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Pag. 13
Purification and characterization of reagent grade NaCl obtained from
Crucita seawater
Purificación y caracterización de NaCl grado reactivo obtenido del agua de mar de Crucita
Antonella Ferrin
1
* ; Thalía Caicedo
2
; Segundo García
3
; Ramón Cevallos
4
& Ariana García
5
Received: 05/07/2024 – Accepted: 12/10/2024 – Published: 01/01/2025
Research
Articles
X
Review
Articles
Essay
Articles
* Author for correspondence.
Abstract
The main objective of this work is to analyze and apply the processes to obtain sodium chloride (NaCl) in a seawater sample form Crucita-Manabí and
bring it to a higher purity in accordance with the Pharmacopoeia standards of the United States (USP). USP establishes quality standards and specifications
for a wide range of pharmaceutical, chemical and health products. Therefore, the research was developed in three stages: the first corresponded to the
purification of NaCl through the compilation of information from bibliographic sources that allowed investigating the different industrial and artisanal
processes for the purification of NaCl, through this research it was possible to determine that to carry out this process separation, crystallization, distillation
and filtration techniques were applied that allow the elimination of impurities present in the sample. The second stage corresponded to the analysis
established based on the results obtained in the purification process; Therefore, it was essential to evaluate the conditions that allowed the impurities
present to be eliminated, making it necessary to perform physical and chemical tests to determine the percentage of purity of the final product. Finally,
the third stage consisted of analyzing the final product to establish whether it met the proposed objective based on the USP regulations on NaCl.
Solo25&%
Keywords
Sodium Chloride, Purification, Crystallization, Distillation, Filtration.
Resumen
El presente trabajo, tiene como objetivo principal analizar y aplicar los procesos para la obtención del cloruro de sodio (NaCl) grado reactivo en muestra
de agua de mar de Crucita-Manabí y llevarlo a una pureza más elevada acorde a los estándares de Farmacopea de los Estados Unidos (USP, por sus siglas
en inglés). La USP establece estándares y especificaciones de calidad para una amplia gama de productos farmacéuticos, químicos y de salud. Por tanto,
la investigación se desarrolló en tres etapas: la primera correspondió a la purificación del NaCl a través de la recopilación de información de fuentes
bibliográficas que permitieron poder analizar los diferentes procesos industriales y artesanales para la purificación del NaCl, mediante esta investigación
se pudo determinar que para llevar a cabo este proceso se aplicaron técnicas de separación, cristalización, destilación y filtración que permiten la
eliminación de impurezas presentes en la muestra. La segunda etapa, correspondió al análisis establecido en base a los resultados obtenidos en el proceso
de purificación; por tanto, fue fundamental evaluar las condiciones que permitieron eliminar las impurezas presentes, siendo necesario realizar pruebas
físicas y químicas para determinar el porcentaje de pureza del producto final. Finalmente, la tercera etapa consistió en analizar el producto final para
establecer si este cumplía con el objetivo propuesto basado en las normativas USP sobre el NaCl.
Palabras clave
Cloruro de Sodio, Purificación, Cristalización, Destilación, Filtración.
1. Introduction
NaCl is a simple chemical compound, composed of a
sodium ion (Na+) and a chlorine ion (Cl-), known as
common or table salt; it is a crystalline solid and soluble in
water [1].
Reactive sodium chloride is a purified and superior variant
of the conventionally used NaCl. This NaCl is used in
laboratories and industries that demand a higher level of
purity than that offered by common salt. For its use, reactive
NaCl must meet specific purity requirements (99% -
100.5%) according to USP standards and be free of
impurities that could affect the chemical or biological
processes in which it is applied.
1
Universidad Técnica De Manabí. https://orcid.org/0009-0007-5012-0632 , mferrin4180@utm.edu.ec ; Portoviejo; Ecuador.
2
Universidad Técnica De Manabí. https://orcid.org/0009-0001-7103-9434 , tcaicedo6535@utm.edu.ec ; Portoviejo; Ecuador.
