Andi Rustandi

The Use of Mixture of Piper Betle and Green Tea as a Green Corrosion Inhibitor for API X-52 Steel in Aerated 3.5 % NaCl Solution at Various Rotation Rates

Flow induced corrosion due to the presence of turbulent flow often occurs which causes severe internal thinning and promotes premature leakage. In practice, the common method for controlling such internal high corrosion rate is chemical injection using corrosion inhibitor such as amine based which utilizing adsorption or film forming mechanism. Unfortunately, the protection performance of such inhibitor might be less effective due to turbulent flow induced. The aim of this work is to study the use of mixture of piper betle and green tea as an alternative of green corrosion inhibitor (eco-friendly) to reduce the corrosion rate of API X-52 steel in aerated 3.5 % NaCl solution in turbulent flow condition whether high inhibitor efficiency can be achieved. The method of corrosion rate measurements was conducted using electrochemical polarization equipped with CMS100-Gamry Instruments and DC105 software as well as Rotating Cylinder Electrode (RCE) simulation. The mechanism of inhibition was also investigated using Electrochemical Impedance Spectroscopy (EIS) method with EIS300 software. The results showed that the addition of mixture of 1000 ppm piper betle and 4000 ppm green tea extracts with Reynold number ranging from 0 up to 30000 reduced the corrosion rates significantly with its approximately 90 % inhibitor efficiencies achieved. In addition, EIS spectra showed that in the absence of corrosion inhibitor, the Warburg impedance (diffusion controlled) was significantly attributed to the overall impedance but in the presence of corrosion inhibitor, capacitive impedance (charge transfer controlled) was mainly attributed to the overall impedance.

Effect of Reduction Process Parameter in Direct Reduction Process of Laterite to Produce Substitute Pig Iron for Thin Wall Ductile Iron Material

Many parameters are involved in reduction process but carbon availability, process temperature and process time hold the role. This research conducted to find the relation effects of three main factors mention previously. This research used lateritic rocks from Sebuku Island as the iron source and coal as carbon source. Particle size with the highest Fe content is used for reduction process. Variations in reduction process made in mass ratio, process temperature, and process time. The mass ratios are 1:4 and 1:5. The process temperatures are 900OC and 1000OC. Process times are 10, 20, and 30 minutes. Characterization process used XRD and XRF. The results show that carbon availability is important and combinations of higher carbon supplies and process temperature are able to prevent further oxidation.

Corrosion Inhibition of Low Carbon Steel by Pluchea Indica Less. in 3.5% NaCL Solution

Inhibition of low carbon steel (LCS) corrosion in 3.5% NaCl of Pluchea indica Less. leaves extract (PILLE) has been studied using various investigation techniques such as weight loss and polarization methods. The percentage of inhibition increased as the concentration of the inhibitor increased. The results of corrosion test reveal that the extract behaves as a mixed type corrosion inhibitor. Optimum inhibition is reached from 3 mL gambir extract for immersion time of 216 hours. Fourier transform infrared (FTIR) spectroscopy result of adsorbed film on LCS surface containing PILLE shows that in changes in the functional group frequencies of the organic component of the extract.

The Effect of Ferrite Content on Mechanical Properties and Corrosion Behaviour of Austenitic Stainless Steel 308L Weld Metal

Ferrite is well known as a beneficial phase that can prevent hot cracking phenomena and act as strengthening phase in austenitic stainless steel weld metal. This paper investigated mechanical and corrosion behaviour of austenitic weld metal grade 308L which deposited by SMA (Shielded Metal Arc) method with various ferrite content. Several tests such as tensile at room temperature, charpy impact V-notch and lateral expansion at cryogenic temperature-196°C were conducted to observe mechanical behaviour. Electrochemical testings such as Cyclic Polarization method and Electrochemical Impedance Spectroscopy (EIS) were also performed. Controlling weld metal 308L with ferrite number (FN) 2 and manganese content about 1.53 % could achieve excellent toughness and hot cracking resistance as well as improved pitting corrosion resistance for cryogenic purpose.

The Effect of Sodium Chloride Concentration on Corrosion Resistance of Austenitic Stainless Steel 316L and SMA Weldment

Austenitic stainless steel 316L has been widely used in marine environment which containing sodium chloride solution (NaCl). In order to provide matching properties with parent metal, filler metal SMA 316L is commonly produced with slightly over alloyed composition. This work investigated the corrosion behavior of base metal 316L and SMA 316L weld metal by using Electrochemical Impedance Spectroscopy (EIS) to evaluate the mechanism of corrosion behavior based on impedance magnitude measurement at room temperature (27°C ). Various concentrations of sodium chloride solution i.e 1%,2%,3.5%,4% ,and 5% NaCl were prepared. Optical Metallography was also conducted to compare microstructure of base and weld metal. By using Nyquist graphs and its related equivalent circuit parameters showed that impedance magnitude of weld metal was higher which compared to base metal at any NaCl concentration. Metallography examination revealed that weld metal 316L had dendritic austenitic with delta ferrite and 316L base metal had austenite with typical twin boundaries structure. Higher chromium and nickel content in weld metal 316L was the key variable that control passive film characteristic rather than its microstructure. The lowest impedance magnitude of both 316L and all-weld metal 316L at various concentration was at 3.5% NaCl. Dissolved oxygen at 3.5% NaCl reach maximum solubility which causes severe pitting corrosion.

