CHARACTERIZATION OF MAGNETIC MINERALS OF IRON SAND PASIA NAN TIGO PADANG BEACH USING X-RAY DIFFRACTION (XRD)

The mineral extraction of iron sand from Pasia Nan Tigo Beach has been carried out. Iron sands in this area are widely spread and have decent potential but have not been used optimally. The iron sand of Pasia Nan Tigo Beach contains minerals that are indicated by the variation in susceptibility values of type 265.8×10 -8 m 3 /kg to 12,445.53×10 -8 m 3 /kg. Therefore, it is necessary to separate minerals from iron sand so that the minerals contained in them are known so that they are suitable for usability. The iron sand obtained is extracted using two magnets, namely a strong magnet and a weak magnet. The extraction results from iron sand still contain impurities to remove them, the sand is purified and then the sand extraction results are characterized using the XRD method. Content The type and structure of the mineral species found in the samples extracted from iron sand using strong magnets are Magnetite (Fe 3 O 4 ) with Cubic structure, Hematite (α-Fe 2 O 3 ) with Hexagonal structure, and Ilmenite (FeTiO 3 ) with Hexagonal structure. While the use of weak magnets is Magnetite (Fe 3 O 4 ) with Cubic structure, Hematite (α-Fe 2 O 3 ) with Rhombohedral structure, and Ilmenite (FeTiO 3 ) with Rhombohedral structure. Meanwhile, the non-magnetic mineral namely Quartz (SiO 2 ), works as an impurity. The average crystal size using a strong magnet for PNT-B01 0-5 cm is 100.85 nm and a weak magnet is 49.36 nm, sample A06 30-35 cm uses a strong magnet of 88.25 nm and a weak magnet of 46, 80 nm, meanwhile sample B10 0-5 cm with a strong magnet of 109.22 nm and a weak magnet of 45.60 nm. The results of XRD measurements showed the types of magnetic minerals found in the extraction findings on the PNT-B10 sample at a depth of 0-5 cm. The diffraction angle of 2θ is found at peaks of 36,600°, 59.920°, and 68.261° with distances between d [Å] of fields 2.455Å, 1.544 Å, and 1.374 Å, namely minerals Magnetite with relatively low intensity obtained from the measurement results are 10.9%, 7.58%, and 6.8% with the grid parameters are a=b=c=8.118 Å; α=β =c=90°. Meanwhile, the minerals that are known at the diffraction angle at the peaks of 23.642°, 34.991°, and 52.318° are minerals Ilmenit e with relative measurement intensities of 7.83%, 18.2%, and 6.24% with lattice parameters a=b=5,128 Å and c=14,187 Å; α=β=90° and γ=120° with space group R-3 with structure Hexagonal. Other types of minerals that are present at the diffraction angle (2θ) at the peak of 27.794° namely Pyroxene and the diffraction angle (2θ) of 20.850°, 26.683°, 39.517°, and 50,132° the known minerals are Quartz which shows non-magnetic minerals and with the most significant intensity reaching 100%. Thus the diffractogram analysis shows that the magnetic minerals that make it up iron sand are Magnetite (Fe 3 O 4 ) and Ilmenite (FeTiO 3 ).


INTRODUCTION
Natural resources abound in Indonesia. Indonesia has a tectonic layout that supports its potential natural resources, such as large mineral mines, due to geological conditions [1] . Iron Sand is one of Indonesia's mineral mines, and it may be found across the country, including along the southern coast of Java, West Nusa Tenggara, and Sumatra [2] . West Sumatra is one of the provinces with the highest potential for iron sand, but it has yet to be completely utilized [3] Pasia Nan Tigo Beach is one of those. Pasia Nan Tigo Beach is a sloping and sandy beach in Padang City's Koto Tangah sub-district. It is composed of grayish-brown sand with coarse granules [4] . This area has a bunch of iron sand, which has a lot of potential and economic value. The material (rock, sand, gravel) is carried away from the river and sedimented due to the passage of seawater, and the material is distributed to the coast continuously for a long time, resulting in the addition of iron sand deposits.
The mineral content of iron sand is generally present in metal oxides [5] . Sand contains a lot of iron, titanium, silica, and other elements [6,7] . The minerals have 88% magnetic and 12% non-magnetic [8] . Minerals having high magnetic characteristics are known as magnetic minerals [9] , Iron magnetite (Fe3O4), hematite (α-Fe2O3), and maghemite (β-Fe2O3) are the most abundant minerals in the sand, and they have industrial applications as a mixed dye (filler) for paints and as a base material for permanent magnets. Magnetite is a mineral that is used as a base for dry ink or toner [10] , laser printers, magnetite nanoparticles as biomedical applications [11] and anti-cancer [12,13] , the manufacture of ferrous metal [5] . Minerals Hematite can also be used as a major component in the manufacture of photoelectrochemical solar cells [14] , manufacture of magnets [15] , raw materials for lithium batteries [16] , and industrial materials based on magnetism [17] . The magnetic mineral content of iron sand is very large, especially on Pasia Nan Tigo Beach, so it cannot be utilized optimally [2] .
Material can be determined by its magnetic properties by measuring its magnetic susceptibility value [18][19][20][21][22] . One thing that affects the susceptibility value is Fe which has ferromagnetic properties. Beach sand Pasia Nan Tigo iron-containing magnetic minerals as indicated by the variation in magnetic susceptibility 1,303.57×10 -8 m 3 / kg, 2,882.43×10 -8 m 3 / kg, and 12,445.53×10 -8 m 3 / kg. Therefore, it is necessary to separate the minerals from iron sand to make it more efficient. The extraction process is carried out using manual extraction or using permanent magnets with several draws [23,24] with the percentage of magnetic mineral content drawn using a strong magnet, namely 58.7%, 80.9%, and 31.70% while using a weak magnet of 15.5%, 2.62%, and 4.09% and further characterized using X-Ray Diffraction (XRD).

