Kaolin Concentration Research Articles

Rheological, mechanical, and morphological behaviour of polypropylene composites reinforced with ultrafine kaolinite particles

To develop charge/matrix interactions and improve the rheological, mechanical, and morphological performances of the matrix polypropylene, PP/kaolinite composites were prepared using the melt intercalation method at 190 °C. The rheological and mechanical properties of polypropylene/kaolin composites have been evaluated at various concentrations of untreated and/or treated kaolin. It was shown that the melt flow index (MFI) varies visibly but slightly compared to that of the matrix with increasing kaolin content. Furthermore, when the kaolin loading is enhanced, the apparent shear viscosity (ηapp) of the composites increases compared to the matrix and decreases with the increase in the shear rate (γapp). Also, while the shear stress (τapp) is reduced, the flow curve shifts upwards with increasing the kaolin concentration. The systems obeyed the power-law model in shear stress-shear rate variations and were shear thinning as power-law index (n) values increased with kaolin content. Moreover, the mechanical properties of the obtained composites were significantly affected by the dispersion of the filler into the matrix and by the weak interactions at the interface PP/kaolinite. SEM micrographs show a poor dispersion of the nanoclay within the polypropylene matrix and the formation of agglomerates with different sizes.

Preparation and Application of Amino-Terminated Hyperbranched Magnetic Composites in High-Turbidity Water Treatment.

In order to separate the colloidal in high-turbidity water, a kind of magnetic composite (Fe3O4/HBPN) was prepared via the functional assembly of Fe3O4 and an amino-terminal hyperbranched polymer (HBPN). The physical and chemical characteristics of Fe3O4@HBPN were investigated by different means. The Fourier Transform infrared spectroscopy (FTIR) spectra showed that the characteristic absorption peaks positioned at 1110 cm-1, 1468 cm-1, 1570 cm-1 and 1641 cm-1 were ascribed to C-N, H-N-C, N-H and C=O bonds, respectively. The shape and size of Fe3O4/HBPN showed a different and uneven distribution; the particles clumped together and were coated with an oil-like film. Energy-dispersive spectroscopy (EDS) displayed that the main elements of Fe3O4/HBPN were C, N, O, and Fe. The superparamagnetic properties and good magnetic response were revealed by vibrating sample magnetometer (VSM) analysis. The characteristic diffraction peaks of Fe3O4/HBPN were observed at 2θ = 30.01 (220), 35.70 (311), 43.01 (400), 56.82 (511), and 62.32 (440), which indicated that the intrinsic phase of magnetite remained. The zeta potential measurement indicated that the surface charge of Fe3O4/HBPN was positive in the pH range 4-10. The mass loss of Fe3O4/HBPN in thermogravimetric analysis (TGA) proved thermal decomposition. The -C-NH2 or -C-NH perssad of HBPN were linked and loaded with Fe3O4 particles by the N-O bonds. When the Fe3O4/HBPN dosage was 2.5 mg/L, pH = 4-5, the kaolin concentration of 1.0 g/L and the magnetic field of 3800 G were the preferred reaction conditions. In addition, a removal efficiency of at least 86% was reached for the actual water treatment. Fe3O4/HBPN was recycled after the first application and reused five times. The recycling efficiency and removal efficiency both showed no significant difference five times (p > 0.05), and the values were between 84.8% and 86.9%.

Optimum conditions for high-speed solid-liquid separation by ballasted flocculation.

In the ballasted flocculation, high-speed sedimentation of suspensions is achieved using a microsand as a ballast material and a polymer flocculant combined with microflocs made of polyaluminum chloride (PAC) as an inorganic coagulant. In this study, three turbid water samples containing kaolin clay (kaolin concentration: 20, 200, and 500 mg/L) were treated by coagulation-sedimentation and ballasted flocculation. The effects of pH and PAC dosage, which are the controlling parameters for coagulation, and the microsand (silica sand) and polymer dosages, which are the controlling parameters for ballasted treatment, on the treatment efficiency and floc settling velocity were examined. The floc settling velocity under the optimum conditions was 17 times higher than that of the conventional coagulation-sedimentation process using PAC. The turbidity was 0.54 turbidity unit (TU) (TU as the kaolin standard), and its removal efficiency was 99.7%. Furthermore, turbid water samples with different kaolin concentrations (20 and 500 mg/L) were treated via the ballasted flocculation. In this study, fundamental information on the optimization of each dosage condition of coagulant, ballast, and polymer and pH condition in ballasted flocculation was obtained, and the removal mechanisms under optimal, underoptimistic and overoptimistic conditions were proposed.

