Mixture Of Kaolin Research Articles

Reproducing the inherent variability of soils using a three-dimensional printer

This paper describes a new approach to modelling the three-dimensional (3D) variability of soil by using a multi-material 3D printer to extrude slurries of different types of clays. First, a distribution of the liquid limit in space was obtained using random field theory. Then, a 3D clay printer was developed to reproduce the complex patterns obtained analytically. The 3D clay printer can use eight types of homogeneous soils made from mixtures of kaolin, bentonite and colourant. The next step was fine-tuning of printing velocity and optimal water content for each type of clay. Consolidation involved two stages: use of a rigid plate to impose low stresses followed by use of a flexible membrane to control the stress rather than displacement during the consolidation process. The variability of the sample built-up with the 3D printer was assessed by measuring the undrained strength and electrical resistivity. Then the electrical resistivity was correlated with porosity. The results showed the differences between probability distributions of each soil's properties including liquid limits, electrical resistance, porosity and undrained shear strength. These differences are results of the consolidation process that tends to homogenise the sample and the failure mode of the experimental method used to evaluate the sample.

Effect of water on the thermal properties of argillite – based geopolymers.

This study focuses on the effect of consolidation time and water immersion on the thermal behavior of geopolymers based on mixture of kaolin and argillite calcined at 750 °C. In order to assess the fire resistance water and thermal treatment at 1000 °C were performed. Compressive strength and structural changes of the samples before and after treatment were investigated. It was demonstrated that the age of geopolymer (7, 14 and 28 days of consolidation) does not have a significant effect on strength neither before (22 MPa) nor after (30 MPa) thermal treatment. The results also show that all samples present higher compressive strength ratio (σafter/σbefore ~ 1.4). The geopolymer samples do not exhibit structural variation over the time in agreement with the compressive strength values. The good performance of compressive strength after 1000 °C was due to the formation of the same crystalline phases after heat treatment such as zeolite (4%) and leucite type phases (62%) and wollastonite (18%) which were also evidenced by SEM observations. The decrease of compressive strength after water immersion (16 MPa) and after thermal treatment (19 MPa) was explained by the decrease of arcanite by 70% as well as the amorphous phase content. Nevertheless, leucite (46%) and wollastonite (24%) were formed. In conclusion, the use of mixture of kaolin and argillite calcined at 750 °C leads to water and thermal resistant geopolymers.

Removal of phenol and inorganic metals from wastewater using activated ceramic

Phenol constitutes one of the main pollutants in wastewater. In the present study, adsorption with the use of a cheap alternative bio-filtration medium (activated ceramic, AC) was carried out to remove organic (phenol) and inorganic metals, such as zinc (Zn+2), copper (Cu+2), and lead (Pb+2). Activated ceramic was modified by ozonation with a mixture of crushed coal, Kaolin, and Bentonite, which were thermally treated in a vacuum furnace at temperatures ranging between 300 °C and 600 °C. The volume ratio of crushed coal to Kaolin to Bentonite was 4:6:1. This mixture was mixed with water by the volume ratio of 1:1. The mixture had been exposed to ozone before being used for activation. The pH measurements, chemical analysis, and FT-IR spectra were performed, and textural characterization was obtained. The influence of different parameters including different doses and contact times were investigated. For contact times of between 20 and 120 min, the removal efficiencies of phenol were 23% to 61%, and 56% to 79% with AC amounts of 5 g and 40 g, respectively. The Freundlich and Langmuir isotherm equations were used to explore the adsorption kinetics. The equilibrium data was found to best fit with both models. The use of AC for the removal of phenol showed a high removal efficiency of 85%, whereas the AC removes 67%, 59%, and 41% of Pb+2, Cu+2, and Zn+2, respectively.

Role of addition of kaolin on the firing of white clay for Korean porcelain

ABSTRACT The objectives of this study were to examine the role of the addition of kaolin on the firing of white clay for Korean porcelain by characterizing the fired composites at 1000–1300°C, and finally to estimate the production conditions of ancient Korean white porcelain in the Joseon Dynasty. Yanggu white clay disks composed of 57.1 wt% quartz and 38.8 wt% muscovite showed bloating phenomenon at temperatures over 1175°C due to the evolution of gas incorporated in the disk. Potassiumfrom muscovite (KAl2(AlSi3O10)(F,OH)2) in Yanggu white clay played a significant role as melting agent to form a liquid phase. To produce Korean white porcelain at temperatures over 1175 oC without bloating, the addition of 20–40 wt% of Korean kaolin to Yanggu white clay was necessary. Increasing the amount of kaolin added and firing temperature enhanced the formation of mullite. We estimated the manufacture of a portion of the old Korean white porcelains in the Joseon Dynasty from mixtures of Yanggu white clay and kaolin to improve the refractoriness and whiteness of the body.