METHODS
This research includes sampling, sample preparation, extraction of iron sand samples, measurements using XRD, data analysis, and interpretation. Sampling was carried out at a location between 00°17,974'-00°64,961' South latitude and 100°19,791'-100°31,850' East Longitude which is located in Pantai Pasia Nan Tigo, Koto Tangah District, Padang City which stretches 7.2 km and divided into three regions (Pasia Jambak, Pasia Kandang, and Pasia Sabalah). Around this area, there are estuaries where the river and sea meet, namely Muaro Anai, Muaro Baru, and Muaro Panjalinan ( Figure 1). The coastal area of Pasia Nan Tigo is located at an altitude of 0-3 meters above sea level, the width of the beach ranges from 2 to 21 meters and the slope of 0-2% causes this village to be classified as lowland [25] . Therefore, Pasia Nan Tigo Beach is a sloping and sandy beach. The sand in this area consists of sand that is grayish brown with coarse grains [4] . Furthermore, iron sand extraction is used to separate magnetic and non-magnetic materials during the separation process. The following is the magnetic mineral extraction process for iron sand: 1) Strong magnets and weak magnets are being used to extract iron sand samples that have already been dried and weighed up to 100 grams ( Figure 2). The process to extract material from a mixture is called extraction [26] . The separation of magnetic minerals from the sources is also known as iron sand magnetic mineral extraction. Extraction using a strong magnet aims to separate sand containing Fe and other than Fe while using a weak magnet aims to make the iron sand attracted by the magnet have strong magnetic or magnetic properties. 2) Furthermore, iron sand extraction is done both with strong and weak magnets by extracting a sample with a strong magnet that has a pull of up to 20 times the pull of a weak magnet. Semua mineral magnet, baik yang magnetnya lemah maupun yang magnetnya kuat, mengandung efek tarikan dengan magnet yang kuat. magnet yang lemah menarik pasir besi yang telah ditarik kembali oleh magnet yang kuat. As a result, iron sand is obtained, which has a stronger magnet and looks blacker in color, whereas the remainder of the withdrawal using a strong magnet looks brownish and the sand's magnetism is no longer visible ( Figure 3). 3) Other impurities are still contained in the magnetic minerals that are attracted by the magnet. As a result, the samples were cleaned with Aquadest in an Ultrasonic Cleaner BK-1200. Ultrasonic Cleaner uses ultrasonic waves to create vibrations that easily remove impurities from magnetic minerals. 4) The sample is then dried once it has been washed. 5) After drying, the sample is placed in a holder and brought to the Material Physics Laboratory, Department of Physics, FMIPA, Padang State University, where it is analyzed using a PANalytical X Pert Pro PW 3060/10 XRD with a Pixel 1-D type detector to determine the mineral type. (Figure 4).
By comparing measured data to mineral databases, XRD is used to determine mineral types. While for the crystalline phase in a material it was carried out with lattice parameters and the diffraction pattern found at a certain peak angle was characteristic of a sample. The crystal size can be determined using the equation Debye Scherrer [27] .
(1)  Table 1 shows that iron sand in Pasia Nan Tigo Village has different magnetic mineral content percentages. After separation using strong magnets, iron sand from the PNT20-0616-1-A06 sample at a depth of 30-35 cm was more attracted than the PNT20-0616-1-B01 cm and PNT20-0616-1-B10 samples at a depth of 0-5 cm. Meanwhile, using a weak magnet has a percentage of the magnetic mineral content of 15.55%, 2.62%, and 4.09%. Of the three coastal sampling locations, Pasia Jambak has a high percentage of magnetic mineral content for weak magnetic drawing compared to other sample locations.

Data measurement Results sample results from iron sand extraction with XRD
measurement results for sample extraction of iron ore by XRD as a function of diffraction intensity diffraction angle (2θ). The measurement data is obtained in the form of a graphic called a diffractogram. Analysis of the diffractogram was carried out to obtain the type of mineral, crystal structure, and crystal size. The mineral type is shown by comparing the angle of diffraction (2θ), relative intensity(Ir) of the measurement results with the database mineral.