Flocculation performance of PCFA composite coagulant for removing nanoparticles

In this study, red mud was used as the main raw material to prepare polyaluminum-ferric chloride (PCFA) with high added value. The effects of the liquid–solid ratio, reaction temperature, reaction time, hydrochloric acid concentration during acid leaching, polymerization time, OH−/Fe molar ratio, and polymerization temperature on the preparation of PCFA were investigated and determined by conducting single-factor optimization experiments under optimal preparation conditions. Characterization results show that the surface of the PCFA flocculant has compact and dense porosity and a dense sheet-like structure, and PCFA contains hydroxyl-bridged iron–aluminum polymers. When the settling time was 30 min, the stirring intensity was 200 rpm; the initial concentration of Nano-titanium dioxide（TiO2-NPs） was 30 mg·L−1; the pH value was 7.0; the dosage of PCFA was 25 mg·L−1, and the optimum removal rates of TiO2-NPs and turbidity were 84.8% and 81.3%, respectively. The flocs produced by PCFA treatment of TiO2-NPs were large and dense. Under optimal flocculation conditions, the average particle size of PCFA-TiO2-NP flocs was 2.98 µm, and the fractal dimension was 1.66. Based on the abovementioned flocculation experimental data, a Grey correlation method was established to evaluate the degree of correlation among factors such as ionic strength, settling time, stirring strength, kaolin concentration, initial concentration, reaction pH value, and dosage and the performance of PCFA coagulation to remove TiO2-NP-containing wastewater. In the reaction system of the PCFA coagulation of TiO2-NPs, the dosage is the most important factor.

3D bioprinting of complex tissue scaffolds with in situ homogeneously mixed alginate-chitosan-kaolin bioink using advanced portable biopen

Control of in situ 3D bioprinting of hydrogel without toxic crosslinker is ideal for tissue regeneration by reinforcing and homogeneously distributing biocompatible reinforcing agent during fabrication of large area and complex tissue engineering scaffolds. In this study, homogeneous mixing, and simultaneous 3D bioprinting of a multicomponent bioink based on alginate (AL)-chitosan (CH), and kaolin was obtained by an advanced pen-type extruder to ensure structural and biological homogeneity during the large area tissue reconstruction. The static, dynamic and cyclic mechanical properties as well as in situ self-standing printability significantly improved with the kaolin concentration for AL-CH bioink-printed samples due to polymer-kaolin nanoclay hydrogen bonding and cross-linking with less amount of calcium ions. The Biowork pen ensures better mixing effectiveness for the kaolin-dispersed AL-CH hydrogels (evident from computational fluid dynamics study, aluminosilicate nanoclay mapping and 3D printing of complex multilayered structures) than the conventional mixing process. Two different cell lines (osteoblast and fibroblast) introduced during large area multilayered 3D bioprinting have confirmed the suitability of such multicomponent bioinks for in vitro even tissue regeneration. The effect of kaolin to promote uniform growth and proliferation of the cells throughout the bioprinted gel matrix is more significant for this advanced pen-type extruder processed samples.

Potential of Local Clay for the Development of Limestone Calcined Clay Cement in East Java

Limestone Calcined Clay Cement (LC3) offers an innovative and sustainable alternative to traditional binders, utilizing calcined clay and limestone as partial substitutes for Ordinary Portland Cement (OPC) clinker. This study investigated the potential of local clays found in East Java, Indonesia, for LC3 production. Clay samples from three sites in East Java, with pure kaolin as a benchmark, were assessed. A formulation with 50% OPC clinker substitution was employed, integrating limestone powder, calcined clay, and gypsum. The clays underwent drying, grinding, sieving, and calcination at both 700°C and 800°C. For comparison, a sample of local Trass, typically used in Portland Composite Cement, was also evaluated. Compared to OPC, the LC3 samples exhibited reduced workability and a faster initial setting time. However, the LC3 mortar displayed commendable compressive strength, achieving a Strength Activity Index exceeding 75% at 28 days. The calcination temperature influenced the ultimate strength, especially in specimens with a higher kaolin concentration. One of the local clays, sourced from Trenggalek, with a kaolinite content of 49%, achieved a compressive strength of 43 MPa at 28 days. This value closely parallels the strengths of both OPC (49 MPa) and the metakaolin (42 MPa) mixtures.