3
Universidad Técnica De Manabí. https://orcid.org/0000-0002-8152-3406 , segundo.garcia@utm.edu.ec ; Portoviejo; Ecuador.
4
Universidad Técnica De Manabí. https://orcid.org/0000-0002-8583-4674 , ramon.cevallos@utm.edu.ec ; Portoviejo; Ecuador.
5
Universidad Técnica De Manabí. https://orcid.org/0000-0001-6893-0843 , agarcia4908@utm.edu.ec ; Portoviejo; Ecuador.
This compound has a wide application in sectors such as the
chemical and pharmaceutical industry, where it is used as a
reagent, buffering agent and in the production of various
chemical products. It is also used in scientific research and
in the production of food, medicines and cosmetics.
The present research focused on obtaining reagent grade
NaCl in Ecuador, the purpose was to obtain this product and
bring it to the highest possible purity since the process and
purification of this product has not been done before in the
country despite having enough raw material available, and
to study and analyze the theoretical principles behind the
NaCl purification process, including physical analysis and
the chemical reactions involved.
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Pag. 14
Manabí is a province with saline resources that are used for
salt production; however, at present the national industry
does not produce NaCl for reactive use and proof of this is
that the country's universities are forced to acquire NaCl in
its reactive grade from chemical companies that import it
for use in various analyses or studies carried out in
laboratories at the university level. In this sense, it is
necessary to carry out an investigation on the NaCl
purification process and analyze it in seawater samples from
Crucita-Manabí to determine its purity level and bring it to
a higher purity according to the mentioned standards.
For this, a punctual sampling of the water was carried out in
which representative samples were obtained and physical-
chemical analyses were carried out to determine the
concentration of NaCl before and after the purification
process and then analyze the purity of the NaCl obtained by
the simple evaporation method, evaluating the effectiveness
of the process and comparing the results obtained with the
USP standards. The conditions to eliminate the impurities
present in the NaCl obtained were evaluated [1].
2. Materials and methods.
Before the composition of matter was discovered, the word
salt referred to any soluble, non-flammable solid, especially
when referring to that which was formed as a result of the
evaporation of seawater. Despite its ancient etymology, the
word salt is still used today with two distinct meanings. One
is the specific name of the chemical compound sodium
chloride, while the other is the generic name of the group of
chemical substances formed from acids in which metals
have partially or completely replaced hydrogen atoms [2].
The salt purification process begins with brine deionization
or evaporation, where the ions are treated to remove
impurities and sometimes purified before crystallization. It
occurs in open-air salt pans that favor sodium chloride
crystallization when evaporation begins [1].
A new technique to purify sodium chloride is by two-
dimensional gel electrophoresis. The technique allows
obtaining NaCl nanoparticles uniform in size and of high
purity, which could be used in a variety of areas such as
medicine and catalysis [3]. In the present work, a study was
conducted that analyzed how operational parameters affect
the purification of NaCl by ultrasound-assisted
crystallization. The results showed that this technique can
produce high purity NaCl crystals with lower energy
consumption than conventional techniques [4]. A very
novel technique was found to account for the use of
modified zeolites as adsorbents to purify NaCl from
wastewater. The technique allowed the recovery of high
purity NaCl while reducing the impact of wastewater effect
on the environment [5]. Similarly, purification of reactive
NaCl by evaporation, simple distillation and ion exchange
was performed.
The detailed process for obtaining reagent grade NaCl from
seawater is described below. The method employed
involves a series of successive stages, including initial
physical-chemical analysis, evaporation, recrystallization,
dissolution, filtration, distillation, ion exchange, washing of
crystals and finally drying. The NaCl obtained was
characterized by physicochemical analysis to determine
purity, reaching a classification that is considered reactive.
