacturing facility. Concentrations of these constituents were monitored atleast bi-weekly at two sites on Ninemile Creek that bound the waste bed inputs, and at the mouths of the two other major tributaries to the lake, to quantify inputs from the industrial deposits and to place these residual loads in the perspective of contributions to total lake loading. Variations in the concentrations of these constituents in Ninemile Creek downstreamof the industrial inputs within individual years are well represented by a dilution model; i.e., linearity of concentrationversus inverse stream flow. A relatively uniform ratio of T-NH3 to Cl- has been maintained in the residual loading, about 0.42 g T-NH3 per kg Cl-. Substantial decreases (∼40%) in loading of these constituents fromthe waste beds to Ninemile Creek over the post-closure period are documented through shifts in the dilution model. As a result,the contribution of this source to the total lake loading has decreased from ∼45% to <30%. The estimated total residual Cl- load received from the waste beds since closure of the industry (∼1 million metric tons) corresponds to ∼1.6 yr of the full operating load of the industry before closure. The time required to reach a Cl- concentration goal for Ninemile Creek is considered, based onprojections of the post-closure trend.

New developments in the production of heavy soda-ash via compacting method

Sodium carbonate, also called soda, is mainly used in the glass industry, but also has its operative range in the chemical industry, i.e. for processing sodium phosphates, detergents and soaps. It is differentiated between light, calcined soda, which has a bulk weight of approx. 0.5 kg/l, and heavy soda with a bulk weight of 1.0–1.1 kg/l. One of the oldest methods for processing heavy soda from light soda is the monohydrate method, where by addition of water monohydrate is formed, from which subsequently, the crystal water is removed in a steam pipe calcining drum. As this method is very energy- and therefore cost-intensive, for reasons of reducing the operating costs in the last years, it was changed more and more to the method of compacting with subsequent crushing and following screening. However, due to mechanical screening, this method is limited to a minimum particle size of 200 μm. But as the international market demands today a multitude of particle sizes in the range between 75 and 1.180 μm and the particles have to be absolutely dust-free at the same time, a new method has been developed and turned into practice. In two plants of recent dates, with a capacity of 160.000 tons/year, the new demands of the market have been considered. The plant will be explained here in detail.

Recent changes in the level of Lake Abiyata, central main Ethiopian Rift

The spatial and temporal variations in the level of Lake Abiyata and controlling natural and manmade factors are presented. This study has been made by combining evidence from hydrometeorological and lake level records, water budget analyses, aerial photograph and satellite imagery interpretations, and numerical groundwater flow modelling. The most important components of the water balance of the lake are precipitation, river inflow and evaporation. The lake level has been fluctuating considerably over a wide range (by 6 m during the last 60 years) strongly controlled by the precipitation trends in the adjacent highlands. Climatic changes and consequent reduction in the surface water inputs have resulted in the reduction of its size. Recent abstraction of water for irrigation and soda ash production have drastically changed both the lake level and its hydrochemistry. This change appears to have grave environmental consequences on the fragile rift lacustrine ecosystem.

Wet calcining of trona (sodium sesquicarbonate) and bicarbonate in a mixed solvent

Trona ore is used in large amounts for the production of soda ash. A key step in this process is the conversion of trona (sodium sesquicarbonate: Na 2CO 3·NaHCO 3·2H 2O) into soda (sodium carbonate anhydrate: Na 2CO 3). Currently, this conversion is done industrially by calcining of the raw ore in rotary calciners at ca. 120°C or higher (Natural Soda Ash—Occurrences, Processing, and Use, Van Nostrand Reinhold, New York, 1991, p. 267). Trona can however be converted at lower temperatures by using a “wet calcining” technique. In this technique, trona is contacted with an organic or mixed organic-aqueous solvent at a conversion temperature that depends on the water activity of the used solvent. In pure ethylene glycol this temperature can be as low as 55°C. The conversion by “wet calcining” occurs very similar to that in the regular dry calcining process via a solid phase conversion. The anhydrate crystals form directly from the solid trona. This produces pseudomorphs (J. Chem. Eng. Data 8(3) (1963) 301), i.e. agglomerates of fine anhydrate crystals (1–10 μm). At high temperatures, dense, finely pored agglomerates are formed, while the outer shape of the agglomerate retains the prism shape of the trona crystal. At low conversion temperatures, loosely packed or even unstable agglomerates are found.

