Kaolin Resources Research Articles

Study on mechanism and kinetics of iron removal by chlorination roasting of coal gangue

Utilizing the abundant kaolin resources within coal gangue is economically beneficial, although the iron-containing phase in the minerals hampers the value of its utilization. In the present study, CaCl2 served as the chlorination agent for iron removal from coal gangue through chlorination roasting. The study revealed that when the roasting temperature is below 800 °C, CaCl2 decomposes into HCl and reacts with the iron content to form chloride, which then volatilizes. Comparatively, when the roasting temperature exceeds 800 °C, CaCl2 will decompose to produce HCl and Cl2 to accelerate the volatilization of iron. Through non-isothermal kinetic analysis, the apparent activation energy for iron removal by chlorination roasting of coal gangue was found to be 82.42 KJ/mol, and the pre-exponential factor was 6329.3 s−1. Correspondingly, isothermal kinetic analysis revealed the apparent activation energy of 84.2 KJ/mol and a pre-exponential factor of 6310.7 s−1. The optimal reaction kinetic mechanism function for iron removal through chlorination roasting of coal gangue was identified as the F3 chemical reaction order model via above kinetic analysis. The integral took the form g(α) = (1-α))2–1.

Hydrothermal and Metasomatic Kaolin Resource Estimation in the Quang Ninh area, Northeastern Vietnam

In northeastern Vietnam, hydrothermal‐metasomatic kaolinite-pyrophyllite from the secondary quartzite origin has been found in many places, including Pin Ho, Ban Ngai, Khe Khoai, Pec Sec Leng, Tan Mai ore occurrences, etc. They are exploited together with pyrophyllite, alunite, and high‐alumina quartzite as a byproduct. There were 810 chemical and mineral samples in the Quang Ninh area collected to investigate hydrothermal‐metasomatic kaolin resources. The ore minerals consist of kaolin-group minerals (kaolinite, dickite), pyrophyllite, quartz with minor sericite, alunite, diaspora, etc. They were identified by X-ray diffraction, and microscope and scanning electron microscope coupled with energy-dispersive X-ray spectroscopy analyses. Chemical analyses of major oxides were carried out on clays and parent rock samples by X-ray fluorescence spectrometry. The similarity-analogy in ore geology and mineral resource estimation based on statistical methods are employed to estimate hydrothermal‐metasomatic kaolin resources from the Quang Ninh area in northeastern Vietnam. The mineral resource estimation based on statistical methods shows 2.21 million tons of kaolin obtained by the content of aluminum oxide over 28% of the Pec Sec Leng mine, accounting for 14.3% in total. The similarity-analogy in ore geology indicates 158.16 million tons of kaolinite-pyrophyllite ores, of which, 22.0 million tons are kaolin. These methods display that the Quang Ninh area contains mainly pyrophyllite rather than kaolin resources. Our study suggests that the Quang Ninh area can be considered as a potential pyrophyllite resource in northeastern Vietnam for future exploration. Furthermore, the one resource estimation based on similarity-analogy in ore geology method shows an overview of the prospect on kaolinite-pyrophyllite resources in the Quang Ninh area, northeastern Vietnam.

Technoeconomic Study of Belitung Kaolin as Import Substitution Material in Fiber Cement Board Production

Cement board that commonly used as raw material for cheap housing component is calcium silicate cement board (fiber cement boards). However, the clay used as raw material for cement boards is still imported. In 2019, imported clay used for construction industry in Indonesia amounted to 57,000 tonnes per year with a transaction value of more than US $ 38 million. On the other hand, Indonesia, especially the province of Bangka Belitung, has a value of kaolin resources of 376,687,532 tons. Baristand Banjarbaru has successfully applied Belitung kaolin as a substitute for imported clay in cement board production. The physical properties of cement board made of kaolin Belitung were not significantly different from cement board made of imported clay.Therefore, Belitung kaolin has the potential to become a substitute for imported clay in cement board production and can be increased in terms of production scale so a techno-economic study is needed. Technoeconomic study had analyzed with the assumptions for a cement board production capacity of 100 tons / day, an investment age of 5 years, an initial investment of 0 for imported clay as raw material and 13,167,000,000 for kaolin as raw material or equivalent to 30% of sales. With the selling price of cement board Rp.55,000 / kg, the NPV of Belitung kaolin is 86,071,631,216.30 and the NPV of imported clay is 77,604,584,262.66. These results indicate that the cement board production business using Belitung kaolin as raw material is feasible to develop.