The initial sampling and analysis consisted of collecting 20
liters of seawater and performing initial physical and
chemical analyses to determine the characteristics of the
seawater. Then, precipitation and primary crystallization
were performed, which consisted of evaporating 12 liters of
seawater at 100ºC for 8 hours. Evaporation caused the
precipitation of dissolved chemical compounds, resulting in
primary crystallization; 500 ml of distilled water were
added to dilute the sample, and then vacuum filtration was
performed to eliminate the non-soluble solids that
precipitated as the temperature increased. Next, distillation
and softening were carried out in which a simple distillation
was implemented to obtain a concentrated brine which was
analyzed detecting a high hardness in which an ion
exchange was applied using a cationic resin to eliminate
calcium and magnesium ions.
After this, fractional recrystallization and washing was
applied, where the brine was diluted again with 500 ml of
distilled water, evaporated at 100ºC for 10 minutes with
constant agitation, the solution was passed through columns
of regenerated cationic resin to eliminate the calcium and
magnesium ions (repeated 3 times), Evaporation was
carried out to obtain a fractional recrystallization, the
crystals were washed with 500 ml of additional distilled
water applying once again a new vacuum distillation and the
evaporation and recrystallization stage was repeated.
Finally, the drying and final analysis was carried out, which
consisted of taking the sample obtained to an oven at 105ºC
for 5 hours. Once the sample was dry, it was weighed and
562.45 g of NaCl was obtained, and finally, to determine its
percentage of purity, physical-chemical analysis was
carried out, where 97.23% of NaCl GR was obtained.
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Pag. 15
Fig. 1. Reagent-grade NaCl purification process flow diagram
2.1. Composition of seawater.
Seawater is a solution in water (H_2 O) of many different
substances. Up to 2/3 of the natural chemical elements are
present in seawater, although most of them only as traces.
Six components, all of them ions, account for more than
99% of the solute composition [6].
Table 1. Percentage composition of solid solutes in
seawater.
Anions
%
Cations
%
Chlorides
55,07
Sodium
30,62
Sulfates
7,72
Magnesium
3,68
Bicarbonates
(
)
0,41
Calcium
1,18
Bromide
0,19
Potassium
1,14
Fluorine
0,01
Strontium
0,02
Source: Osorio Arias & Álvarez Silva, 2006.
Information was gathered that allowed us to broaden our
knowledge about the different methods and techniques that
can be used in the process of obtaining NaCl Reactive
Grade.
2.2. Selection of raw material
The seawater selected for the extraction of NaCl G.R. was
collected in the sea of Crucita in the canton of Portoviejo,
province of Manabí, Ecuador (Fig. 1). These samples were
transferred to the chemistry laboratory of the Faculty of
Engineering and Applied Sciences.
Fig. 2. Panoramic view of the sea locality of Crucita.
2.3. Experimentation
The experimental work began by taking seawater samples
from the parish of Crucita for their respective physical-
chemical characterization in the aforementioned laboratory.
Physical-chemical analysis: alkalinity, chlorides,
conductivity, hardness, salinity, total solids, pH and
temperature.
RAW MATERIAL
PROCUREMENT
ANALYSIS
OF THE
SAMPLE
OBTAINED
Yes
CRYSTALLIZATION
WITH
EVAPORATION
No
SAMPLE ANALYSIS
AFTER
CRYSTALLIZATION
DISSOLUTION
AND FILTRATION
GLASS
WASHING
DISSOLUTION
AND SECOND
FILTRATION
DEIONIZATION
WITH CATIONIC
RESIN
ADDITIONAL
PURIFICATION AND
RECRYSTALLIZATION
RECRYSTALLIZATION
PURITY CHECK
WAREHOUSING
EVAPORATED
WATER
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Pag. 16
Table 2. Physical and chemical analysis of seawater
samples.