Evaporative crystallization of anhydrous sodium carbonate at atmospheric conditions

AbstractA new process for the production of superdense anhydrous soda ash uses a mixture of water and a high‐boiling second solvent to lower the transition point at which anhydrous (Na2CO3) and monohydrous sodium (Na2CO3·H2O) carbonate are in equilibrium to below the atmospheric boiling point. The stable conditions for anhydrate were first established by measuring the water activity in saturated mixtures of water and ethylene glycol. With the results, fed‐batch evaporative crystallization experiments were carried out. Both the water activity and the crystallization measurements showed that anhydrous soda was stable in boiling mixtures containing more than 22.5 wt. % ethylene glycol (on a salt‐free basis). A subsequent continuous evaporative crystallization experiment produced anhydrous soda ash with a bulk density of 1,550 kg/m3, which is substantially higher than that of any other atmospherically crystallized soda.

Vacuum consolidation of soda-ash tailings

The Solvay process, widely used in industrial production of soda ash, generates a large quantity of tailings. The tailings consist of fine solids suspended in alkaline water that remain in a loose state, causing environmental concerns. An alternative solution for the management of sodaash tailings is presented in this paper, that is, the use of a vacuum pre-loading technique to consolidate the tailings so that they can be used as a foundation material in industrial sites. This paper presents the procedure and results of vacuum pre-loading consolidation of soda-ash tailings in a field trial. A vacuum pressure of approximately 90 kPa was applied to a 45 × 45 m area to a depth of 8 m via prefabricated vertical drains. The results showed that after 66 days of vacuum pre-loading treatment, the water content of the soda-ash tailings was reduced by 12·3% to 42·4%. Also, densification was shown by changes in void ratio, unit weight and settlement. The tailings were consolidated to a material with the undrained shear strength ranging from 22·3 to 34·4 kPa, compared with the initial value of 7·1–14·5 kPa. The allowable bearing capacity of the tailings reached 120 kPa as tested from the static loading plate test. The vacuum pre-loading method has shown to be a fast, effective and economically feasible alternative for in situ consolidation of soda-ash tailings.

Effect if reduced salinity input on river stratification and dissolved oxygen

Changes in the occurrence, character, and longitudinal extent of salinity (S) stratification, and related impacts on dissolved oxygen (DO), in the Seneca and Oswego Rivers, NY, in response to the abatement of ionic pollution of inflowing Onondaga Lake, is documented. The analysis is based on vertical profiles of specific conductance and DO collected over a 20 km reach of the river system for several years before and after the closure of the source of the ionic pollution, a soda ash manufacturing facility. The S difference between the lake and the Seneca River decreased from about 2.6 to 0.7 parts per thousand (‰) following the closure; more than 50% of the continuing difference is associated with lingering ionic waste loading from soda ash production. The occurrence and longitudinal range of the S stratification phenomenon was, and continues to be, highly dependent on river flow. It is most strongly manifested when river flow is low. The occurrence, magnitude, and longtitudinal extent of S stratification have decreased, and vertical exchange between the stratified layers has increased, since the closure, thereby ameliorating the coupled negative impact on the river's oxygen resources. However, under low flow conditions (e.g., probability of occurrence equal to 15%) S stratification continues to extent > 2 km upstream and > 8 km downstream of the point of entry of Onondaga Lake into the Seneca River. Severe DO depletion in the lowel river layer, representing violations of New York water quality standards, continues to occur where S stratification prevails. Elimination of the continuing ionic waste inputs from soda ash production would further limit the stratification phenomenon and improve the river's DO problem.

Soda Ash Production from Trona in a Spray Dryer

Production of soda ash from Trona solution was achieved in a spray dryer reactor. Fractional conversion of NaHCO3 reached to values close to unity in this unit within a residence time of less than a second. Results indicated that above 140°C, heat transfer limitations played a significant role on the calcination process taking place in the spray dryer. Equilibrium limitations may become important only at very low temperatures and at high CO2 and H2O partial pressures. Results obtained in the spray dryer and from the thermal gravimetric analysis of Trona crystals agreed well. It was also shown that the predictions of the unreacted core model are in good agreement with the kinetic data. © 1997 SCI.