Development of antibacterial powder coatings using single and binary ion-exchanged zeolite A prepared from local kaolin

Antibacterial electrostatic powder paint coating with intended esthetic criteria was specially formulated for industrial applications using single (Ag+) and binary exchanged (Ag+ and Zn2+) zeolite A, which was prepared from local kaolin resources. Optimization studies on reaction parameters were conducted to obtain the most crystalline zeolite A from kaolin. The Ag+ and Zn2+ exchanged zeolite A samples prepared from kaolin were introduced as filler into the paint matrix during the electrostatic powder coating process. The antibacterial efficacy of the coatings was evaluated against E. coli and S. aureus based on Japanese Industrial Standard JIS Z 2801 method. Color analysis was also performed on these coatings in order to meet the least discoloration criteria, which is relevant to judge the quality of the coatings for industrial use. Single ion-exchanged coatings with Ag+ resulted in discoloring effect, which was diminished by adding Zn2+. The results indicated that the coatings containing both 2 wt% Ag+ and 12 wt% Zn2+ exchanged zeolite A exhibited 99.99% and 99.96% reduction for E. coli and S. aureus, respectively. This was of special interest for zeolite A samples that were prepared from local kaolin resources with more significant discoloration due to using natural kaolin as raw material. In conclusion, a low cost and antibacterial powder paint formulation with desired esthetic criteria using zeolites was achieved for the first time using a combination of Ag+ and Zn2+ ions.

Assessment of kaolin resources using electrical resisitivity method in part of Ekiti state southwest Nigeria

Consistent building of mineral database is very crucial to ascertaining the natural resources potential of a nation which may be valuable towards its development. Essentially, the study aimed at establishing the spatial extent and average thickness occurrence of the kaolin deposit in part of Ikere-ekiti, south western Nigeria using geophysical method. Seventy seven VES measurements and two parametric soundings were made. The data were processed and interpreted using IPIwin - a forward modelling software. The evaluated geoelectric parameers were used for the generation of maps(2D and 3D) depicting the mineral occurrence variation. Three-five subsurface layers were depicted within the study area with layer resistivity ranging from 1 to 7250 ohm-meters and layer thickness that range from 0.2 to 48 meters. Layers with a resistivity range of 1-150 ohm meters have been identified as the kaolin layers. Average thickness of the kaolin layer range from 0.8 to 46 meters. Overburden thickness were found to range from 0.3 to 44 meters.The lateral extents of the kaolin occurrence in the study site have been delineated by electrical geophysical sounding method. The obtained information may serve as database for detail exploration and exploitaion programme towards harnessing the reosurces.

Rare-metal granites as a potential source of critical metals: A geometallurgical case study

Because of their low grades in critical metals such as Light Rare Earth Elements (LREE) or Sn, rare-metal granites are not considered as economic for metal recovery but, when altered, they are often exploited for their industrial minerals. The St Austell rare-metal granite is well known for its world-class kaolin deposits which formed as a result of the extensive weathering and alteration of the underlying granite. The St Austell granite body is composed of several granite components, each having its own accessory minerals assemblage. As a result of the kaolinisation process, some metal-bearing accessory minerals of the granite, such as monazite (LREE) or cassiterite (Sn), are partially liberated from the gangue which allow their pre-concentration in the micaceous residue which is considered as a potential source for critical metals recovery. Similarities with other similar rare-metal granites suggest that topaz granite is the most prospective for disseminated magmatic Sn-Nb-Ta-REE mineralization. However, comparison of the potentiality of 3 granite types i.e., biotite, topaz and tourmaline granites suggest that biotite granites is actually the most prospective due to higher degree of kaolinisation of the biotite granite which favour pre-concentration of its accessory mineral in the micaceous residue. In order to develop a geometallurgical framework for extraction of kaolin and metals from the selected granite component, a field sampling campaign is performed. Core samples are processed in the laboratory using a characterisation program that mimics the full-scale kaolin refining route. Two main products are recovered through this program, viz. MR180 (−180 +53 µm) and P5 (−5 µm), which correspond to a fine micaceous residue and a fine kaolin product respectively. These products are both analysed routinely for major and minor trace elements by XRF and yields are recorded to indicate process performance. A selected number of MR180 samples are also being characterised in terms of particle size by laser light scattering, geochemistry by ICP-MS, and mineralogy by QEMSCAN®. Comparison of characterisation results of MR180 samples and corresponding industrial residue samples shows a good correlation, suggesting that sample analyses are representative for the in-situ deposit and the processing behaviour. Monazite is found to be either fully liberated or fully locked from one sample to the other. Next, pilot-scale gravity concentration tests are performed on micaceous residue samples. Characterisation of the processing products shows that monazite lost in the tailings is mostly locked within tourmaline or micas and is fine grained. Then, predictive regression models for spiral separation performance in terms of recovery, product grade and enrichment as a function of the feed grade are developed for MR180 LREE grade data. Finally, kaolin resources can be classified using quantitative indicators such as yield of the P5 product and the iron oxides content which provides insight into the kaolin quality in terms of whiteness. This geometallurgical classification can be used to delineate zones of interest within the deposit. Although kaolin quality and recovery primarily inform extraction planning, zones which are also of interest for metal recovery can be identified. The proposed model predicts whether the expected LREE grade and recovery satisfy the by-product requirements.