Components
Results
Units
Alkalinity
96
mg/L
Chlorides
20020
mg/L
Conductivity
64000
us/cm
Hardness
4764
mg/L
Salinity
0,14
%
Total Solids
1380
mg/L
pH
6,27
Temperature
27.5
ºC
The main methods applied during the experimentation were
gravimetric and volumetric: in the volumetric method the
ion contained in a given product was determined
quantitatively; by measuring the volume of a solution of
known concentration or standard solution that reacts with a
known amount of solution containing the element under
study and gravimetric method which is based on the precise
and accurate measurement of the mass to be determined,
which was separated from the rest of the components of the
sample being NaCl. Although most of the substances were
found in very low concentration, there were two important
substances that are commercially extracted from seawater:
sodium chloride (table salt) and magnesium [7].
The different physical analyses of the water sampled were
obtained using the multi-parameter equipment (BLE-9909).
Alkalinity: The alkalinity of seawater plays a crucial role in
buffering the pH of the ocean against acidification caused
by CO2. The alkalinity of seawater is mainly determined by
two components: carbonate ions and borate ions. These ions
neutralize the hydrogen ions produced by CO2 dissolution,
which limits the decrease in pH [8].
Alkalinity consists of the ability to neutralize acids and is
the sum of all titratable bases, it prevents water pH levels
from becoming too acidic or basic, giving rise to carbonates
and bicarbonates in seawater [9].
Fig. 3. Origen de bicarbonato y carbonato en el ambiente marino.
Hardness: Although seawater is an essential resource for life
on earth, its high salinity and hardness prevent it from being
used for human consumption or agricultural irrigation. The
removal of salt from seawater, or desalination process, has
become an increasingly important technology. The ability
of seawater to dissolve a soap is measured in terms of
because of its hardness. The presence of magnesium and
calcium ions is the main cause. The hardness of seawater in
the Pacific Ocean ranges from 200 to 400 mg/L CaCO3,
with higher values in coastal areas and lower values in the
open ocean [10]. Hardness can be temporary or permanent;
the water may contain calcium and magnesium bicarbonate,
iron or magnesium. It is characterized because its softening
is achieved by boiling, which consists of the bicarbonate
precipitating, releasing carbon dioxide and lowering the pH
value by carbonic acid formations [11].
The analysis of total hardness by titration with EDTA
(ethylenediaminetetraacetic acid), allowing the
quantification of Ca and Mg ions and their subsequent
conversion to total hardness expressed as CaCO3 was
carried out as follows:
10 ml of the sample water was taken in a flask, 1 ml of
Buffer solution pH 10 was added and as an indicator a pinch
of eriochrome black T (ENT) was used, the same which is
intended to form a purple colored mixture; to proceed to
titrate with EDTA; until the appearance of blue color.
Reactions:
Ca
+2
+ Mg
+2
+ Buffer pH10
Ca
+2
+ Mg
+2
+ ENT (Ca
-
Mg
-
ENT) purpura
(Ca
-
Mg
-
ENT) + EDTA (Ca
-
Mg
-
EDTA) + ENT
During the titration 56.2 ml of 0.01M EDTA were
consumed, where 53.5 ml corresponded to MgCO3 and 2.7
ml for CaCO3.
Calcium hardness: With the Buffer pH 10 the total
concentration of the sample hardness such as Ca and Mg
was determined. To determine the concentration of calcium
present in the sample, 1 ml of Buffer pH 10 was added to
the sample and then 20 drops of KOH were added to
regulate the pH 10 to pH 12. From this result, the total
hardness was subtracted to obtain the Mg concentration
value.
Consumption = 2,7 ml de EDTA 0,01M en CaCO
3.
Consumption = 53,5 ml de EDTA 0,01M en MgCO
3
.
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Pag. 17
Total hardness: 4764 mg/L - Calcium hardness: 270 mg/L=
4494 mg/L of Mg
MgCO3 = 4494 mg/L
It was determined that the hardness present in the sample
was found in higher percentage in Mg.
