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Journal : Hexagon

PENGARUH SODIUM METABISULFIT TERHADAP KENAIKAN CONSENTRATE GRADE Cu DAN PENURUNAN KANDUNGAN PYRITE Ainun; Amirin Kusmiran; Rita Desiasni
Hexagon Jurnal Teknik dan Sains Vol 1 No 1 (2020): HEXAGON - Edisi 1
Publisher : Fakultas Teknologi Lingkungan dan Mineral - Universitas Teknologi Sumbawa

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (265.478 KB) | DOI: 10.36761/hexagon.v1i1.470

Abstract

PT. XX is one of the largest copper company in the world. Chalcopyrite (CuFeS2), bornite (Cu5FeS3) and pyrite (FeS2) are three major minerals in PT. XX is capable to produce about 2000 tons of concentrate per day, with design of processing capacity around 120,000 tonnes per day. To obtain grade Cu concentrates, an integrated method of extraction metallurgy (metal extraction) is usually carried out, so that this study focused on increasing low consentrate grade Cu, using lime and increasing pyrite content using the flotation method by varying pH and varying the dose of sodium metabisulfite. This is indicated by the percentage of Cu grade of 12.74%, the use of lime shows the percentage reduction of 50% and the decrease in pyrite to reach a percentage of 1.16%. Of the three variations of the SMB, namely no reagent, 150 and 300 in this study, 300 is a good dose in increasing grade Cu, reducing lime use and reducing pyrite content.
ANALISIS PENGARUH REAGEN MAX GOLD DAN GRINDING TIME TERHADAP RECOVERY Au Roby Maryudi; Amirin Kusmiran; Rita Desiasni
Hexagon Jurnal Teknik dan Sains Vol 1 No 1 (2020): HEXAGON - Edisi 1
Publisher : Fakultas Teknologi Lingkungan dan Mineral - Universitas Teknologi Sumbawa

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (186.262 KB) | DOI: 10.36761/hexagon.v1i1.471

Abstract

PT XX is one of the largest copper companies in the world. There are 2 main minerals spread in PT XX, namely copper (Cu) and Gold (Au). With a processing capacity of 120,000 tons per day, PT XX is able to produce around 2000 tons of concentrate per day. There are several problems in processing, including decreasing the acquisition of grade and recovery of copper and gold because the gold content is still covered in impurities. The sample used is derived from cleaner, namely Polishing mill produck. This study aims to see the effect of grinding time on Au recovery and grade concentrate and see the effect of Max Gold and Pax reagents on recovery of Au and Au grade. The method used is grinding and flotation. The grinding process varies 0, 5 and 10 minutes and flotation using reagents and max gold, based on the results of the study it was found that the smaller the particle size with 10 minutes grinding using the pax reagent the grade and recovery gain increased for grade 6.62 ppm and recovery 84.7%.
PENGARUH VOLUME SERBUK TERHADAP LAJU PENYERAPAN AIR PADA KOMPOSIT PARTIKEL TONGKOL JAGUNG (CORN COB) DENGAN MATRIKS EPOKSI Maulana Malik Ibrahim; Rita Desiasni; Fauzi Widyawati
Hexagon Jurnal Teknik dan Sains Vol 2 No 1 (2021): HEXAGON - Edisi 3
Publisher : Fakultas Teknologi Lingkungan dan Mineral - Universitas Teknologi Sumbawa

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (398.328 KB) | DOI: 10.36761/hexagon.v2i1.877