Optimization of Hydrothermal Temperature and Time Parameters in the Synthesis of Hierarchical ZSM-5 from Kaolin by Taguchi Method

Hierarchical ZSM-5 was successfully synthesized by hydrothermal crystallization of kaolin clay. A statistical experimental design Taguchi method with analysis of variance (ANOVA) with an L9 Orthogonal array (OA) was used to optimize the formation of high mesoporosity in hierarchical ZSM-5. Samples from kaolin mixtures crystallized at 80-175°C for 12, 24 and 48 h, respectively using hydrothermal followed by addition of mesoporogen cetyltrimethylammonium bromide (CTABr) surfactant. The presence of pentasil zeolite groups and large mesopores surface area and pore volume has observed on the samples by FTIR and N2 adsorption-desorption technique.The optimum synthesis conditions studied by Taguchi analysis based on S/N ratio for temperature and time of hydrothermal. The optimum condition was 127.5°C and 48 h giving the highest mesoporosity. Data analysis of interaction plot for S/N ratio showed there was interaction between temperature and time in the crystallization of hierarchical ZSM-5. Hydrothermal temperature was the most influencing factors for the formation of hierarchical ZSM-5 with a percent contribution of 83%.

Partial seawater desalination treatment for improving chalcopyrite floatability and tailing flocculation with clay content

The declining grades of copper ore associated with the additional processing of clay-based minerals and the use of seawater are problems that copper mining companies are currently facing, where froth flotation and tailing management operations become challenging for operators. In both cases, the detrimental effect is intensified by the presence of calcium and magnesium ions in seawater and their precipitation under alkaline conditions. This research proposes a partial seawater desalination treatment to improve the flotation and thickening performance in clay-containing ore. The proposed seawater treatment promotes the removal of calcium and magnesium ions using carbon dioxide gas and a sodium hydroxide solution. Flotation tests were conducted in a batch cell using synthetic minerals composed of mixtures of chalcopyrite, kaolin, and quartz. Meanwhile, tailings settling assays were performed in a PTFE 30 mm turbine type stirrer with an in-situ characterization of aggregates (using a focused beam reflectance measurement (FBRM) probe). The results showed an improvement in flotation and flocculation performance when tests were carried out with treated seawater at pH > 10.5, where the copper recovery increased from 82% to 95%, compared to seawater without salt removal; meanwhile, the settling rate of flocculated tailing increased from 5.0 m/h to 11.5 m/h. As expected, the sedimentation outcomes showed a clear relationship with the aggregate size. In this context, the partial seawater desalination treatment could be a promising alternative to face the challenges generated by clays and seawater for copper mining companies.

High-efficiency extraction of aluminum from low-grade kaolin via a novel low-temperature activation method for the preparation of poly-aluminum-ferric-sulfate coagulant

A facile hydrometallurgical method was proposed for high-efficiency extraction of aluminum at low activation temperature from low-grade kaolin involving sulfuric acid assisted activation followed by water leaching. After the slurry mixture of low-grade kaolin and sulfuric acid solution was stirred at 25 °C for 3 h and further heated at 150 °C for 2 h, the optimal extraction efficiencies of Al (98.8%) and Fe (98.1%) were achieved via water leaching at room temperature. The activation mechanism was proposed via investigating the intermediates during the activation process. It was found that the low activation temperature and the high extraction efficiencies result from the intercalation of sulfuric acid. The poly-aluminum-ferric-sulfate (PAFS) coagulant was further obtained from the leachate, and its coagulation performance was evaluated by jar tests. It was found that the PAFS is highly effective under acid conditions, and shows the highest removal efficiency of 93.7% for Direct Blue 2B with a dosage of 140 mg/L. Furthermore, the leaching residue was also utilized to prepare silica for rubber compounding ingredients to make full use of the silicon in low-grade kaolin, and simultaneously reduce the discharge of waste. Moreover, the corresponding scale-up experiments and the extended experiments showed that the Al extraction efficiencies of the diasporic bauxite and the spent fluid catalytic cracking catalyst reach 95.4% and 97.2%, respectively via the proposed method. This work provides a new highly efficient Al extraction strategy from low-grade kaolin and other similar ores and wastes containing rich Al element to prepare Al–Fe coagulant.

