Thiosulfate leaching process for gold extraction

Increasing environmental concerns over the use of cyanide for gold recovery has intensified the need to deeply understand gold thiosulfate leaching system. Therefore, experimental and modelling work for the kinetics and equilibrium adsorption of thiosulfate, polythionates, gold and copper onto strong based anion exchange resin have been conducted in this study, and the results are concisely discussed in the thesis. Experimental procedures, reaction mechanisms and novel dynamic models for the adsorption phenomena were also proposed

Gold loading on ion exchange resins in non-ammoniacal resin-solution systems

The loading of gold using strong base anion exchange resin in non-ammoniac resin-solution (NARS) systems has been studied. The loading of gold onto ion exchange resins is affected by polythionate concentration, and trithionate can be used as the baseline in the system. The results also show that resin capacity on gold loading increases due to the increase in the equilibrium thiosulfate concentration in the NARS system. Gold loading performances show the need of optimization the equilibrium concentrations of thiosulfate in the NARS syste

Adsorption of Pb (II) Heavy Metals from Wastewater Using Modified Rice Husk as Adsorbent

Pb (II) heavy metal from wastewater as by-product of industrial activity often causes problem to environment. In order to minimize the amount of Pb (II), wastewater was treated in various ways, including adsorption process using adsorbent. Rice husks that containing lignin, cellulose, and hemicellulose are one of potential candidates to be utilized as adsorbent. The purpose of this research is to modify rice husk by using sodium hydroxide and citric acid and to know adsorption capacity and adsorption efficiency of modified rice husk adsorbent on Pb (II) metal uptake from wastewater. To identify substituted groups, analysis samples by using Fourier Transform Infrared was performed and to determine adsorbed amount of Pb (II) into adsorbent an Atomic Adsorption Spectroscopy Method was conducted. The result showed that optimum adsorption capacity and adsorption efficiency was 5.08 mg/g and 84.52%, respectively. These results were obtained on 60 ppm of Pb (II) adsorbate concentration and 0.8 M citric acid concentration for 150 minutes of contact tim

ANALISA PENGARUH RASIO SERAT DAN CANGKANG DENGAN UDARA BERLEBIH TERHADAP EMISI PROSES PEMBAKARAN PADA BOILER PABRIK KELAPA SAWIT

Pertumbuhan industri sawit yang tinggi dalam dua decade terakhir menempatkan Indonesia sebagai produsen minyak sawit terbesar dunia.  Industri sawit selain menghasilkan minyak nabati, juga menghasilkan limbah padat antara lain serat dan cangkang.  Sebagian dari limbah padat ini dimanfaatkan sebagai sumber bahan bakar di boiler untuk menghasilkan uap yang dimanfaatkan untuk pemrosesan dan menghasilkan energi listrik.   Paper ini melaporkan hasil kajian simulasi pengaruh rasio serat dan cangkang pada berbagai kondisi udara berlebih terhadap emisi gas hasil pembakaran yang dihasilkan. Penelitian ini menjadi penting mengingat pabrik minyak kelapa sawit ditengarai sebagai salah satu penghasil gas rumah kaca (GRK) dan pemerintah melalui Peraturan Menteri Negara Lingkungan Hidup Nomor 12 tahun 2010 bertekad mengurangi emisi GRK. Perangkat lunak ASPEN Plus (Versi 8.8) digunakan untuk memvariasikan rasio serat : cangkang berkisar 100:0; 30:70; 70:30; 50:50 dan 0:100 dengan udara berlebih 90, %, 120% dan 150% di atas kebutuhan stoikiometri. Bahan bakar dialirkan dengan laju tunak ke dalam proses sebesar 2700 kg/jam. Hasil simulasi menunjukkan bahwa kualitas emisi terbaik dihasilkan ketika rasio serat dan cangkang = 0 : 100 dengan udara berlebih sebesar 90%.  Pada kondisi seperti ini, gas  CO2 yang dihasilkan sebesar 719 kg/jam, NO 0,032 kg/jam dan laju abu sebesar 94 kg/jam. Heating value tertinggi juga diperoleh pada rasio serat dan cangkang = 0 : 100.  Hasil ini menunjukkan bahwa kehadiran serat di dalam bahan bakar memberikan kontribusi negatif terhadap emisi.  Kajian lebih mendalam masih diperlukan untuk meminimalisir limbah padat serat ini untuk digunakan sebagai sumber bahan bakar