Soda Ash Production from Trona in a Spray Dryer

Soda Ash Production from Trona in a Spray Dryer

Density Stratification in Onondaga Lake: 1968–1994

ABSTRACT The profound impact of ionic (saline) waste from soda ash production on the density of inflows to, and the stratification regime of, Onondaga Lake, NY is documented. The analysis is based on inflow data reported by Effler et al. 1996 in this issue and on lake monitoring data collected over the 1968–1994 interval. Particular emphasis is placed on characterization of changes that followed closure of the soda ash manufacturing facility. Inflows enriched with the ionic waste have been more dense than the lake surface and entered as underflows, sometimes plunging to the lake bottom. Density differences have been reduced, but not eliminated, following closure of the facility. During the operation of the facility, the lake annually had a significant salinity component of density stratification, spring turnover failed to occur in a number of years, the duration of summer stratification was extended, and reformation of salinity-based stratification in fall was common. A nearly 90% reduction in ionic waste loading from soda ash production has substantially ameliorated these impacts, though some impact continues to be observed from the residual loading. The impacts of ionic waste on the lake's stratification regime have exacerbated the lake's problem of limited hypolimnetic oxygen resources.

SENSITIVITY ANALYSIS FOR TRONA SOLUTION MINING

Mineral Resources EngineeringVol. 04, No. 02, pp. 201-213 (1995) No AccessSENSITIVITY ANALYSIS FOR TRONA SOLUTION MININGG. NASÜN-SAYGILI and H. OKUTANG. NASÜN-SAYGILIIstanbul Technical University, Chemical and Metallurgical Faculty, Chemical Engineering Department, 80626 Maslak-Istanbul, Turkey Search for more papers by this author and H. OKUTANIstanbul Technical University, Chemical and Metallurgical Faculty, Chemical Engineering Department, 80626 Maslak-Istanbul, Turkey Search for more papers by this author https://doi.org/10.1142/S0950609895000199Cited by:0 PreviousNext AboutSectionsPDF/EPUB ToolsAdd to favoritesDownload CitationsTrack CitationsRecommend to Library ShareShare onFacebookTwitterLinked InRedditEmail AbstractDuring the past decade, solution mining of trona has emerged as a viable alternative to conventional mining technology applications. The significance of this production level becomes quite apparent for soda ash production after 1980’s. Areas of investigation of Turkish trona mineral have generally focused on leaching chemistry, solution flow characteristics and surface plant parameters. Economics of trona solution mining was investigated for Turkish trona deposit to offer comparative estimates of this method and conventional mining techniques. This study presents the results of an in-depth analysis of in situ trona production costs by employing a process engineering approach. This approach disaggregates the solution mining process and analyzes each component in terms of its requirements and associated costs. The cost model developed under this effort has been applied to typical solution mining situation encountered in Beypazari. Sensitivity tests were also conducted to identify the degree of cost influence exerted by incremental changes in key project parameters. The method considered here is alkali extraction method. FiguresReferencesRelatedDetails Recommended Vol. 04, No. 02 Metrics History PDF download

FMC introduces lower cost soda ash process

The board of directors of FMC, the largest U.S. producer of soda ash, has approved the first phase of a major project that the company says will significantly lower soda ash production costs at its Green River, Wyo., facility through use of a new proprietary manufacturing technology. A second phase of the project will increase production capacity at the facility. The key to the new system lies primarily in the mining of trona ore, which is processed to make soda ash, and in disposal of the tailings, or waste ore. Under the process, which is a modification of FMC's solution mining technique, spent ore is injected back into the trona mine and deposited in mined-out areas by the same water stream used to solution mine the virgin ore being brought up for processing. By redepositing inert tailings in the mine, above-ground tailings storage is not needed. Five patents cover key aspects of the new process: ...

The manufacture of soda ash in the Arabian Gulf

This paper is concerned with the technical and economic aspects of the soda ash production in the Arabian Gulf. Five different manufacturing methods are outlined. The two main manufacturing methods (the Solvay and Dual processes) are examined in detail. The technical aspects regarding the raw material quantitative and qualitative requirements, the battery limits plant production units and utility requirements are specified in each case. A preliminary economic evaluation of each of these two processing routs concludes that soda ash production by either route is competitive with imported soda ash assuming full marketability of soda ash and its by-products in the Arabian Gulf and neighbouring regions. The Solvay and Dual processes are estimated to produce soda ash at a cost of 132 and 144 $ /ton respectively. These production costs compare favourably against delivered costs of imported soda ash of 177 $/ton.