Developing magnetic, durable, agglomeration resistant and reactive copper-based oxygen carrier particles by promoting a kaolin-reinforced, manganese‑iron mixed oxide support

Chemical looping with oxygen uncoupling (CLOU) process, involves the use of two interconnected fluidized bed reactors, where oxygen carrier particles are able to release O2 at the fuel reactor operation conditions. Cu-based oxygen carriers containing a kaolin-reinforced MnFe mixed oxide as magnetic support, were prepared by granulation to improve their oxygen carrier properties by means of a simplified preparation method. A study was performed into the effect of kaolin concentration and calcination temperature on magnetic permeability, crushing strength, attrition, agglomeration resistance, and reactivity. Two oxygen carriers containing 28.5 wt% CuO-5 wt% kaolin and 30 wt% CuO-7.5 wt% kaolin, respectively, and both calcined at 1100 °C, were selected because they maintained their magnetic properties and reactivity after kaolin addition and showed improvement in their mechanical resistance. They were tested in a batch fluidized bed reactor (BFBR) to evaluate their fluidization behaviour. Low attrition rate without any agglomeration phenomena was observed for both of oxygen carriers up to temperature of 950 °C. The material prepared with 7.5 wt% kaolin demonstrated improved mechanical resistance, very low attrition rate and higher CuO utilization for the CLOU process after use in the BFBR, while maintaining reactivity during redox cycles and magnetic properties without agglomeration problems.

Effect of Suspended Solids and Organic Matter in Water on the Removal of ZnO-NPs by Coagulation

Background: Zinc oxide nanoparticles (ZnO-NPs) have been shown to have a non-negligible impact on the environment Objective: Kaolin and humic acid were used in the aqueous environment to study their effects on the removal of ZnO-NPs. Method: In this work, polyaluminum ferric chloride (PAFC)/cationic polyacrylamide (CPAM) coagulants were used together with kaolin and humic acid were used to study their effects on the removal of ZnO-NPs and to analyze their mechanism of action. Results: The results showed that the removal rate of ZnO-NPs in the humic acid system decreased by about 30% compared to that in the pure water system, and increasing the ionic strength and humic acid concentration was not conducive to removing ZnO-NPs. On the other hand, the ZnO-NPs removal rate in the kaolin system was up to 96.28%, and increasing the ionic strength and kaolin concentration contributed to the removal of ZnO-NPs. In the humic acid and kaolin systems, the effects of coagulant dosage and pH on the removal of ZnO-NPs were about the same as in the pure water system. Moreover, 5 mg/L humic acid inhibited floc growth during removal of ZnO-NPs by coagulation with PAFC/CPAM. In contrast, 5 mg/L kaolin promoted flocs growth, resulting in stronger and more stable flocs and a 5.25% increase in the fractal dimension compared to the pure water system. Conclusion: These results suggested that suspended solids and natural organic matter in the water could directly affect the effectiveness of coagulation to remove ZnO-NPs.

Copper oxide nanoparticles removal by coagulation and optimization by matter–element analysis model

Nanoparticles have been inspected in water environment and sewage treatment plants, but how to achieve efficient removal of them through existing treatment processes is a potential issue. In this study, the organic–inorganic composite coagulant (PAC-CA) was applied to remove copper oxide nanoparticles (CuO-NPs) and study their coagulation behavior and the characteristics of flocs produced by coagulation. Under the optimal coagulation conditions with a dosage of 25 mg/L, pH of 7, stirring intensity of 200 s−1, and settling time of 15 min, the removal rates of CuO-NPs and turbidity were 89.83% and 93.51%, respectively. Zeta potential studies show that the main action mechanism of PAC-CA under low dosage or alkaline conditions is charge neutralization, and under high dosage or acidic conditions, the main action mechanism is adsorption bridging. A matter–element analysis model was established based on the evaluation index of stirring intensity, kaolin concentration, humic acid concentration, initial CuO-NPs concentration, pH, PAC-CA dosage, turbidity removal rate, and CuO-NPs removal rate. Kaolin can promote the removal of CuO-NPs and turbidity by PAC-CA. The main action mechanisms of PAC-CA are charge neutralization and adsorption bridging. PAC-CA has good coagulation performance for CuO-NPs wastewater, and provides a theoretical basis for the practical engineering application of coagulation for removing nanoparticles in wastewater.