Consolidation Characteristics of Artificially Structured Kaolin‐Bentonite Mixtures with Different Pore Fluids

The consolidation characteristics of kaolin, bentonite, their mixtures, and natural clays have been widely evaluated. However, the effect of pore fluid on the consolidation characteristics of artificially structured kaolin‐bentonite mixtures should be more investigated. In this study, the oedometer tests were carried out on mixtures of kaolin with 10%, 20%, and 30% bentonite reconstituted with distilled water and 1 M NaCl. The testing samples with an “artificial structure” were prepared using the preconsolidation procedure. The test results show that bentonite greatly affects the consolidation behavior of mixture samples, especially when the pore fluid is distilled water. In the case of distilled water, the addition of bentonite to kaolin clay significantly increased the compression index (Cc), swelling index (Cs), and coefficient of volume change (mv). In this case, the mv of mixture samples increased significantly at low effective axial stress (σ′a) levels (less than the preconsolidation pressure) and then decreased as the σ′a further increased. In the case of 1 M NaCl as the pore fluid, the Cc, Cs, and mv slightly changed with the increase of bentonite content. The research results also confirmed that the effect of saline water on the compression index was noticeable when the liquid limit of soil with distilled water was higher than 110%, and the compression index of soil with distilled water was higher than 1. Regarding the coefficient of consolidation (Cv), the Cv of kaolin sample increased as the σ′a increased, and this trend was independent of the pore fluid chemistry. By contrast, the Cv − σ′a trend of mixture samples depended not only on the pore fluids but also on the stress level.

Preparation of novel porous ceramic microfiltration membranes from fly ash, kaolin and dolomite mixtures

In the present work, low-cost ceramic membranes were prepared by using kaolin (KA), fly ash (FA) and dolomite. The effects of sintering temperature and raw materials composition (i.e., 0–100 wt% of KA in the mixture of KA + FA) on the membrane properties (strength, porosity, pore size, permeability, etc.) were studied. The raw material mixtures were subjected to TGA and the prepared membranes were characterized by SEM, XRD, liquid permeation, mechanical strength and chemical stability tests. The SEM analysis evidenced that the membranes were free of defects and had homogeneous surface structure with evenly distributed pores of similar sizes. A sintering temperature of 900 °C was found to be optimum for both kaolin-based and fly ash based membranes. Addition of 20% dolomite provided sufficient porosity to all membranes (28–51%). The porosity, strength and stability increased, while the pore diameter decreased with an increase in the kaolin content (M0–M100). The sintered mixture with a kaolin content of 75% (M75) was identified as the best membrane among others based on the pore characteristics (mean pore diameter 0.62 μm and porosity 46.3%). When applied to oil-water separation, M75 showed excellent filtration performance with good separation efficiency (up to 97.4% for 100 mg/L oil and up to 98.8% for 200 mg/L oil). The average permeate quality obtained at 1.03 bar pressure difference was found to be within the safe discharge limit (<10 mg/L). Although, the permeate flux declined steadily with time, it has been recovered through membrane regeneration. Model fitting to the flux data indicated the formation of a cake layer because of concentration polarization at the membrane surface during dead-end filtration.

Remediation of cadmium-contaminated soil with biochar simultaneously improves biochar’s recalcitrance

Biochar sequesters cadmium (Cd) by immobilisation, but the process is often less effective in field trials than in the laboratory. Therefore, the involvement of soil components should be considered for predicting field conditions that could potentially improve this process. Here, we used biochar derived from Spartina alterniflora as the amendment for Cd-contaminated soil. In simulation trials, a mixture of kaolin, a representative soil model component, and S. alterniflora-derived biochar immobilised Cd by forming silicon-aluminium-Cd-containing complexes. Interestingly, the biochar recalcitrance index value increased from 48% to 53%–56% because of the formation of physical barriers consisting of kaolinite minerals and Cd complexes. Pot trials were performed using Brassica chinensis for evaluating the effect of S. alterniflora-derived biochar on plant growth in Cd-contaminated soil. The bio-concentration factor values in B. chinensis were 24%–31% after soil remediation with biochar than in control plants. In summary, these results indicated that soil minerals facilitated Cd sequestration by biochar, which reduced Cd bioavailability and improved the recalcitrance of this soil amendment. Thus, mechanisms for effective Cd remediation should include biochar-soil interactions.