Sulfates (SO4-2): With an average concentration of about
2.7 g/L, sulfate is one of the most present inorganic anions
in seawater. It plays an important role in seawater chemistry
and has a major impact on marine life. The complex process
of sulfate cycling in the Pacific Ocean involves a variety of
physical, chemical and biological interactions [12]. Sulfates
are minerals whose structural unit is (SO4-2) groups,
cations of Al, Na, Ca, K, Mg, Fe, and others can be bonded
to sulfates. Among them are anhydrite and gypsum, which
are quite common in the earth's crust [13].
Table 3. Absorbance and concentration data for sulfate
Absorbance
Concentration
280,904
0,481
281,455
0,486
284,789
0,487
Fig. 4. Sulfate ion calibration curve.
The linearity obtained experimentally in the calibration
curve for the sulfate ion shows a correlation coefficient
r2=0.991 (Fig. 3). The curve was prepared with five
concentration levels and a blank in the concentration range
48,000-312,000 ppm.
Chlorides: With an average concentration of about 19.4 g/L,
chloride is the most present inorganic anion in seawater. It
plays a fundamental role in seawater chemistry with great
impact on marine life. The chloride cycle in the Pacific
Ocean is a complex process involving a series of
interactions [14].
Its analysis and concentration determination can be
performed by several methods; in the present work, Mohr's
method was used, which involves the quantitative
determination of chloride, bromide or cyanide ions by
titration with a standard solution of silver nitrate using
Na2CrO4 or K as endpoint chemical indicator [15].
5 ml was taken and diluted in 95 ml of distilled water; from
this dilution, 10 ml was used, 3 drops of K2CrO4 was added
as end point indicator because AgCl is less soluble than
Ag2CrO4 since the latter cannot be formed until Cl is fully
reacted. There are three ways to determine the end point of
the reaction: when a precipitate is produced, color change
and disappearance of turbidity.
When the color change occurred, the titrant AgNO3 made a
consumption of 20 ml, then the chloride calculation was
performed:
100 ml M ------------ 2,002 g Cl
-1
1000 ml M ----------- x = 20,02 g Cl
-1
Interpretation:
For every 100 ml of sample there was 2.002g Cl-1.
Sodium chloride (NaCl) extraction: Water is a liquid,
odorless, colorless and tasteless; it has a bluish tint and can
only be detected in very deep layers. At atmospheric
pressure, the freezing point of water is 0°C and the boiling
point is 100°C. Water reaches its maximum density at 4°C
and expands as it freezes, thus reducing its density, the same
happens when the temperature increases from 4°C [16].
The evaporation of the water that was applied in the NaCl
extraction process was that of the boiling point, in which 12
L of sea water was evaporated (fig.4); in the course of hours;
forming a first crystallization.
0,48
0,482
0,484
0,486
0,488
280 281 282 283 284 285
Sulfatos
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Pag. 18
Fig. 5. Evaporation process.
Subsequently, NaCl was dissolved in distilled water to
separate the insoluble solids that precipitated during the
evaporation process; a vacuum filtration process was
applied to this solution.
Vacuum filtration: is an instrumental technique used in
laboratories to separate solids from liquids or solutions.
This type of filtration is used when solids are of interest or
when gravity filtration is very slow; it is also an essential
technique in recrystallization processes [17].
Recrystallization: is a common purification technique for
NaCl, where an impure NaCl solution is dissolved in a
suitable solvent, allowed to evaporate slowly to increase the
NaCl concentration and then induce the precipitation of
pure crystals. The study of Li et al. (2023) proposes a new
NaCl recrystallization process by controlled evaporation
which consists of optimized control system and optimized
vessel design [18]. It was performed by simple distillation
(Fig. 5); this is the most widely used procedure for the
separation and purification of liquids, and it is the one that
is always performed aiming to separate a liquid from its
impurities [19].
Fig. 6. Simple distillation process.
When the first recrystallization was obtained, we proceeded
to perform the analysis of chlorides to determine the
percentage of purity of the sample obtained; here we
dissolved 0.5 g of sample with humidity in 95 ml of distilled
water, obtaining the following calculation:
100 ml ----------- 8,413g NaCl
1000 ml -----------x = 84,13g NaCl
Obtaining a purity of 84.13% of NaCl.