Role of kaolin on drought tolerance and nut quality of Persian walnut

Global warming has endangered crop production by reducing water availability and increasing temperature. Kaolin may protect plants against these conditions by reflecting the light and decreasing plant temperature. This study was conducted to evaluate the protective effects of kaolin spraying on kernel yield and quality of four walnut cultivars and genotype. The experiment was conducted as a split-plot factorial design in time factor with four factors including irrigation levels (100% and 50% of regular irrigation), kaolin solution concentrations (0, 2.5, 5 and 7.5%), walnut varieties (‘Chandler’, ‘Franquette’, ‘K72’ and ‘SG’) in two consecutive years (2012–2013). By increasing the kaolin concentration under well-watered irrigation, gas exchange, chlorophyll concentration, leaf potassium content, and kernel quality were improved. Moreover, increasing the kaolin concentration reduced sunburn and leaf temperature under different irrigation regimes. Based on results, genotypes ‘K72’ and ‘SG’ showed more severe sunburn symptoms. Water stress and no kaolin application had negative effect on the kernel color. Leaf temperature increased with reducing the irrigation and concentration of kaolin. Under water stress, ‘Chandler’ had the highest relative water content (58.25%) and ‘Franquette’ had the lowest RWC and therefore considered as the most drought sensitive cultivar. The lowest fruits sunburn in ‘Franquette’, was related to the thickness of its fruits’ husk. In general, the foliar application of kaolin 5% and 7.5% alleviated the negative effect of drought stress and improved the walnut kernels quality under water deficit condition by improving chlorophyll content, RWC, and gas exchange and reducing leaf temperature.

Evaluation of efficiency of coagulant obtained from elaborated red sludge from alumina plant

In document, the effectiveness of reducing the chromaticity and turbidity of the Dnipro river water was investigated and estimated by means of existing coagulants Al2(SO4)3·18H2O and FeCl3·6H2O and synthesized coagulant from the red sludge of alumina plants - SC. During the experimental part of the work in the laboratory, the following optimal dosages of coagulants were chosen, namely, 0, 1, 2, 5, 10 mg/dm3 based on Al2O3 and Fe2O3. The volume of samples of the solutions, which were subjected to the study, reached 200 ml. Model solutions of bentonite with a concentration of 100 mg/dm3, sodium humate with a concentration of 16.8 mg/dm3, kaolin concentration of 100 mg/dm3 and natural water of the Dnipro River were used.Based on the analysis of the experimental data obtained, it was found that the alternative coagulant is not inferior to the existing and widely used coagulants.During clearing and discoloration of the Dnipro river waters, the SC showed better results. Therefore, it can be said that obtaining "alternative" coagulants from waste products is a very promising and economically viable direction of research and development of new reagents for water purification and water treatment.

Design of SiO2-TiO2-P(AM-DMC) cationic composite flocculant and optimization of the flocculation process using response surface methodology

At present, the polymer flocculation technology has been widely used in the treatment of oil sand tailings. However, the current composite flocculant still has the problems of low flocculation efficiency and serious secondary pollution after using. In this article, cationic composite flocculant SiO2-TiO2-P(AM-DMC) with self-degrading characteristics was prepared by the surface photoinitiated polymerization technique. Above all, in order to study the synthesis process of SiO2-TiO2-P(AM-DMC), cationic composite flocculant was characterized by FTIR, TG, TEM, XPS, etc. Furthermore, the central composite design (CCD) and response surface methodology (RSM) were used to optimize the preparation parameters of the cationic composite flocculant. And the optimization results of preparation parameters of cationic composite flocculant showed that the optimal preparation parameters of SiO2-TiO2-P(AM-DMC) were as follows: m DMC: m AM = 5, monomer concentration was 35% and reaction time was 100 min. Ultimately, the flocculation parameters of SiO2-TiO2-P(AM-DMC) were optimized by CCD and RSM. Moreover, the optimization results of flocculation parameters of cationic composite flocculant showed that the optimal flocculation parameters of SiO2-TiO2-P(AM-DMC) were as follows: pH = 5, flocculant dosage was 30 ppm, kaolin concentration was 1.36%. In summary, this work had greatly enriched the knowledge of oil sand tailings treatment, and had the extremely important reference significance for realizing the parameter regulation of high-efficiency flocculation of oil sand tailings.