Effect of dispersant on the tangential adhesion strength between clay and metal for EPB shield tunnelling

When Earth Pressure Balance (EPB) shields pass through clayey ground, the working tool is frequently clogged, causing a low tunnelling rate and accelerating cutter disk abrasion. Clay clogging is considered to be due to the high tangential adhesion strength between the clay and metal. This paper investigates the changes in the tangential adhesion strength with the consistency index under different total normal stresses and with different dispersant contents using a mixture of bentonite and kaolin (mass ratio of 1:1). The results showed that the tangential adhesion strength first decreased significantly and then remained almost constant with an increase in water content. Injection of the dispersant could decrease the tangential adhesion strength of clay. The tangential adhesion strength decreased gradually with a lower dispersant content (<4%) and then remained nearly unchanged. The tangential adhesion strength increased slowly with a consistency index lower than 0.5–0.6 and then increased significantly. Considering the effect of dispersant on the Atterberg limits of clay, the tangential adhesion strength between the soil and metal with different dispersant contents was virtually identical at the same consistency and under a normal stress. The tangential adhesion strength showed an exponential relationship with the normal stress and consistency index when the consistency index of clay was lower than 1. The reduction of average tangential adhesion strength showed a linear increase as that of liquid limit increased. The slope of the line increased when the normal stress increased. These results indicate that changes in the liquid can represent the effect of dispersant on the adhesion of clay. From the test results, it can be considered that a supporting medium with a consistency index lower than 0.5 is suitable for EPB shields. Since soil with a consistency index lower than 0.4 is easily squeezed out of a screw conveyor, a supporting medium with a consistency index of 0.4–0.5 is ideal for EPB shields, which is in agreement with the conclusion proposed by Hollmann and Thewes.

Synthesis of Sodalite from Indonesian Kaolin with Conventional and Alkali Fusion Method

Sodalite has been synthesized from Indonesian kaolin. Kaolin was converted into more reactive metakaolin using conventional and alkali fusion methods. In the conventional method, kaolin is calcined at a temperature of 700 °C for 3 hours. Meanwhile, in the alkali fusion method, the mixture of kaolin and NaOH was calcined at a temperature of 600 °C for 2 hours. The effect of synthesis parameters such as aging time and crystallization temperature was investigated in conventional methods. Besides that, the crystallization time was investigated in the alkali fusion method. Transformation of kaolin into metakaolin and synthetic products was characterized using X-ray diffraction (XRD), X-ray Fluorescence (XRF), Fourier Transform Infrared (FTIR) and Scanning Electron Microscopy (SEM). The results showed that the kaolin structure contained a lot of quartz. In the conventional method, the kaolin structure cannot be converted into metakaolin. The synthesis product obtained from this method is a mixture of sodalite and quartz. Whereas, in the alkali fusion method, kaolin can be converted into metakaolin and sodium silicate. The synthesis product obtained is a pure sodalite.

Oedometric Behavior of Diatomite–Kaolin Mixtures

AbstractThis paper discusses the results of an experimental program to study the compressibility of mixtures of kaolin and diatom microfossils, particularly the effects of diatomite content (DC) on...

Preparation of glass-ceramic materials using kaolin and oil well drilling wastes

The high production of drill cuttings during oil well drilling operations is one of the main causes of the huge amount of waste created by the oil industry. Meanwhile, large amount of kaolin waste is produced during the kaolin mining processes. These wastes are usually deposited in landfills with no specific use. Thus, recycling of solid wastes by their incorporation in ceramics has been considered an attractive way to obtain high added value technical solutions, enhancing the culture of reuse. Glass-ceramics have been receiving this same approach with the advantage of obtaining a high-performance product from recycled raw materials. The current study proposes the synthesis of glass-ceramics of the SiO2-Al2O3-CaO-Na2O-K2O-MgO system from a mixture of kaolin and oil well drilling wastes. A mixture of the recycled raw materials (wastes) and Na2CO3 (a commercial material used to adjust the glass composition) was melted at 1500 °C for 1 h to obtain a glass-ceramic precursor material. The resulting vitreous powder was studied by thermal, chemical and structural characterization techniques, pressed into pellets and further sintered at 850 °C. The microstructural analysis of the obtained glass-ceramics showed the attainment of dendritic-like crystals combined with an amorphous phase.