Abstract

Serbuk tongkol jagung adalah limbah alam yang digunakan sebagai penguat pada komposit papan partikel. Limbah tongkol jagung sangat berlimpah di Kabupaten Sumbawa Besar, NTB. Pada umumnya tongkol jagung mengandung bahan selulosa murni yang dapat menjadi bahan pengisi alternatif karena sifat seratnya yang kuat (modulus tinggi). Antara rantai-rantai selulosa terdapat ikatan hidrogen yang kuat, sehingga menghasilkan struktur kristalin. Untuk menentukan sifat fisik terhadap limbah tongkol jagung dalam pemanfaatannya. Oleh karena itu limbah tongkol jagung dijadikan sebagai media komposit papan partikel. Serbuk tongkol jagung menggunakan ukuran partikel 70 Mesh dengan variasi volume 30%, 40%, 50%, 60%, 70%. Pembuatan komposit dilakukan dengan metode hand lay up dengan campuran resin epoxy dan hardener menggunakan standar pengujian SNI 03-2105-2006. Hasil yang diperoleh dari uji daya serap air menunjukkan bahwa semakin meningkat variasi volume yang digunakan pada komposit maka semakin tinggi daya serap air pada papan partikel dan semakin lama waktu perendaman yang digunakan makan semakin tinggi persentase yang didapatkan. Sedangkan hasil dari persentase berat terendah yaitu pada variasi volume partikel 30% dengan lama waktu 24 jam sebesar 1.4% dan persentase tertinggi yaitu pada variasi volume partikel 70% dengan lama waktu perendaman yaitu 72 jam sebesar 14.2%. Dari hasil penelitian yang dilakukan menunjukkan bahwa komposit serbuk tongkol jagung dengan resin epoxy pada variasi volume 30% yang lebih baik dibandingkan dengan variasi volume 70%.
Indonesia PENGARUH UKURAN PARTIKELTERHADAP SIFAT FISIK DAN MEKANIK KOMPOSIT LIMBAH GERGAJI KAYU JATI DENGAN MATRIK RESIN EPOXY: PENGARUH UKURAN PARTIKELTERHADAP SIFAT FISIK DAN MEKANIK KOMPOSIT LIMBAH GERGAJI KAYU JATI DENGAN MATRIK RESIN EPOXY rita desiasni; Fauzi Widyawati; Riza Monica
Hexagon Jurnal Teknik dan Sains Vol 3 No 1 (2022): HEXAGON - Edisi 5
Publisher : Fakultas Teknologi Lingkungan dan Mineral - Universitas Teknologi Sumbawa

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (314.593 KB) | DOI: 10.36761/hexagon.v3i1.1467

Abstract

The physical and mechanical properties of particle composite materials are influenced by particle size. Variations in particle size will form different physical and mechanical properties. The size variations used are 100 mesh, 150 mesh, 200 mesh. The comparison between matrix and particles is 70% : 30% using the hand lay-up method. The test consists of physical tests, namely density and thickness expansion as well as mechanical tests consisting of Modulus Of Rapture (MOR) and Modulus Of Elasticity (MOE). The results of the physical density test were at a value of 0.93-1.02 g/cm3, the best density was at a particle size of 100 mesh with a value of 1.02 g/cm3. While the thickness test obtained values ??ranging from 9.3-9.8%, with the highest thickness development of 9.8% at a particle size of 100 mesh. While the results of the mechanical test itself, all variations in mesh size meet the standard, namely the highest MOR test is obtained in the 100 mesh variation, with a value of 341.15 kgf/cm2, while in the MOE test none of which meets the standards of SNI 03-2105-2006, the highest mesh variation is obtained by mesh. obtained at mesh 100 that is 8072.49 kgf/cm2.
PENGARUH FRAKSI VOLUME SERAT SISAL DAN FILLER SERBUK KAYU JATI TERHADAP KEKUATAN TEKAN DAN TARIK PAPAN KOMPOSIT Fitriah Assyurah, Dwi Nurul; Desiasni, Rita; Widyawati, Fauzi
Hexagon Vol 5 No 1 (2024): HEXAGON - Edisi 9
Publisher : Fakultas Teknologi Lingkungan dan Mineral - Universitas Teknologi Sumbawa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36761/hexagon.v5i1.3147