1) Measurement data of iron sand extraction samples using strong and weak magnets
The samples from the iron sand extraction of PNT area sample B01 were measured using XRD at a depth of 0-5 cm. Mineral kinds are recognized using the diffraction angle (2θ), and the distance of fields (d), with magnetic and non-magnetic minerals being recognized by comparing measurement techniques such as data mineral database.  At an angle of 2θ with a peak of 30.400°, and 36.158°, XRD tests in the PNT20-0616-1-B01 sample at a depth of 0-5 cm using a strong magnet (Table 2) indicate the type of magnetic minerals present, namely Magnetite [28,29] , Hematite is obtained at a diffraction angle of 2θ with a peak of 49.640° and Ilmenite is obtained at a diffraction angle of 23.955°, and 40.350°. Other mineral types are Magnesioferrite, which has a diffraction angle of 35.143°, and Quartz a non-magnetic mineral which has diffraction angles of 2θ 26.662°, 60.102°, and 81.582° with the most significant intensity reaching 100%. The diffractogram analysis reveals that magnetite (Fe3O4), hematite (α-Fe2O3), and ilmenite (FeTiO3) are the minerals that make it up to iron sand. Because many non-magnetic minerals, such as Quartz and Pyroxene, are still identified from XRD measurements, iron sand extraction was performed using a weak magnet to obtain magnetic minerals.

1) Measurement data of iron sand extraction samples using strong and weak magnets
The samples from the iron sand extraction of PNT area sample B01 were measured using XRD at a depth of 0-5 cm, yielding a diffractogram ( Figure 6) with some peaks visible. Mineral kinds are recognized using the diffraction angle (2θ), and the distance of fields (d), with magnetic and non-magnetic minerals being recognized by comparing measurement techniques such as data mineral database (Tables 4 and 5).  The magnetic mineral types found in the extraction results were shown by the XRD measurements on the PNT-A06 sample at a depth of 30-35 cm using a strong magnet ( There are still many non-magnetic minerals, such as quartz, based on the results of XRD measurements using weak magnets, so weak magnets are used to obtain magnetic minerals. The results of the measurements were matched to mineral databases (  [30,31] .

1) Measurement data of iron sand extraction samples using strong and weak magnets The
The samples from the iron sand extraction of PNT area sample B01 were measured using XRD at a depth of 0-5 cm, yielding a diffractogram ( Figure 7) with some peaks visible. Mineral kinds are recognized using the diffraction angle (2θ), and the distance of fields (d), with magnetic and nonmagnetic minerals being recognized by comparing measurement techniques such as data mineral database.  Based on the results of XRD measurements using strong magnets, there are still many nonmagnetic minerals such as quartz, so weak magnets are used to obtain magnetic minerals. The results of the measurements were matched to mineral databases (Table 7), the magnetic minerals that were found in the result of the extraction are known in the intensity of the diffraction angle (2θ) is at the peak 35,785 °is a mineral Hematite that has a lattice parameter a=b= 5,031 Å and c= 13.737 Å; α=β=90° and γ=120° with space group R-3c with structure Rhombohedral, at diffraction angle intensity (2θ) 30.077°, 43.106°, 53.422°, and 62.505° are Magnetite with lattice parameters of a=b=c= 8.385 Å; α=β=γ= 90° with a structure Cubic, while the diffraction angle (2θ) is 32,620 °, and 73,700 ° namely Ilmenite and the lattice parameters a=b=5.0900Å and c=14.0900 Å; α=β=90° and γ=120° with space group R-3 with Rhombohedral structure. Strong magnets had an average crystal size of 109.22 nm, while weak magnets had an average crystal size of 45.60 nm. Therefore Extraction using a weak magnet obtained magnetic minerals that are more dominant, namely Magnetite (Fe3O4), Hematite (Fe2O3), and Ilmenite (FeTiO3) [32,33] .

CONCLUSION
Based on the results of measurements compared to databases a mineral was generated using XRD. The types of minerals, crystal structure, and crystal size of Pasia Nan Tigo Beach's iron sand can be seen. The content Magnetite (Fe3O4) with a Cubic structure, Hematite (α-Fe2O3) with a Hexagonal structure, and Ilmenite (FeTiO3) with a Hexagonal structure are kinds and structures of magnetic minerals found in samples retrieved from iron sand using powerful magnets. Magnetite (Fe3O4) with a Cubic structure, Hematite (α-Fe2O3) with a Rhombohedral structure, and Ilmenite (FeTiO3) with a Rhombohedral structure all use a weak magnet. Meanwhile, the non-magnetic mineral identified, Quartz (SiO2) performs the role of even an impurity. PNT-B01 0-5 cm has an average crystal size of 100.85 nm and a weak magnet of 49.36 nm, sample PNT-A06 30-35 cm has an average crystal size of 88.25 nm and a weak magnet of 46.80 nm, and sample PNT-B10 0-5 cm has an average crystal size of 109.22 nm and a weak magnet of 45.60 nm.

ACKNOWLEDGMENTS
The UNP Research and Service Institute funded the Applied Research plan with contract number 1617/ UN35.13/LT/2020, which the author gratefully acknowledges.