Influence of Kaolin on the Formation and Sedimentation of Oil-Colloidal Particle Aggregates in Marine Environments

Li, J.; Xia, W.; Liu, L.; Zhang, M.; Zhao, B.; Liu, J.; Meng, M.; Zhao, Y., and Guo, J., 2020. Influence of kaolin on the formation and sedimentation of oil-colloidal particle aggregates in marine environments. Journal of Coastal Research, 36(3), 521–527. Coconut Creek (Florida), ISSN 0749-0208.Spilled oil in the marine environment is dispersed into droplets under the action of waves and currents, forming oil-colloidal particle aggregates (OcPAs) in the presence of clay particles in the ocean. Kaolin, which is a typical representative of clay particles, was investigated for its influence on the morphology and sedimentation characteristics of OcPAs in this work. Results have displayed that OcPAs exist mainly in the forms of single drop, double drops, and multiple drops, and their morphology is mainly affected by the turbulence intensity and kaolin concentration in seawater. Furthermore, it is observed that under medium- and high-turbulence intensity, the larger the fractal dimension of OcPAs is, the smaller the settling velocity becomes. The results suggest that the spilled oil can be removed from the sea surface by adding clay particles to promote the formation of OcPAs with large particle size and rapid settling velocity.

Beneficiation of White Kaolinitic Sandstone to Produce Kaolin Concentrate from Wadi Siq-Rakyia Area in Wadi Araba, Jordan

Kaolinitic sandstone samples of Lower Cretaceous from Wadi Siq-Rakyia area in Wadi Araba/south of Jordan were studied and assessed as a source of Kaolin. Three channel samples and a composite bulk sample were studied for their mineralogical, geochemical, and grain size distribution analysis. The aim of this research work was to achieve kaolin concentration by examining the best-suited and cost-effective processing method(s) with appropriate product recovery. Following the initial sample characterisation at “bench scale”, a pilot study was performed on the bulk sandstone sample. Kaolin was accumulated in the fine size fraction (−125 μm) after agitating and wet screening of the sample. The −125 μm size fraction sample was used to produce kaolin concentrate. Hydrocyclone classification was applied in the pilot study for this purpose. The mass flowrate of the feeds and the products in the hydrocyclones was calculated for the bulk sample as well as the amount of water required operating the process. A kaolin-enriched product was produced following the use of hydrocyclones. A kaolin concentrate at a grade of 71% and a recovery of 78% was produced which could be used in the ceramic industry for tableware and sanitaryware.

Preparation of Quaternized Lignin Derived from Oil Palm Empty Fruit Bunches and its Flocculation Properties

Quaternized lignin-based flocculant (QL) was prepared by a single-step reaction of an extracted lignin (EL) derived from oil palm empty fruit bunches (OPEFB) with 3-chloro-2-hydroxypropyl trimethylammonium chloride (CHPTAC) under alkaline condition. The performance of QLs was studied for various β values (molar ratios of CHPTAC to phenylpropanoid unit of lignin), flocculant dosages, pH values, kaolin concentrations, slow mixing rates and sedimentation times. The QL10 achieved the highest turbidity removal efficiency (εt) with increasing flocculant dosage, pH and kaolin concentration to the optimal conditions of 5 mg L−1, pH 7 and 1000 mg L−1, and required 20 min of sedimentation time at all the mixing rates tested. The flocculation kinetics agreed well with the particle collision model. The QL10 has good sludge dewatering properties compared to the alum. It also showed encouraging results in water quality analysis for sewage wastewater flocculation in comparison to that of the alum. This indicates the potential application of QL in treating water and wastewater.

Efficient Removal of TiO2 Nanoparticles by Enhanced Flocculation–Coagulation

TiO2 nanoparticles (TiO2-NPs) in water were removed by enhanced coagulation with polyaluminum ferric chloride (PAFC) and cationic polyacrylamide (CPAM). The flocculation efficiency by PAFC and PAFC/CPAM for three different initial concentrations (0.2, 2, and 30 mg/L) of TiO2 nanoparticles in pure water and a kaolin suspension system (kaolin concentration: 30 mg/L) were investigated with different coagulant dosages, pH values, precipitation times, and hydraulic conditions. Results showed that the removal rate of TiO2-NPs in the kaolin suspension system was slightly higher than that in a pure water system, and the removal rate of TiO2-NPs obtained by PAFC/CPAM was significantly higher than that by PAFC alone. The removal efficiency of TiO2-NPs increased with increased initial concentration of TiO2-NPs. Under the optimal conditions, the removal rates obtained by PAFC/CPAM for 30 mg/L initial concentration TiO2-NPs in pure water and the kaolin suspension system were 97.98% and 98.62%, respectively. Studies on...