Investigation of kaolin–quartz mixtures during heating using thermodilatometry and DC thermoconductometry

Temperature dependencies of the DC conductivity of mixtures of kaolin and quartz were measured in the temperature range of 20–1200 °C. During heating, several processes take place in the sample—release of the physically bound water (PBW), dehydroxylation of kaolinite, the α → β transition of quartz, and the creation of Al–Si spinel. These processes were studied using differential thermal analysis, thermogravimetry, thermodilatometry, and DC conductivity measurement. At temperatures < 200 °C, H+ and OH− ions are the dominant charge carriers in the DC conductivity due to the release and dissociation of PBW. After the release of PBW, and up to the start of dehydroxylation (~ 500 °C), the DC conductivity is dominated by the transport of Na+ and K+ ions. During dehydroxylation, OH− ions, which are released from the kaolinite lattice, contribute to the DC conductivity. However, the association of OH− ions with mobile alkali metal ions into neutral complexes, as well as depletion of OH− source, results in a deceleration of the increase in the DC conductivity at 500 °C. After the dehydroxylation is completed, alkali metal ions become again the dominant charge carriers. At temperatures above the dehydroxylation region, the DC conductivity slightly decreases with the increasing quartz content. A narrow peak of the DC conductivity observed at 960 °C can be linked to the motion of Al3+ cations into new sites as the metakaolinite collapses. The DC conductivity of different mixtures did not differ significantly. Quartz and grog have lower conductivities than kaolin. Thus, the conduction was determined by the kaolin matrix (60 mass%).

Uncertainty in the estimation of hysteresis of soil–water characteristic curve

The soil–water characteristic curve (SWCC) contains key information on unsaturated soil properties and is reported to be hysteretic (i.e. the amount of water at a given suction during the wetting process is less than that during the drying process). In this paper, an equation for quantifying the hysteresis of SWCC due to the ‘ink bottle’ effect is derived. The derived equation shows the uncertainty in the estimated wetting SWCC. In this paper, an equation for quantifying the hysteresis of SWCC due to the ‘ink-bottle’ effect is derived. The derived equation shows the uncertainty in the estimated wetting SWCC. In addition, an equation for estimating the hysteresis of SWCC due to the entrapped air is also proposed. The uncertainty of the entrapped air volume for the compacted mixture of sand and kaolin is analysed using the statistical method. The uncertainty of the entrapped air volume is incorporated into the proposed equation for estimation of the wetting SWCC. Consequently, the equations for estimation of the wetting SWCC due to the ink bottle effect and the entrapped air are proposed and the uncertainty of the estimated wetting SWCC is also presented. The proposed equation is then verified using experimental data measured in this study and published data from literature. The uncertainty in the estimated wetting SWCC (or the hysteresis of SWCC) agrees with the data obtained from the experiments conducted in this study.

Comprehensive Correlations Between the Geotechnical and Seismic Data Conducted via Bender Element

Bender element (BE) is a useful seismic tool to predict the geotechnical soil properties using empirical correlations. However, there were uncertainties in the correlation equations which were not discussed in detail. In this study, the seismic data was thoroughly investigated to improve the correlations with the physical soil properties. Several proportions of sand–kaolin mixtures were compacted, sheared, as well as BE tested. The results showed curve relationships whereas the highest seismic wave velocity and the highest shear strength were attained at the proportion of 40% fine content. At this point, the void ratio, intergranular void ratio, maximum dry density, and specific gravity were 0.43, 1.43, 1.79 g/cm3, and 2.585 respectively. In addition, a direct positive linear relationship between the seismic wave velocity with cohesion (c) and shear strength (τ) provided highest values of seismic velocities at 53.7 kPa and 81.7 kPa of c and τ respectively. However, the seismic wave velocity less significant effected by the friction angle. The paper presented 68 empirical correlation equations between the previous parameters. The comparison with previous researchers indicated that the application of the empirical correlation equations was limited to the material type (clay and sand), fine content range (20–70%), void ratio range (> 0.43), and condition of the samples.

