Applikationer

Determination of lithium, sodium, ammonium, potassium, calcium, magnesium, and strontium in brine using cation chromatography with direct conductivity detection.

Sample dilution is a work-intensive routine task in the analysis laboratory. An automatic two-step dilution exponentiates the dilution factor – 1:100 – thus incorporating a dilution factor of 10,000. The intelligent dilution is made possible by MagIC Net, which calculates the essential dilution steps, and by the dosing properties of the 800 Dosino and the Liquid Handling Station. The Application Note shows statistical results of a 1:10,000 dilution.

As a rule, brine samples are diluted extremely in order to avoid overloading the column. Manual dilution is very error-prone, which is why this application relies on injection with a 0.25 µL internal loop, thus saving an additional dilution step. Sodium, potassium, magnesium and calcium in brine are determined on a Metrosep C 6 - 150/4.0 column with subsequent direct conductivity detection.

Determination of the sulfate content of brines.

Determination of sodium in seawater and similar brines. This procedure is suitable for the analysis of sodium in seawater contaminated with sodium aluminate solutions emanating from alumina refineries, and seawater which has been used for the neutralization of alumina refinery waste («red mud») slurries.

Determination of total halides (Cl- + Br- +I-) in seawater and similar brines. This procedure is suitable for the analysis of total halides in seawater contaminated with sodium aluminate solutions emanating from alumina refineries, and seawater which has been used for the neutralization of alumina refinery waste («red mud») slurries. Given the small concentration of bromine andiodine in seawater, the total halide content approximates the chloride concentration.

In this Process Application Note, the analysis of low concentrations of calcium and magnesium (0–20 µg/L) in brine is addressed. The presence of calcium and magnesium can shorten the performance and lifetime of the membranes used in the chlor-alkali industry for the production of chlorine. Accurate online monitoring of the hardness is needed in several stages of the process. Other parameters such as acidity, carbonate, hydroxide, silica, alumina, ammonia, iodate and chlorine can also be analyzed online.

In the Solvay process, ammonium hydrogen carbonate and table salt are converted to sodium hydrogen carbonate and ammonium chloride. Heating the former yields sodium carbonate (soda), an important raw material for the soap and glass industries. Ammonia is an incipient and is regenerated almost completely through conversion of the ammonium chloride with lime milk (Ca(OH)2).A Metrohm process analyzer monitors the ammonia content in the saturated table salt solution after absorption tower, thus guaranteeing a good product yield in the carbonization tower. Additional parameters which can be determined with the analyzer in the Solvay process include: alkalinity, carbonate, chloride, calcium oxide and carbon dioxide.

Lithium is a soft alkali metal that is typically obtained from salt lake brines. Lithium is used for many applications, but especially for production of lithium-ion batteries in electric cars, mobile phones, and more. This Process Application Note presents a method to monitor lithium as well as other cations in brines by online process ion chromatography (IC), a multiparameter analytical technique that can measure ionic analytes in a wide range of concentrations.

This Process Application Note describes a method to determine the strontium and barium concentration in brine as early detectors ofmembrane fouling via online process ion chromatography. Using this multiparameter analytical technique can help reduce the risk of premature membrane fouling and avoid unexpected maintenance and high utility costs with 24/7 automated analysis.

Determination of bromide and sulfate in brine (300 g/L NaCl) using anion chromatography with conductivity detection after chemical suppression.

Determination of chlorate and sulfate in a brine solution (1.5% NaCl) using anion chromatography with conductivity detection after chemical suppression.

The anion column Metrosep A Supp 15 - 150/4.0 is a pretty high-capacity column. The direct determination of arsenate in a matrix of 180 mg/L chloride and 320 mg/L sulfate is not possible, as the arsenate is hardly detectable under the sulfate peak tail. Sample reinjection cuts off the majority of the matrix and therefore allows an accurate determination of the arsenate.

Determination of sulfate in brine by indirect potentiometric titration with EGTA using platinum and tungsten electrodes.

Determination of traces of calcium in brine by photometric titration with 1,2-diaminocyclohexanetetraacetic acid using the 610 nm Spectrode.

Alkalinity is well-suited as a means of describing the capacity of a body of water to neutralize acid contaminations. It is therefore an important indicator for estimating the influence of contaminations on the ecological system.

Lithium is a soft metal which is used for many applications, such as production of high-temperature lubricants or heat-resistant glass. Furthermore, lithium is used in large quantities in for battery production. It is obtained from brines and high-grade lithium ores. Depending on the lithium concentration, extraction may or may not be economically viable.This Application Note demonstrates a method to determine the lithium concentration in brines by potentiometric titration. Lithium and fluoride precipitate in ethanol as insoluble lithium fluoride. Using ammonium fluoride as the titrant and a fluoride ion-selective electrode (ISE), determination via potentiometric titration is possible. This method is more reliable, faster, and less expensive than the determination of lithium in brine by other more sophisticated techniques such as atomic absorption spectroscopy (AAS).

Determination of Cd, Pb, and Cu in brine and NaOH.

It is crucial to monitor iodide in NaCl brine to prevent membrane fouling during chlor-alkali electrolysis. Stripping voltammetry offers precise iodide analysis.

Chlorine and caustic soda are used as feedstock materials in myriad production processes for several markets including pulp and paper, petrochem, and pharma. The chlor-alkali process, accounting for 95% of production, depends on the electrolysis of brine, which first requires several steps of purification. This white paper describes the reasoning and benefits for online and inline process analysis over conventional methods for the production of these basic chemicals.

Ion measurement can be conducted in several different ways, e.g., ion chromatography (IC), inductively coupled plasma optical emission spectrometry (ICP-OES), or atom absorption spectroscopy (AAS). Each of these are well-established, widely used methods in analytical laboratories. However, the initial costs are relatively high. In contrast, ion measurement by the use of an ion-selective electrode (ISE) is a promising alternative to these costly techniques. This White Paper explains the challenges which may be encountered when applying standard addition or direct measurement, and how to overcome them in order for analysts to gain more confidence with this type of analysis.