Influence of roasting-quenching pretreatment on the rice husk silica prepared by calcination method

Calcination is a simple method to produce silica from rice husk (RH). One of the key to obtain higher purity silica from rice husk by calcination method is the effectiveness of impurities removal, especially potassium, from RH surface before calcination process. So, in the present study, an attempt has been made to produce high purity silica powder by using calcination method with the combination of roasting-quenching and acid leaching as a pretreatment to eliminate metal impurities, especially potassium, detected by using inductively coupled plasma mass spectrometry (ICP-MS). Finally, the high purity silica, 99.928% was obtained by roasting and calcination temperature of 300°C and 650°C, respectively. However, by considering less energy usage and silica purity achievement, the combination of 300°C roasting-quenching, 1M hydrochloric acid leaching, and calcination at the temperature of 600°C was the best route.

The Effect of Reduction Parameter in Processing Lump Ore with Green Sugarcane Bagasse Reductor in Muffle Furnace

Sugarcane bagasse has demonstrated its ability to act as a reductor in iron-reduction process. As a reductor, bagasse has specialties as double-acting reductor equiped with volatile matter. This is the first study of the use of bagasse as reductor in iron-reduction process. The parameter concluded from this study was used for the second study which report has been submitted for publication. The aim of this study is to discuss the effect of reduction process parameter to the use of bagasse as reductor. This study was divided into 2 step. The first step is determining the optimum reduction process temperature and weight ratio. The reduction temperature varied as 700, 800, 900 and 1000 °C and the weight ratio are 1:2 and 1:4. The process duration is 30 minutes. The second stape is determining the process duration. The process duration will be varied as 30, 45 and 60 minutes. The condition of bagasse is air dried basis. The result shows that the reduction process produced wustite (FeO).

Other Oxides Pre-removed from Bangka Tin Slag to Produce a High Grade Tantalum and Niobium Oxides Concentrate

Indonesia, as the second largest tin producer in the world, has a byproduct from the production of tin. This byproduct is in the forms of tin slag containing tantalum pentoxide (Ta2O5) and niobium pentoxide (Nb2O5). This study focuses on the recovery of tantalum pentoxide and niobium pentoxide from the tin slag. In the process, one part of the tin slag sample was sieved only (BTS), and the other was roasted at 900°C, water quenched and then sieved (BTS-RQS). Samples BTS and BTS-RQS were characterized by thermo gravimetric analysis (TGA) and X-ray flourence (XRF). One part of BTS-RQS sample was dissolved in hydrofluoric acid (HF) and the other was dissolved in hydrochloric acid (HCl), washed with distilled water, then dissolved into sodium hydroxide (NaOH). Each sample was characterized by using XRF. The BTS sample produced the highest recovery of 0.3807 and 0.6978% for Ta2O5 and Nb2O5, respectively, from the particle size of -1.00+0.71 and a fraction of 47.29%, while BTS-RQS produced the highest recovery of 0.3931 and 0.8994% for Ta2O5 and Nb2O5, respectively, on the particle size of -0.71+0350 and a fraction of 21%. BTS-RQS, dissolved with 8% hydro fluoride acid, yields tantalum pentoxide and niobium pentoxide with a ratio of 2.01 and 2.09, respectively. For the sample BTS-RQS dissolve first with 6M hydrochloric acid, washed with distilled water, then dissolved with sodium hydroxide 10M, the yield ratios are 1.60 and 1.84 for tantalum pentoxide and niobium pentoxide, respectively. In this study, it is found that the dissolution by using hydrofluoric acid 8% yields the best ratio.

Study of Active Compounds from Red Cabbage (Brassica oleracea var. capitata f. Rubra) Extract as a Green Corrosion Inhibitor for API 5L Grade X60 Steel in NaCl 3.5% Environment

Red cabbage extract has been investigated in this work whether it would perform as a green corrosion inhibitor for API 5L grade X60 steel in 3.5% NaCl environment. Based on the FTIR and LC-MS analysis the active compounds of corrosion inibitor were hydroxyl, carbonyl and cyanidin. The Tafel polarization test results showed that red cabbage extract performed as a mixed corrosion inhibitor and the Electrochemical Impedance Spectroscopy test results showed that the impedance, polarization resistance and capacitive resistance of steel surface increased with the addition of red cabbage corrosion inhibitor. Based on evaluation of the testing results red extract red cabbage performed significant corrosion inhibition effect. The inhibitor efficiency increases with increased corrosion inhibitor concentration and the optimum inhibitor percent efficiency achieved 81%. The adsorption mechanism of red cabbage corrosion inhibitor can be considered as a Langmuir Isotherm

The Effects of Reduction Parameter to Composite Pelet of Iron Ore and Coal Using Single Conveyor Belt Hearth Furnace

Iron ores should be separated from oxygen and impurities which are coming along during the mining process. The separation process is known as reduction. There are two types of reduction process, and the most common is direct reduction process (DRP). There are several parameters in DRP which will determine the quantities of the product known as direct reduction iron (DRI). This worked discussed the effect of reduction temperature and pellet heap to the quantities of DRI using single conveyer belt Hearth furnace. The worked was done in laboratory scale using composite pellets with 14 mm in diameter. The ratio of iron ore to coal in the composite pellet is 1 to 1. The reduction process temperatures are 500oC, 700oC and 900oC. The reduction time is 25 minutes. While the pellets heap are also varied to 1, 3, 5, 7, 8 and 9 layers. The results show that DRI was formed in 700OC and the quantities of DRI are in line with the reduction temperatures and layers of composite pellets heap.