Effect of heavy metal contamination on the plasticity of kaolin-bentonite clay mixtures and an illite-smectite rich natural clay

The behaviour of soil is complex in a natural environment. Contamination of soil with organic and inorganic contaminants may change the properties of soil. Recent studies have shown that the heavy metal contaminants affect the plasticity and consolidation behaviours. However, little is known about the effects of heavy metals on the behaviour of different types of clay, especially how clay behaves when multiple heavy metals are present in clay. The paper will present results from tests on the effect of three different heavy metal ions used separately, and mixed together in combinations, on the liquid limit (wL), plastic limit (wP) and plasticity index (PI) of kaolin, bentonite, mixtures of kaolin and bentonite and reconstituted Lucera clay. It is found that plasticity index of bentonite is reduced significantly with the addition of heavy metals while PI increases slightly in kaolin. A 1:1 clay mixture of kaolin and bentonite showed significant reduction, while reconstituted Lucera clay has shown small reduction with the addition of heavy metals. It is found that at higher concentrations of copper and zinc cations, the effect takes reverse trend on the liquid limit of kaolin and similar behaviour was observed on the bentonite at higher concentrations of lead ion. Interestingly, lead ion exhibited a significant effect on the plasticity of bentonite when tested with NaCl solution as pore fluid.

Preparation mullite/Si3N4 composites by reaction spark plasma sintering and their characterization

In the present study, in-situ mullite/Si3N4 composites were prepared successfully by reaction spark plasma sintering. For this purpose, 5, 10 and 15 wt% of Si3N4 were added to stoichiometric mullite made of mechanically milled mixture of alumina and kaolin clay to investigate the effect of reinforcement content on the final properties of the prepared composites. The sintering processes were performed at 1400 °C under the initial and final applied pressures of 10 and 30 MPa and the vacuum condition of 17 Pa. The XRD patterns revealed the mullite and Si3N4 peaks as the dominant crystalline phases. Microstructural investigations demonstrated a uniform distribution of Si3N4 inside mullite matrix for the composites containing 5 and 10 wt% of the reinforcement particles. Meanwhile, some agglomerates of Si3N4 were observed in the microstructure of the mullite-15 wt%Si3N4 composite. Moreover, no evidence of reaction between the starting materials was detected through XRD and FESEM analyses. The highest values of hardness, bending strength, and fracture toughness obtained for the composite containing 15 wt% of Si3N4 were 19.14 GPa, 481 MPa and 3.85 MPa m−1/2, respectively. The fracture toughness mechanisms were detected as crack branching, breaking and deflection, as well as particles pulling-out, all of which were observed in the mullite-15 wt%Si3N4 composite.

Pore water salinity effect on the intrinsic compression behaviour of artificial soft soils

The framework of the intrinsic compression behaviour of normally consolidated soft clay proposed by Burland (1990) is widely adopted in engineering practices. However, further investigations should be conducted on its validity in the coastal and offshore environments to verify the effect of pore water salinity. In the present work, oedometer tests were performed on remoulded artificial soft clays (mixtures of kaolin and bentonite with 0%, 5%, 10%, and 20% of bentonite by mass). The artificial clays were salinized with sodium chloride solutions at concentrations 0 mol/L (distilled water), 0.17 mol/L, 0.51 mol/L, 0.86 mol/L, and 1.70 mol/L at water contents equal to 1.0–1.5 times of the liquid limits. The results showed that the ‘intrinsic’ properties of clays, including the compression index Cc⁎(100–1000 kPa), void ratio e100*, and compression line based on the void index Iv, changed with the pore water salinity. Following the empirical correlation proposed by previous researchers, the decrease in Cc⁎ caused by pore water salinity could be generally characterised by the liquid limit and void ratio at the liquid limit (eL). The dispersed correlation between the predicted e100⁎ and the experimental results in this study were caused by the significant changes in e0/eL controlled by pore water salinity. The relationships between void index Iv and vertical stress σv’ deviated from the intrinsic compression line (ICL) under the saline environment. For the artificial clay rich in smectite, the slopes of Iv–log σv’ before yielding increased with pore water salinity at the initial water content. Pore water salinity affected the intrinsic compression behaviour of soft clays primarily composed of kaolinite to a lesser extent.