Abstract

Semakin meningkatnya permintaan akan bahan material ramah lingkungan untuk mengurangi dampak negatif terhadap kualitas udara global, kesehatan dan iklim global. Beberapa peneliti mulai fokus pada komposit berbasis biokomposit. Komposit dari serat alam dan partikel alam merupakan salah satu alternatif untuk komposit polimer karena keunggulannya dibandingkan dengan serat sintetis. Pada penelitian ini fraksi volume yang digunakan antara serat sisal dan serbuk kayu jati yaitu 5% serat : 15% partikel, 10% serat : 10% partikel, dan 15% serat : 5% partikel dengan volume resin tetap yaitu 80% menggunakan standar ASTM untuk uji bending dan uji tarik. Dari pengujian yang dilakukan, akan didapatkan beberapa data hasil pengujiam, nilai uji bending yaitu MOE teringgi pada variasi 15% serat : 5% partikel dengan nilai 6334,67 MPa dan nilai MOR sebesar 98,21 MPa diikuti dengan hasil terrendah pada variasi 5% serat : 15% partikel dengan nilai MOE sebesar 3987,13 MPa dan nilai MOR sebesar 68,19 MPa. Pada uji tarik didapatkan hasil tertinggi pada variasi 15% serat : 5% partikel dengan nilai nilai tegangan sebesar 71,36 MPa, regangan sebesar 1,61%, dan modulus elastisitas memperoleh nilai sebesar 44,31 GPa, pada variasi 10% serat : 10% partikel diperoleh hasil uji tarik terendah nilai tegangan 50,26 MPa, regangan sebesar 1,34%, dan modulus elastisitas sebesar 37,56 GPa. Hasil dari pengujian menunjukkan bahwa semakin meningkatnya fraksi volume serat membuat kekuakatan mekanik komposit semakin tinggi, penambahan serbuk kayu sebagai campuran filler komposit berfungsi untuk mengisi kekosongan pada pada selah-selah serat dan matriks saat proses pembuatan komposit.
PENGARUH VARIASI VOLUME LIMBAH SERBUK KAYU MAHONI DENGAN PERLAKUAN ALKALI TERHADAP KEKUATAN MEKANIK DAN MIKROSTRUKTUR KOMPOSIT PARTIKEL fatma, fatmawati hendrik; Desiasni, Rita; Widyawati, Fauzi
Hexagon Vol 5 No 1 (2024): HEXAGON - Edisi 9
Publisher : Fakultas Teknologi Lingkungan dan Mineral - Universitas Teknologi Sumbawa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36761/hexagon.v5i1.3636

Abstract

Kekuatan sifat mekanik dan fisik material komposit partikel dipengaruhi oleh fraksi volume serbuk dan matriks. Variasi fraksi yang digunakan 30:70%, 50:50%, dan 70:30% dengan metode hand lay up. Perlakuan awal dilakukan dengan perendaman NaOH 2% selama 1 jam. Hasil pengujian mekanik MOE treatment mendapatkan nilai uji tertinggi pada fraksi volume serbuk 30:70% yaitu 6145,51 kgf/cm² dan nilai uji MOR tertinggi pada fraksi volume 30:70% yaitu 167,38 kgf/cm². Sedangkan nilai MOE non-treatment tertinggi pada fraksi volume serbuk 30:70% yaitu 5540,9 kgf/cm² dan nilai uji MOR tertinggi pada fraksi volume 30:70% yaitu 156,6 kgf/cm². Hasil pengujian sifat fisik kerapatan tertinggi pada fraksi volume serbuk treatment 30:70% sebesar 0,87 gr/cm³ dan kerapatan tertinggi pada fraksi volume serbuk non-treatment 30:70% sebesar 0,78 gr/cm³. Hasil uji mekanik MOE tidak memenuhi standar JIS A 5908-2003 sedangkan uji mekanik MOR dan uji fisik telah memenuhi standar JIS A 5908-2003. Hasil pengujian mikrostruktur menunjukkan bahwa pada fraksi volume serbuk treatment 30:70% terlihat partikel lebih kasar yang menyatu sempurna dengan matriks. Sedangkan pada fraksi volume serbuk non- treatment 30:70% terlihat partikel lebih halus dan serbuk dengan matriks seakan tidak merekat dengan baik hal ini karena lapisan lilin yang ada pada serbuk
PENGARUH VARIASI VOLUME LIMBAH SERBUK KAYU MAHONI TERHADAP KEKUATAN FISIK, MEKANIK DAN MIKROSTRUKTUR KOMPOSIT PARTIKEL Desiasni, Rita; Widyawati, Fauzi; Nabila, Maitsa Fikri; Saiful, Muhammad
Hexagon Jurnal Teknik dan Sains Vol 5 No 2 (2024): HEXAGON - Edisi 10
Publisher : Fakultas Teknologi Lingkungan dan Mineral - Universitas Teknologi Sumbawa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36761/hexagon.v5i2.4143