Pollutant loadings from solvay waste beds to lower Ninemile Creek, New York

Concentrations of Cl, total ammonia (TNH3), NO3 plus NO2, total P (TP), and soluble reactive P (SRP) were measured at two sites, located 5 km apart, on Ninemile Creek, New York, for a period of more than 8 mo. The sites bound the most recently formed Solvay waste beds, associated with the production of soda ash, that adjoin the creek. Concentrations of Cl and T-NH3 increased on average by factors of 16.1 and 7.6, respectively, over the monitored stream reach. The estimated average loadings of these materials to the stream over this reach were 2.3 × 105 and 1.2 × 102 kg d−1, respectively. These inputs are attributable to the Solvay waste beds. The loading of Cl from this source has not changed significantly over a 4 yr period since the closure of the soda ash manufacturing facility. This is the single largest source of Cl, and the second largest source of T-NH3, to polluted Onondaga Lake. Profiles of Cl in the lake indicated that at times the creek inflow plunges to subsurface layers as a result of its elevated density. This is at least in part a result of the creek's ionic enrichment. The concentration of SRP decreased by a factor of 2.0 on average over the study reach, probably due to adsorption to the CaCO3 deposits that cover the stream bed in this area. However, the TP load from the creek to the lake is not significantly affected by this phenomenon.

WHY HAVE LAKE ERIE CHLORIDE CONCENTRATIONS DECREASED?

Since the turn of the century, chloride concentrations in Lake Erie have risen from approximately 7 mg/L to approximately 35–45 mg/L in the late 1960’s. However, since the late 1960s, chloride concentrations have decreased to approximately 15–20 mg/L. In order to gain a quantitative understanding of this recent decreasing trend, this paper evaluates the available historical chloride loading data from the major industrial point sources along the Detroit River (which accounts for 94% of the inflow to Lake Erie). Since the 1960s five of the six major industrial point sources have either ceased the production of soda ash by the Solvay method or ceased the manufacture of various inorganic chemicals by chlor-alkali methods. This has resulted in a decrease in chloride loadings to the Detroit River of 4,680 tonnes/day. In 1967, this accounted for 53.5% of the total chloride loadings from Detroit River point and nonpoint sources and 36% of the total chloride input from the Detroit River to Lake Erie. The substantial reductions in chloride loadings resulting from these changes in industrial operations demonstrate the importance of process change when dealing with polluting substances which cannot be treated at a realistic cost.

THE CHLOR-ALKALI INDUSTRIES IN THE USSR

Spatial patterns in the production of chlor-alkali chemicals (soda ash, caustic soda, and chlorine) in the USSR are examined. The opening of large new salt deposits in the Volga region in the 1950s not only increased output of soda ash considerably, but also dramatically shifted production because of soda ash's raw material orientation. In contrast, because caustic-chlorine production tends to be market oriented, it was mainly the development of chlor-organic synthesis in the 1960s and 1970s that resulted in much greater spatial dispersion of production. Overall, the industry is now in a slow-growth phase, following the rapid gains made during the postwar period. Soda ash production is actually declining, while the wide array of applications for chlorine, especially chlorinated hydrocarbons, promises continued growth for the caustic-chlorine sector.

A Distributed Control System for the Soda Ash Production Plant Automation – Architecture, Software Design and Engineering

The paper presents the architecture, specialized software design and the engineering methodology for the control and optimization of the soda ash production plant in Devnia, Bulgaria.Soda ash is produced according to a bach process, based on the carbonization of ammonia brine with gaseous C02, filtration of the resulting bicarbonate suspension, which is followed by calcination of the bicarbonate in steam cal-cinators.In the paper are defined the two most important tasks as follows: 1. Control and optimization of the technological feeds, utilization and betterment of the conditions for optimized plant work. 2. Optimized control of the ratio of feeding gas (high and low pressure) to the carbonizing columns.The realization of these tasks is fulfiled by a distributed multifunctional microprocessor system of second generation with capabilities for closed-loop control, constraint control and data traffic via a common data bus. The dialogue between the system and the operator is realized by a specialized unit, including a colour display. On the basis of a detailed study of the process technology and the used standard algorithms a hierarchical supervisory approach is developed, including control of the setpoints of the existing conventional controllers and complicated logical and mathematical workouts.With the solution of the formulated tasks was assured optimum operation of the carbonizing columns and significant economical and social benefits were obtained.

Materials of construction for plate heat exchangers in soda ash production

Materials of construction for plate heat exchangers in soda ash production

TGS Maps Entry into Soda Ash Production

TGS Maps Entry into Soda Ash Production