Ion exchange: According to Degremont (1979), ion
exchange is a reversible chemical reaction that takes place
when an ion in a solution is exchanged for another ion of
the same sign that is reattached to an immobile solid
particle. Ion exchangers are a process that consists of taking
advantage of the ability of resins to exchange ions between
a solid phase and a liquid phase in a reversible way, that is
to say that it returns to its original state and without
permanent change in the structure of the solid. Generally,
the great usefulness of ion exchange lies in the fact that ion
exchange materials can be used over and over again since
the exchanger material can be regenerated as the change it
undergoes in the 'operation phase' is not permanent.
Strong acid cationic resin: Although abundant, seawater is
not suitable for human consumption or for numerous
industrial uses due to its high concentration of dissolved
salts, including Ca and Mg ions, which cause it to have
hardness. Ion exchange with cationic resin has become an
effective method to remove these ions, softening seawater
and making it useful for a variety of applications. Seawater
contains Ca and Mg, salt-forming salts and increasing the
hardness of the water; for this, the cationic resin of strong
acid was used with its abbreviation SAC which is used in
the form of sodium (Na), which performs an ion exchange
allowing the hardness of the water produced by Ca and G
and when saturated with hardness allows its regeneration
with NaCl.
The reaction is as follows:
2R
1
-Na+Ca
2+
R
2
-Ca+2Na
+
2R
1
-Na+Mg
2+
R
2
-Mg+2Na
+
Producing a balance.
The hardness of the water decreased from 39.6 ml of EDTA
consumption as a very high hardness; subsequently after the
reaction with the resin the consumption was 2.1 ml of
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Pag. 19
EDTA, presenting high results in the removal of the
hardness of our sample:
Hardness without resin:
At 2.1 ml of 0.01 M EDTA consumption, where the
decrease in hardness of the sample water can be seen.
Hardness with resin:
Total hardness: 178 mg/L - Calcium hardness: 10 mg/L=
168 mg/L of Mg.
MgCO3=168 mg/L.
The hardness present in the sample is almost null.
For the analysis of chloride in the sample obtained, the
following calculation is analyzed:
100 ml M ------------- 2,432673 g Cl
-1
1000 ml M ------------ x=24,32673 g Cl
-1
Avogadro's law states that “equal volumes react in the same
way as long as their concentration is equal”.
Calculation for sodium chloride (NaCl):
Reactions with silver nitrate for the determination of the
purity of NaCl by titration of the sample obtained.
NaCl+AgNO
3
=AgCl+NaNO
3
Consumption: 24,3 ml de AgNO
3
3. Results.
Table 4. Final physical-chemical analysis of NaCl obtained
from the seawater sample.
Components
Results
Units
Alkalinity
60
mg/L
Chlorides
24326,73
mg/L
Conductivity
1558
us/cm
Hardness
50
mg/L
Salinity
0,14
%
Total Solids
779
ppm
pH
6,22
Temperature
27.5
ºC
The presence of CaCO3, CaSO4, NaCl, MgSO4, KCl,
MgCl2 and MgBr2; indicates that the water sample is
mineralized, i.e., it contains a significant amount of
dissolved salts. The initial purity of NaCl in the sample was
84.7314%, which means that there was a considerable
amount of impurities present. The sample was observed to
have a high hardness, possibly due to the presence of
calcium and magnesium ions. These ions can have negative
effects in various industrial and domestic processes. Ion
exchange with a strong cation resin was effective in
removing calcium and magnesium ions, which increased the
purity of the NaCl. Vacuum filtration and recrystallization
were performed to obtain purer crystals.
0.0824 g of the NaCl crystals were dissolved in 100 ml of
distilled water and the NaCl concentration was calculated,
obtaining a value of 97.23%. The final purity of NaCl,
97.23%, is significantly higher than the initial purity,
demonstrating the effectiveness of the purification process.