Abstract

The strength of the mechanical and physical properties of particle composite materials is influenced by the volume fraction of the powder and matrix. The pretreatment was carried out by soaking 2% NaOH for 1 hour. The results of the MOE treatment mechanical highest test value at the powder volume fraction of 30:70%, which was 6145.51 kgf/cm² and the highest MOR test value at the 30:70% volume fraction, which was 167.38 kgf/cm². Meanwhile, the highest non-treatment MOE value at the 30:70% powder volume fraction was 5540.9 kgf/cm² and the highest MOR test value at the 30:70% volume fraction was 156.6 kgf/cm². The results of the physical properties test were the highest density at the 30:70% powder volume fraction of 0.87 gr/cm³ and the highest density at the 30:70% non-treatment powder volume fraction of 0.78 gr/cm³. The results of the MOE mechanical test do not meet the JIS A 5908-2003 standard while the MOR mechanical test and physical test have met the JIS A 5908- 2003 standard. The results of microstructure testing showed that at a fraction of powder volume of 30:70% it was seen that the particles were coarser which blended perfectly with the matrix.
REKOMENDASI REKLAMASI BERBASIS LINGKUNGAN DI LUBANG BUKAAN BEKAS PERTAMBANGAN RAKYAT DI PERKEBUNAN JAGUNG DEARAH KABUPATEN SUMBAWA Retongga, Nofrohu; Hayatuzzahra, Sayidatina; Safitra, Roby Mardiyan; Desiasni, Rita; Nuraga, Welly Handa
Hexagon Vol 6 No 1 (2025): HEXAGON - Edisi 11
Publisher : Fakultas Teknologi Lingkungan dan Mineral - Universitas Teknologi Sumbawa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36761/hexagon.v6i1.5311

Abstract

The aim of this study is to create a descriptive model of environment-based reclamation recommendations for ex-mining land in the Sumbawa region that is easy to understand and consider. This research consisted of three stages: literature studies from previous researchers were used as a basic reference to strengthen the background and discussion in the research, especially with regard to environment-based reclamation engineering, mapping of open hole points from former community mining, and environment-based reclamation recommendation models. well and precisely in the corn plantation while still considering the initial shape of the topography. Effective reclamation to restore agricultural land damaged and with holes caused by mining without permits by providing recommendations in the form of a descriptive model includes backfilling of openings, planting trees, or revegetation, considering it for agrotourism, and economical fish-farming ponds.
MODEL REKLAMASI LAHAN ADAPTIF UNTUK TAMBANG RAKYAT DI KABUPATEN SUMBAWA: STUDI KASUS DAN REKOMENDASI Nuraga, Welly; Hayatuzzahra, Sayidatina; Kallo, Nandhita Suri; Safitra, Robby Mardian; Desiasni, Rita
Hexagon Vol 6 No 2 (2025): Vol. 6 No. 2 (2025): HEXAGON - Edisi 12
Publisher : Fakultas Teknologi Lingkungan dan Mineral - Universitas Teknologi Sumbawa

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36761/hexagon.v6i2.6350

Abstract

income for the local community, also have negative impacts, namely land degradation with numerous abandoned and poorly managed former mining holes. This research aims to provide practical and sustainable recommendations for adaptive reclamation activities in former artisanal mining areas in Area Y, and to serve as a guide for realizing more responsible and sustainable artisanal mining practices. The research was conducted using a qualitative method through the analysis of relevant secondary data. The study results indicate that miners tend to leave former mining holes unreclaimed. This is due to miners' limitations in both technical knowledge and capital, rendering them incapable of carrying out reclamation independently. The impact of these abandoned mining holes has the potential to become a future hazard. The selection of an adaptive land reclamation model focusing on a flexible and participatory approach has proven to be an effective and efficient method for implementing reclamation activities in artisanal mining. Both government and non-governmental agencies can conduct intensive education and training to maximize local community participation for the success of reclamation activities