Cu(II) Ions Adsorption Using Activated Carbon Prepared From Pithecellobium Jiringa (Jengkol) Shells with Ultrasonic Assistance: Isotherm, Kinetic and Thermodynamic Studies

Adsorption of Cu(II) ions from aqueous solution onto activated carbon (AC) prepared from Pithecellobium jiringa shell (PJS) waste was investigated by conducting batch mode adsorption experiments. The activation with ultrasound assistance removed almost all functional groups in the PJS-AC, while more cavities and pores on the PJS-AC were formed, which was confirmed by FTIR and SEM analyses. The Cu(II) ion adsorption isotherm fitted best to the Freundlich model with average R2 at 0.941. It was also correlated to the Langmuir isotherm with average R2 at 0.889. This indicates that physical sorption took place more than chemical sorption. The maximum Cu(II) ion adsorption capacity onto the PJS-AC for a dose of 1 g was 104.167 mg/g at 30 °C and pH 4.5, where the Langmuir constant was 0.523 L/mg, the Freundlich adsorption intensity was 0.523, and the Freundlich constant was 5.212 L/mg. Cu(II) adsorption followed the pseudo second-order kinetic (PSOKE) model with average R2 at 0.998, maximum adsorption capacity at 96.154 mg/g, PSOKE adsorption rate constant at 0.200 g/mg.min, temperature at 30 °C and pH at 4.5. The changes in enthalpy, entropy, free energy and activation energy were determined, and the results confirmed that Cu(II) adsorption onto the PJS-AC was exothermic chemical adsorption in part. There was a decrease in the degree of freedom and the adsorption was non-spontaneous

Adsorption of mercury(II) using activated carbon produced from Bambusa vulgaris var. striata in a fixed-bed column

Pollution by mercury dissolved in aqueous media causes a crucial problem for health and environment. In this study, activated carbon from Bambusa vulgaris var. striata was produced by chemical activation using NaOH for mercury adsorption. The effects of mercury initial concentrations namely 50 and 100 mg/L on the breakthrough characteristics of the adsorption process were defined. The mechanism of the adsorption process through the fixed-bed column was fitted to the Thomas model. The activated carbon was characterized by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The adsorption study with a continuous system and using the Thomas model showed that the highest adsorption capacity (q0) of mercury ions is 218.08 mg/g. It can be concluded that activated carbon from Bambusa vulgaris var. striata has a great potential to act as an adsorbent to remove mercury from water

Biosorbent Prepared from Calotropis Gigantean Stems for Adsorption of Cu(II) Ions from Aqueous Solution

Calotropis gigantea stems (CGS) has the potential to use as biosorbent for adsorption of Cu(II) ions. In this study, the CGS biosorbent (CGSB) was prepared by drying and grounding. The effect of independent variables on adsorption capacity were investigated. As the result, the maximum adsorption capacity of 53.457 mg/g was obtained the optimal condition which was initial Cu(II) ions concentration of 567.47 mg/L, CGSB size of less than 230 mesh, CGSB mass of 1 g, temperature of 27 oC, pH 5, and contact time of 60 min. The CGSB surface morphology was analysed using SEM. The adsorption of Cu(II) ions fitted well with pseudo first-order adsorption kinetic (PFO-AK) model (R2=0.99), and the PFO-AK adsorption capacity and rate constant obtained were 70.194 mg/g and 0.0877 g/mg.min, respectively. The adsorption isotherm of Cu(II) ions was in accordance with Freundlich model (R2=0.99), and the intensity and volume constants attained were 0.876 and 1.017 L/mg, respectively. This result showed that physical adsorption occurred dominantly than chemical adsorption. The application of CGSB on the wastewater of initial Cu(II) ions concentration of 389.31 mg/L from ex-mine pool of acid mine drainage (AMD) in Jantang village, Lhoong District, Aceh Besar, Aceh Province resulted in adsorption capacity of 37.52 mg/g with adsorption efficiency of 66.13%

The Connection of Authority between Central Government and Regional Government in Managing Mining and Forestry in Papua