Effect of kaolin on floc properties for reactive orange removal in continuous coagulation process.

Magnesium hydroxide was used as a coagulant for treating reactive orange wastewater in a real continuous process. Effects of kaolin on coagulation performance and floc properties were investigated with controlled experiments through floc size distribution, zeta potential, scanning electron microscopy and Fourier transform infrared spectroscopy. Kaolin had significant influence on magnesium hydroxide-reactive orange floc formation and growth. The results showed that average floc size reached 16.31, 12.88 and 20.50 μm, respectively, in the rapid mixer, flocculation basin and sedimentation tank when kaolin concentration was 10 mg/L and reactive orange initial concentration was 0.25 g/L. The floc size tended to increase with the increase of kaolin suspension to 10 mg/L. All of the flocs under investigation showed that floc breakage led to decreased average floc size and remained stable in the flocculation basin. Reactive orange and kaolin could be removed effectively in the continuous coagulation process. Reactive orange was adsorbed in the surface of magnesium hydroxide through charge neutralization and adsorption.

DEPOSITION OF SEDIMENTS IN DETENTION POND

Suspended sediment is the pollutant of primary concern to the urban rivers that results in adverse environmental and economical effect. Detention pond may become the structure that can be indirectly used to remove a portion of suspended sediment. Although the ponds were initially designed to control the increased quantity of runoff associated with impervious areas in the urban landscape, the ponds have been increasingly used to reduce the concentration of contaminants in the runoff. Experiments on deposition of sediments in detention pond and other related aspects such as sediment concentration dispersion and efficiency of the pond were investigated in this study. The kaolin concentration (150 mg/L) has been used as a cohesive sediment material and the range of the discharge is from 0.006 m 3 /s to 0.016 m3 /s. For horizontal distribution, as the diameter of sediment particle is 0.013 mm and particle settling velocity, ωs = 0.8 x 10-4 m/s, the shear flows and settling velocities give an effect of sediment concentration in the detention pond. As the time increases, the sediment concentration decays. The vertical distribution of suspended sediment concentration is uniform according to the small Rouse number at each point. The deposition rates depend on inlet velocity of the pond, an increase from 4.725 x 10-3 g/sec m2 in inlet area to 5.715 x 10-3 g/sec m2 at outlet area. The sediment trap efficiencies of the model is 20 % which is less than the sediment trap efficiency of the prototype due to only cohesive sediment material was used in this experiment

MECHANICAL PROPERTIES OF RUBBER YARN WITH THE ADDITION OF KAOLIN AS A REINFORCING FILLER

Rubber yarns have been made using kaolin and titanium dioxide (TiO 2 ) as fillers on concentrated latex compounds, with kaolin variations of 0, 6, 12, and 15 phr. This research was conducted to find out the result of kaolin concentration analysis on rubber vulcanization. The observed mechanical properties include a modulus of 300%, a modulus of 500%, a breaking tension, and a breaking extension. Kaolin mixed with titanium dioxide (TiO 2 ) has an effect on the mechanical properties of rubber yarn. The higher the kaolin concentration, the mechanical properties of the rubber yarn are getting worse, as it is increasingly away from the standard value set for the rubber yarn. Keywords : Kaolin, rubber yarn, and vulcanization.

EFFECTS OF KAOLIN CONCENTRATION AS FILLER ON VULCANIZATION OF RUBBER YARNS

Abstract. A study has been conducted by mixing kaolin and titanium dioxide (TiO 2 ) used as a filler on latex compounds which have been concentrated in the manufacture of rubber yarns with kaolin variations of 0; 6; 12; 15. This research was conducted to find out the result of kaolin concentration effects on rubber yarns vulcanization. The results showed that the concentration of kaolin mixed with titanium dioxide (TiO 2 ) affect on rubber yarns vulcanization. The higher the concentration kaolin the smaller the swelling, so the time of vulcanization will take longer. Keywords : Kaolin, Rubber Yarns, and Vulcanization