Hashim Hussin

A novel rapid mist spray technique for synthesis of single phase precipitated calcium carbonate using solid-liquid-gas process

Various techniques and approaches have been designed to synthesize precipitated calcium carbonate. We used a continuous sprayed-mist technique that induced spontaneous precipitation reaction of the droplets with the higher surface area when in contact with the gas. The effects of optimum reactant concentration, gas flow rate, and reactant feeding rate including reaction conditions were investigated. The effectiveness of the techniques was scrutinized by analyzing the resultant PCC characteristics, especially the particle phase morphology and size distribution using XRD, FTIR, and SEM. The variation of initial concentration of milk of lime with different gas flow rate was studied. Experimental results, as well as XRD and FTIR, indicated that all the products produced were favorable for the formation of calcite. SEM revealed that the morphologies of PCC were all rhombohedral and tended to adhere to each other (twinning). It was found that production of PCC by using spray-mist method is suitable for lower initial concentration of Ca(OH)2 and higher gas flow rate only.

The Preparation of Iron-Free TiCl4 from Reduced and Nitrided Ilmenite by Polyethylene Terephthalate

In this study, titanium tetrachloride (TiCl4) solution was successfully synthesized from titanium oxycarbonitride (TiOxCyNz) by means of chlorination process at low temperatures. Iron-free TiOxCyNz was prepared by carbothermal reduction and nitridation of Ilmenite (FeTiO3) with coal-75 wt. % PETas a reductant in a H2/N2 gas mixture. Aeration leaching via the Becher process for iron removal with NH4Cl solution was the preferred method for iron removal. The effect of reduction temperature on the synthesis of titanium oxycarbonitride (TiO0.02C0.13N0.85) powder suitable for iron removal has been investigated in the temperature range of 1150–1250°C. The reduced-nitrided ilmenite samples were characterized by XRD and SEM/EDX in terms of phases and morphology. The results showed that iron was formed in spherical and separated particles from TiOCN. Furthermore, the effects of temperature between 350–450°C and soaking time from 1 to 3 hours on the chlorination of iron-free titanium oxycarbonitride have been evaluated. The evaluation was based on design of experiment (DOE) to identify the significant variables on the extent of titanium extraction. DOE analysis based on weight loss validated by ICP tests, indicated a good extraction of titanium and synthesis of TiCl4 at 450°C.

The Effects of Experimental Variables on Iron Removal from Nitrided Malaysian Ilmenite by Becher Process

Iron-free titanium oxycarbonitride (TiOxCyNz) is a promising feedstock for production of titanium tetrachloride (TiCl4) at low temperatures. In this study, the effects of leaching variables such as temperature, time, particle size of staring material and concentration of the leaching solutions were evaluated on iron removal from nitrided Malaysian ilmenite by Becher process. The nitrided ilmenite was prepared by isothermal reduction with graphite at 1200 °C for 3 h in H2-N2 atmosphere. The aerated leaching experiments were conducted at 50–90 °C with addition of 0.3–2.0 wt% of NH4Cl catalyst. The highest extent of iron removal (XFe) was obtained at about 96.2% for the sample leached at 90 °C for 7 h with 2.0 wt% NH4Cl. The iron concentrate and titanium oxycarbonitride product were characterized by ICP-OES, XRD, XRF and SEM-EDX analyses. The results indicated that the aeration leaching process was a successful route to prepare low-iron titanium oxycarbonitride.

Effect of Grinding Aids in Cement Grinding

In fine grinding of cement in a ball mill, it is sometimes impractical to grind finer in a dry state. Even though the chemical reactivity requires the material to be dry ground, it is sometimes necessary to use different breakage machines to obtain the product, but it is usually more expensive, requires more energy and reduces capacity. The economic alternative is to use a grinding aid. Grinding aid or grinding additives refer to substances which when mixed into the mill contents cause an increase in rate of size reduction and flowability. Grinding process of clinker was carried on with a laboratory scale ball mill by varying different type of grinding additives and dosage while the operating conditions of the mill was kept constant. These additives were added into mineral in certain ratio based on the mineral weight and the grinding has been done for a definite time at the same condition. Analysis were then conducted for their size distribution and compaction factor. Results shows that there were significant improvement in size distribution as the dosage and types of grinding additives changes. Different types of grinding additives were found only suitable for clinker grinding while other give no significant results. The results obtained showed that with the addition of grinding additives can improve the grindability by decreasing agglomeration and increase breakage and hence, reducing ball coating Industrials application of grinding additives also give significant improvement in terms of throughput and size distributions.

Mineralogical Characteristics and Quantification of Mineral Phases in Malaysian Low Grade Manganese Ore

The aim of this work is to study the quantification of crystalline and amorphous content of manganese ore. The mineralogical characteristics and mineral phases of Malaysian low grade manganese ore are investigated using spiking method technique. Manganese ore was mixed with an internal standard of rutile and analyzed by Rietveld refinement with SIROQUANT. The refinement qualification and quantification indicated three phases which are pyrolusite (MnO2) with 1.1%, goethite (α-FeOOH) with 0.5% and quartz (SiO2) with 30.9%. From the calculation, sample consisted more amorphous content which is 0.6 compared to crystalline (0.4). This revealed that the ore is in amorphous form.

Chemical and Mineralogical Characterization of Malaysian Low Grade Manganese Ore

This paper aims to chemically and mineralogically characterize the Malaysian low grade manganese ore (LGMO). The optical microscope, and scanning electron microscope (SEM) fitted with an energy-dispersive x-ray analyzer (EDX) were used for ore morphology assessment, mineral liberation analysis, particle texture studies, grain size distribution and mineral association assessment. X-ray fluorescence (XRF) and X-ray diffraction (XRD) were used to determine the LGMO’s composition and to identify mineral phases, respectively. SEM images with EDX analysis revealed various optical characteristics of the ore, while XRF results showed that the major elements present in this LGMO are Si, (16.95%), followed by Mn, Fe and Al (at 13.17%, 4.63% and 4.70%, respectively). Phase analysis by XRD meanwhile, revealed the presence of α-quartz, pyrolusite and aluminum-substituted goethite. The natural grain-size distribution and texture (observed using optical and backscattered image analysis) revealed that manganese liberation was observed at particle sizes below 150 µm. This indicates that particle size has a significant effect in the recovery of the manganese oxide. The data and information obtained from this characterization study will aid in the identification and the design of a suitable treatment method for this local LGMO, and with that, the possibility of exploiting this deposit as a local source of manganese.

Bamboo Sawdust as a Reduction Agent in Leaching Applications: Characterization Studies

One of the promising and environmentally friendly hydrometallurgical processes for the recovery of manganese is acid leaching in the presence of carbohydrate as a reducing agent. The aim of this study is to characterize bamboo sawdust (BSD), in particular, the carbohydrate within, for possible usage as a reduction agent in acid leaching applications. Characterization were done using Malvern analyzer (particle size distribution), SEM (morphology), XRD (crystalline index) and FTIR (molecular framework). Detailed BSD constituents were also analyzed, to determine the cellulose, hemicellulose and lignin content. Results exhibited a wide size range distribution with a span value of 1.86, and geometric mean diameter of ~100 µm. The dominant composition, meanwhile, were cellulose (38.96%) hemicellulose (26.95%) and lignin (25.86%). The morphology characteristic by SEM revealed a smooth fibrous surface with multiple aligned bundles. The assessable crystalline index of cellulose was 56.12%. The molecular framework of cellulose, hemicellulose and lignin were clearly illustrated in BSD. The obtained characteristics are valuable information in utilizing BSD as a source of carbohydrate for leaching application.