Mining and forestry must be protected for the sake of benefit of the people. The protection of it can be seen in some regulation such as in Article 33 (3) of the 1945 Constitution of the Republic of Indonesia, the Law No. 11 Year 1967 concerning Basic Provisions of Mining has been replaced to the Law No. 4 Year 2009 concerning Mineral Mining and Coal, the Law No. 41 year 1999 concerning Forestry, the Law No 32 Year 2009 concerning Protection and Management Environment, the Law No. 23 Year 2014 concerning the Regional Government, and the Government Regulation No. 25 Year 2000 concerning Government and Province Authority as Autonomous Region. This research is categorized as empirical legal research or non-doctrinal legal research. It uses a juridical socio-cultural approach. It is conducted in the Province of Papua, primarily Jayapura, Kerom, Sarmi, Mimika, and Nabire Regency. Mineral mining and coals are non-renewable natural resources and they are national wealth that are controlled by the state for the greatest benefit of the people. Control upon mines by the state is conducted by the government and/or regional government. Government has the authority to determine the amount of production of every commodity per year in each province. The connection of authority between Central Government and Regional Government often overlaps jurisdiction in terms of their policies. To deal with such overlapping law icluding overlapping between the Law No. 21 Year 2001 concerning Special Autonomous of Papua and the Law No. 4 Year 2009 Governor of papua has issued the Governor Regulation No. 41 Year 2011 concerning Mineral, Metals, and Coal Mining Business to counterbalance the licensing act and mineral natural resources management even though eventually such regulation is not admitted by the central government. In the context of foresty, Licensing issues and authorities related with forest are regulated by the central government. The central government has not provided a room to regional government, and only a particular group of people with sufficient capital that could obtain license. After reform era, there are not any Regional Office in the province because currently it is handled in Forestry Department directly or Governor. Keywords: Connection of Authority, Central Government, Regional Governemnt, Mining and Forestr

Kecernaan Pelepah Sawit Fermentasi dalam Complete Feed Block (CFB) untuk Sapi Potong

Palm midrib that was one of all agroindustries unused. It could be pontential as animal feeding. It could used as animal feeding with made it Complete Feed Block (CFB). This research aimed to study the fermentation of  palm  midrib in complete feed block (CFB) on the quality of degestibility in vitro. The research was conducted three phases, the first phase of the fermentation of  palm  midrib grounding  with White Root Fungy, the second stage of the manufacture of complete feed block (CFB) and the third stage of the proximate analysis and digestibility analysis, The research was in  Nutrition  and animal feeding  Laboratory,  Agriculture Faculty, Srivijaya University. This research used Completely Randomized Design (CRD) with two treatments and five replications consisting of Formula 1 and Formula 2, the parameters were observed dry matter, crude fiber, crude protein, Extract Either, BETN, dry matter digestibility coefficients, organic matter digestibility coefficients and the concentration of N-NH 3. The result of CFB formulation  were formula 1 TDN: crude protein (47.32%: 13.93%), formula 2 (48.41%: 7.96%), where the results of proximate analysis showed F1: 98.66% DM, LK 13:19%, 7:03% PK, SK 35.79%, 40.24% BETN, and F2: 98.41% DM, LK 16:43%, PK 6.25%  SK 24.06%, 49.50% BETN. Formulations showed that all treatments influence  non significantly (p> 0.05),  organic matter digestibility (85.00% vs. 85.70%), dry matter digestibility (59.42% vs. 59.62% vs. 16.72%) and the concentration of N-NH 3 (2.2% versus 1.8 %). The conclusion of this study is the complete feed block (CFB) can be used as a ruminant animal feeding, but should pay attention to aspects of quality and palatability

Perbedaan Teknik Kastrasi Terhadap Bobot Badan, Panjang dan Volume Skrotum pada Sapi Bali

Penelitian ini bertujuan mengamati perbandingan teknik kastrasi pada caudal dan vas deferent terhadap bobot badan, panjang dan volume skrotum pada sapi Bali. Penelitian ini dilaksanakan pada bulan Juni sampai Agustus 2016 dilaksanakan dikandang percobaan Jurusan Peternakan, Fakultas Pertanian, Universitas Sriwijaya. Metode penelitian menggunakan 6 ekor sapi Bali dibagi menjadi  dua  teknik,  Pertama  3  ekor  sapi   yang  dikastrasi  dengan  teknik pemotongan pada  caudal (P0) dan kedua 3  ekor sapi  yang dikastrasi dengan teknik pemotongan pada vas deferent (P1) metode statistik yang digunakan adalah uji  T-Test.  Hasil  penelitian  menunjukan  adanya  perbedaan  bobot  badan  pada kedua metode teknik kastrasi pada caudal maupun pada vas deferent, sedangkan pada panjang dan volume skrotum tidak memberikan perbedaan yang secara signifikan terhadap perlakuan kedua metode kastrasi baik pada caudal maupun vas deferent.