Characterization of Flocs in Dewatering of Coal Plant Tailings

Flocculation is a widely used method for dewatering fine coal tailings. Flocs must resist to the shear stresses during the following processes such as flotation, cyclone separation, and pumping. Therefore, the strength of the flocs must be considered during flocculation. In this study, the fine coal tailings were dewatered with an anionic flocculant SNF-923 at various dosages, and the floc size of the coal tailings was characterized using a laser diffraction particle size analyzer with respect to time in order to determine the change in the floc size and hence the floc strength. The results of this study clearly indicated that the determination of the floc size with a laser particle size analyzer could be a simple and good method to observe the flocculation efficiency in terms of the floc strength

Determination of mineral proccesing induced environmental impacts

In this study, the mineral processing, environmental technology and the application of new or improved methods both of mineral processing and the treatment of solid and liquid wastes is discussed, and to provide the appropriate background to apply mineral processing techniques so as to minimize environmental degradation

INVESTIGATION OF RADIOACTIVE CONTENT OF MANISA-SOMA AND ISTANBUL-AGACLI COALS (TURKEY)

Coal, the world's most abundant, most accessible and most versatile source of fossil energy was brought to the forefront of the global energy scene by the industrial revolution of the 19th century. Like any fossil fuel, coal is associated with naturally occurring radioactive materials. This is due to their U, Th, and K content. This certainly has radiological implications not only for the miners but also for the immediate environment of the mines and the users. In this study, the radioactive elements in Manisa-Soma and Istanbul-Agacli coals and their ashes were studied. In the experimental section, the coal and thermal power plant ashes which were taken from Manisa-Soma were used. Sieve, moisture, ash, calorific value, volatile amount, total carbon, total sulphur, major element and radioactive element analysis of the samples were carried out. The float and sink analyse and flotation tests were carried out on the samples which were taken from Manisa-Soma and Istanbul-Agacli. Thus, radioactive elements changes and moving mechanisms were investigated with coal preparation and burning methods. Furthermore, the pre-investigation of the assessment of the thermal power plant ashes was carried out with the experiments on the ash samples, which were taken from the Soma thermal power plant

Investigation of recovery possibilities of rutile minerals from the feldspar tailings with gravity separation methods

In feldspar processing, flotation beneficiation tailings that containing high ratio of titanium minerals emerge at a considerable amount as a result of beneficiation of feldspar reserves with high TiO2 content due to required specifications by global feldspar market. Recovery of titanium minerals from these tailings which can be evaluated as alternative TiO2 resources is an important research topic as they have an important economic potential in terms of unexploited values. Within the scope of this study tailing samples have been taken from a privately owned flotation facility which is operating in Mugla Turkey in order to characterization and investigation of recovery possibilities of titanium minerals from feldspar tailings. Physical, chemical and mineralogical characterization studies and laboratory scaled beneficiation tests with gravity methods have been conducted on these samples. Effects of some parameters on efficiency of beneficiation have been investigated within the scope of beneficiation tests carried out with shaking table and multi gravity separator. As a result of characterization studies, it was determined that feed sample contains TiO2 at the rate of 1.90% and TiO2 content is associated to rutile mineral to a large extent. As a result of beneficiation tests; a concentrate that containing 11.26% TiO2 with a 50.43% rate of recovery were obtained in the shaking table tests and a concentrate that containing 17.11% TiO2 with a 89.33% rate of recovery were obtained in the MGS tests by using optimum conditions. In consideration of results obtained it is presented that gravity methods are able to be used as method of a pre-beneficiation in the recovery of titanium minerals from feldspar tailings

POTENTIAL ADVANCES IN FLOTATION BY USING WATER JETS

Some mineral processing problems are not yet satisfactorily solved by the current technology, especially those based on the use of mechanical energy for comminution and separation. The use of mechanical energy has certain inherent drawbacks such as wear of machinery components and limitation in the speed of moving parts to avoid risk of failure under the severe working conditions encountered in the industrial processes. Waterjet can contribute to overcoming such disadvantages since it allows to transfer energy without contacts between solid materials (no wear) and it is suitable for generating high velocity streams in air or in water even at relatively low pressures. The potential benefits of waterjet technology are particularly interesting in flotation where the size and speed of the air bubbles, that depend on the shear velocity induced by agitation, arc a critical aspect for the optimization of the separation results (recovery and selectivity) and the reduction of the running cost items (wear and energy consumption)

Determination of surface chemistry and flotation properties of rare earth mineral allanite

In this study, flotation properties of allanite, a sorosilicate rare earth mineral that commonly found in some new complex ore reserves, was studied with EDA (CH3-(CH2)(9)-O-(CH2)(3)-NH2/ethylenediamine), a commercial cationic collector in the etheramine acetate group, and R845N (tetrasodium N-(1,2-dicarboxyethyl-N-octadecyl/octadecenyl sulfosuccinamate), a commercial anionic collector in the alkyl succinamate group. In this context, firstly micro-flotation studies were carried out using a pure crystalline allanite specimen. In accordance with micro-flotation studies; zeta potential, contact angle, and bubble-particle attachment time measurements were also carried out to investigate the surface properties of allanite mineral. Conventional flotation experiments were also carried out under the conditions determined in the surface chemistry studies. The micro-flotation experiments showed that the flotation recovery increased up to approximately 93.00% and 48.50% at 100 ppm for EDA and R845N, respectively. A strong relationship between flotation recovery and bubble-particle attachment time were observed. The zeta potential and contact angle values of the allanite sample increased with the increasing concentrations for both collectors which indicated a successful collector adsorption onto allanite surface. Moreover, a correlation between the results of flotation recovery, contact angle and zeta potential measurements was also determined. Thus, a significant contribution was achieved in terms of understanding the micro-flotation results. The results of conventional flotation were consistent with the micro-flotation results as the FREE grade of the floated fractions were 0.59% and 0.99%, and the recovery rate of floating fractions were 81.39% and 64.24% for EDA and R845N, respectively. The obtained results clearly demonstrated that R845N, a collector of the alkyl succinamate class, can be used for selective separation of allanite from the other silicate gangue minerals