The different analyses and techniques used were carried out
with the purpose of obtaining the highest degree of purity of
NaCl; and to be able to use it in the laboratories allowing to
develop and improve the techniques used for the
purification of reagent grade NaCl decreasing the excessive
use of chemicals that can affect the composition of NaCl.
Sulfate results were 0.0 in the final NaCl sample. The
market is also driven by the extensive use of NaCl as a raw
material in the chemical industry to produce various
chemicals, including chlorine, sodium hydroxide and
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Pag. 20
sodium carbonates. These chemicals have a wide range of
applications, which is further driving the demand for salt.
3.1. Comparison of initial and final analyses.
Table 5. Initial Analysis
Components
Units
Alkalinity
96 mg/L
Chlorides
20020 mg/L
Conductivity
64000 us/cm
Hardness
4764 mg/L
Salinity
0,14%
Total Solids
1380 ppm
pH
6,27
Temperature
27,5 ºC
Table 6. Final Analysis.
Components
Units
Alkalinity
60 mg/L
Chlorides
24326,73 mg/L
Conductivity
1558 us/cm
Hardness
50 mg/L
Salinity
0,14%
Total Solids
779 ppm
pH
6,22
Temperature
27,5 ºC
4. Discussion.
The salt market has few formally constituted Ecuadorian
companies that share the local market for the supply of all
the industrial and human consumption salts required at the
national level, as we can see below:
Table 7. Distribution of the salt market.
Companies
Products
Annual
Production
Tons
Participat
ion
%
Average Dollar
Price
Ecuasal C.A.
Cris-Sal
150.000
76%
18.000.000.00
Famosal S.A.
Sea And
Salt
12.000
6%
1.440.000.00
Jueza S.A.
Pacific
Salt
15.000
8%
1.800.000.00
Proquipil
S.A.
Delisa
20.000
10%
2.400.000.00
Total, Sales
And Production
In Ecuador
197.000
100%
23.640.000.00
Source: Superintendencias De Compañías. Year 2013 Prepared by:
Tammy Rodríguez Balseca.
Fig. 6. Annual Production Tons.
Source: Superintendencia De Compañía. Year 2013 Prepared by: Tammy
Rodríguez Balseca.
Artisanal salt production has become a neglected trade
because traditional salt producers are unable to compete
with the large production industries established in the
market. Faced with such problems, the association of salt
producers of Manta, Ecuador has developed a proposal for
a refined salt production process that will contribute to the
achievement of this objective. A technical and operational
study is provided which is structured in the following
components: product characterization, flow chart of the salt
production process, geographic and micro location, and
study of salt production capacities. The aim is for the
association of salt producers to establish a business model
to enter the local and national market [22].
NaCl is an important raw material in the chemical industry,
since it has several uses. In the laboratory involved in the
study, NaCl is used as raw material to manufacture
parenteral solutions, such as: 0.9% NaCl injection and
injection of 5% dextrose with 0.9% NaCl (mixed solution).
These solutions are of great importance in the health field,
they are used in rehydration therapies in cases of acute
diarrhea and cholera, also for trauma, burns, when patients
have a deficit of body Na+ and control the distribution of
water in the organism.
According to the study conducted by Wang et al. (2020), a
novel method for purification of reagent grade NaCl is by a
combination of simple distillation and ion exchange
membranes. This technique combines the advantages of
these methods to effectively remove impurities such as
organic compounds, heavy metals and inorganic salts [23].
It can be stated that the standards for reagent grade NaCl
have a percentage of 99% to 100.5% purity both for
pharmacopoeia and those that require even higher
percentages such as ISO, however, there are standards that
indicate that reagent grade NaCl can have a minimum of
95% purity, these are usually specific especially in local
standards of certain countries which can accept this
minimum level of purity such as the Mexican Official
Standard (NOM) and the Ecuadorian Technical Standard
(NTE) INEN 1204.