Evaluation of digital image processing (DIP) in analysis of magnetic separation fractions from Na-feldspar ore

Combination of flotation and magnetic separation methods is widely used for enrichment of feldspar ores by purifying from dark-colored gangue minerals such as iron and titanium. In this study, the removal of dark-colored minerals from feldspar ore (Aydin Cine region of Turkey) was studied using a dry magnetic separator. The effect of several parameters such as feed particle size, blade angle, and roll speed on the removal efficiency was investigated in detail. In addition, the gangue contents of the magnetic and non-magnetic products were determined by a digital image processing (DIP) method in terms of using color differences between the feldspar sample and gangue minerals. The results obtained from this study clearly indicated that the dry magnetic separation method can be successfully applied in enrichment of feldspar. Meanwhile, the particle size of the sample showed no significant influence on the separation recovery. According to the results obtained from the digital image processing process, the sample with 0.04% cross sectional area of dark-colored minerals can be obtained at roll speed of 100 rpm and 130 degrees of blade angle using the original particle size of 500x106 mu m. Additionally, most importantly, these results showed that digital image processing method can be used to determine gangue content (dark-colored minerals) of the magnetic separation products compared to conventional methods as a simple, a reliable, and a repeatable method

BENEFICIATION OF LOW-GRADE FELDSPAR ORE USING CYCLOJET FLOTATION CELL, CONVENTIONAL CELL AND MAGNETIC SEPARATOR

In order to increase the quality of feldspar ore and to obtain sellable feldspar concentrate, it is necessary to remove coloring impurities such as iron and titanium contained in it. For the removal of coloring minerals from feldspar ore the most widely used method is reverse flotation method. Reverse flotation process is generally carried out in conventional mechanical cells. In this study, it was aimed to enrich low-grade feldspar by using cyclojet flotation cell which was developed as an alternative to conventional cell. Then, experiments were performed by using conventional cell and wet magnetic separator and the results were compared with the flotation results obtained by using cyclojet cell. In experimental studies, 200 micrometer grain sized feldspar (albite) ore obtained from Mugla province at the west side of Turkey was used. It was detected that the sample was containing 0.100% Fe2O3 and 0.360% TiO2 as coloring minerals. Cyclojet cell, conventional cell and magnetic separator reduced the Fe2O3 content down to 0.010%, but TiO2 content was different in the concentrates obtained by different devices. There was almost no reduction in TiO2 content by magnetic separation method. Cyclojet cell reduced TiO2 content down to 0.030% and mechanical cell reduced TiO2 content down to 0.020%. The weights of the concentrate were detected as the highest (92.70%) in magnetic separator and as the lowest (75.40%) in cyclojet cell. Therefore, it is possible to say that cyclojet cell can compete with mechanical cell and removal of TiO2 in cyclojet cell is much better than the removal of TiO2 in magnetic separator. Generally, in the flotation process performed by using a reagent of Aero801 and Acro825 mixture in natural pH medium, both Fe2O3 and TiO2 can be removed at a rate of up to 90%, but magnetic separator can only remove Fe2O3 mineral

Investigation of flocculation properties and floc structure of coal processing plant tailings in the presence of monovalent and divalent ions

Low-rank coals are generally processed with wet methods including washing, flotation, etc. Fine-sized tailings of these processes are discharged to tailing ponds with a significant amount of associated water which contains a high amount of dissolved ions. These tailings should be dewatered employing coagulation/flocculation in terms of technological and environmental aspects. In this study, the coagulation/flocculation behavior of coal processing plant tailings obtained from Manisa, Turkey was investigated in the presence of monovalent (Na+, K+) and divalent (Mg2+, Ca2+) ions and an anionic flocculant (SPP-600). First, the coagulation properties of coal tailings were determined. Then, the flocculation experiments were carried out, and the turbidity values of the suspensions were measured. Moreover, the sizes of the flocs were determined using a laser diffraction particle size analyzer to analyze the strength of the flocs. The results of the coagulation experiments showed that while divalent ions were more effective at 10-1 mol/dm3, higher settling rate and lower turbidity values were obtained in the presence of monovalent ions at 1 mol/dm3 concentration. The optimum flocculant dosage was obtained as 150 g/Mg from the flocculation experiments. The floc size and strength measurements indicated that the larger flocs were obtained with Na+ than Ca2+ in the presence of the flocculant. The strongest flocs were obtained at 10-1 mol/dm3 Ca2+ + 150 g/Mg flocculant. It can be concluded from this study that the coagulation followed by the flocculation method can be employed to obtain fast flocculation behavior and low turbidity for the dewatering of coal tailings