76%
10%
6%
8%
ECUASAL
PROQUIPIL
S.A.
FAMOSAL S.A.
JUEZA S.A.
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Pag. 21
A comparison of NaCl purity standards established by the
USP, the Codex Alimentarius and INEN 1234 showed some
significant differences:
The USP indicates that its standards are the most
demanding, especially when it comes to the degree of
purity, since these grades are used in applications where
high purity and reliability are required, such as in the
manufacture of drugs, the minimum purity grade allowed by
the Pharmacopeia is 99.0% [24].
The Codex Alimentarius standards are focused on food
safety and establish a purity level that guarantees that the
NaCl used in food does not compromise the health of the
consumer; the accepted purity grade is 97.0% as a minimum
[25].
INEN 1234, which is a national standard, establishes
specific requirements for industrial grade NaCl, which is
used in a wide variety of applications. The required purity
level is lower compared to pharmaceutical and food
standards in this case it allows 95% purity as a minimum
[26].
5. Conclusions.
The initial characterization that was carried out allowed
obtaining the values of the different components present in
the sample to be analyzed and to start the present research,
with this it was demonstrated that it is possible to obtain
reactive grade NaCl using different techniques and analysis
where the use of reagents is not excessively applied, since
they change the composition of the different components
found in the sample.
It was possible to obtain reagent grade NaCl from seawater
from Crucita-Manabí, Ecuador, with a purity of 97.23%,
although it did not exceed USP international standards (99%
- 100.5%), it was demonstrated that it does exceed local
standards, which allows its application. The key finding of
this research shows that the seawater from Crucita-Manabí
has a chemical composition suitable for NaCl extraction.
The purification technique used, which combines
evaporation, recrystallization and ion exchange, was
effective in eliminating the impurities present in the
seawater and obtaining high purity NaCl, which determined
that the ion exchange stage with cation resin was crucial for
eliminating calcium and magnesium ions, The final
physical-chemical analysis of the NaCl obtained confirmed
that it meets purity standards, which makes it suitable for
use in laboratories and industries that demand a high degree
of purity.
The contributions of the present study demonstrate the
feasibility of obtaining reagent grade NaCl from Ecuadorian
seawater, which represents a significant contribution to the
local industry, since this study can now be replicated to
obtain high purity NaCl from other seawater sources, with
potential application in various industries. The results
obtained provide valuable information on the chemical
composition of Crucita-Manabí seawater and its potential
for NaCl extraction, which can contribute to the
development of new industrial initiatives in the region. The
relevance for local industry consists of the great impact of
being able to obtain reactive grade NaCl from Ecuadorian
seawater, since it reduces dependence on imports of this
product, which translates into foreign exchange savings for
the country. Promote the development of new industries and
even existing industries that require high purity NaCl, such
as the pharmaceutical, cosmetic and chemical industries,
generating new employment opportunities in the industrial
and scientific sector.
The regulations based on the present research are high
quality international regulations; however, there are local
regulations in different countries where a minimum
percentage of 95.0% of reagent grade NaCl is allowed,
which shows that the 97.23% of NaCl obtained in the
present work can be useful as a reagent use.
In short, this study opens new possibilities for the use of
seawater as raw material to obtain reactive grade NaCl,
contributing to the industrial and scientific development of
Ecuador.
6.- Author Contributions.
1. Conceptualization: Antonella Ferrin; Ramón Cevallos
2. Data Curation: Thalía Caicedo; Ariana García
3. Formal analysis: Segundo García; Ariana García
4. Acquisition of funds: N/A.
5. Research: Thalía Caicedo; Ramón Cevallos
6. Methodology: Segundo García; Thalía Caicedo
7. Project administration: Antonella Ferrin
8. Resources: N/A.
9. Software: N/A.
10. Supervision: Antonella Ferrin; Ramon Cevallos
11. Validation: Antonella Ferrin; Ariana García
12. Visualization: Thalía Caicedo; Ariana García
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Pag. 22
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