Challenges to access and safeguard mineral resources for society: A case study of kaolin in Portugal

Present and future demands of minerals require enlightened land use policies and practices that consider geological resources as a whole, anticipating potential conflicts and proposing/monitoring solutions to ensure the access to mineral resources and their responsible use. The use of a multi-criteria methodology able to balance the geological knowledge (grounding the identification of mineral resources) with the economic, environmental and social dimensions implicated in their current or foreseen exploitation may provide the way needed to conciliate the foremost goals of any mining planning and land-use planning exercises. The safeguarding of kaolin resources was the selected case study because: (i) the current and future access to these resources are confronted with different types of conflicts with other land uses; (ii) the exploitation and transformation of kaolin are increasingly important to the regional and national economy, generating as well numerous jobs all over the added value chain and attracting foreign investment; and (iii) the historical environmental liabilities related to old exploitations that still grounds strong apprehensions by the public in general. In this study, the Portuguese kaolin resources were represented by 136 specific tracts, 110 being classified as of “public importance” after considering criteria supporting the geological knowledge dimension. Preceded by a structured point densification scheme, an interpolation process was performed, within the kriging formalism. The resulting map delimited a total area of ≈342 km2 (0.4% of Portugal mainland) whose intrinsic value should support a safeguarding decision on the current and future access to kaolin resources in Portugal mainland. The 29 active and productive mines were further classified based on the economic, environmental and social dimensions and distributed within the three levels of priority for safeguarding, as proposed by the methodology. The results achieved are underestimated mostly due to several limitations of the available databases. Nevertheless, this remains a powerful potential tool to be applied for kaolin mineral resources safeguarding in two distinct and coexisting ways: (1) for future access, ensuring the supply of forthcoming generations and avoiding the sterilisation of tracts of “public importance”; and (2) for the short-medium term access, assigning specific areas to exploitation activities, regularly supplying the industry and markets. This methodology has been successfully applied to other minerals (e.g. Mateus et al., 2017), but additional efforts must be made to extend the assessment to other raw materials.

Composition, radioactivity, and possible applications of kaolin deposits of Sinai, Egypt

This work discusses the composition, radioactivity, and possible utilization of the kaolin resources in Sinai which are hosted in thick sandstone sequences belonging to the Carboniferous (Wadi Khaboba) and Early Cretaceous (Wadi Iseila and Abansakar) ages. The characterization of kaolin was done by microscopic and SEM examination, supported by XRD and ICP-MS analyses. The studied kaolin resources consist of kaolinite, as the main constituent, associated with subsidiary dickite and halloysite, and minor contribution of smectite and illite. The most dominant non-clay mineral is quartz, besides minor gypsum, dolomite, and hematite. Ferrugination dominates, in most cases, at the upper boundaries of the kaolin lenses, suggesting possible supergene activity. The high Al2O3/SiO2 ratio for the Cretaceous kaolin (0.54, in average) specifies its better grade relative to the Carboniferous kaolin (0.43, in average). The kaolin of the middle part of lens C in Wadi Iseila contains Si/Al molecular ratio of about unity, suggesting high-grade kaolin. The Carboniferous kaolin has enriched the radionuclides: U, Th, and Ra (at disequilibrium state due to leaching of eU relative to Ra) and the REE, relative to that of the Cretaceous age. The Carboniferous kaolin is characterized by a higher contribution of HREE (zircon signature), whereas LREE seems to be more influential for the Early Cretaceous kaolin (monazite signature). In spite of the very high CIA index (93 to 99), none of the analyzed kaolin deposits displays Ce abnormality. The high radioactivity of some Carboniferous kaolin can be a serious impediment for its utilization or its exportation. The kaolin of Sinai does not satisfy the international standards for paperwork industries and refractory manufacturing, but beneficiation may overcome this challenge. However, some lenses have high-grade kaolin with a low percentage of oxides of iron, magnesium, calcium, sodium, and potassium and a low radioactivity, hence nominated for the local refractory industry. The high-grade kaolin of Sinai fulfills the standards required for ceramics manufacturing in the global market. Grade 3 kaolin (< 30%, Al2O3) can be used in the manufacturing of white Portland cement and red glaze manufacturing on both local and global markets.

KARAKTERISTIK BAHAN BAKU KAOLIN UNTUK BAHAN PEMBUATAN BADAN ISOLATOR LISTRIK KERAMIK PORSELEN FUSE CUT OUT (FCO)

Kaolin is one of a very important raw material for fine porcelain ceramic production and the kaolin resources can be found in many places in Indonesia. Kaolin characteristic tests which include (chemical, physical, furnace, mineralogy, grain size) showed that the sample 1 and 2 do not meet the standard of porcelainceramic raw material. Fe2O3 concentrations of sample 1 and TiO2 concentrations of sample 2 were below SNI standard. In order to meet the SNI standard for isolator, post processing are required. These can further be important for the development of medium to high voltage isolator industries in Indonesia.

Kaolin and halloysite deposits of Brazil

AbstractBrazil is a significant producer of kaolin with almost 2.5 Mt in 2005 representing 10% of the world's total of 25.0 Mt. Brazil is now the second largest producer in the world, after the USA, having overtaken the United Kingdom in 2005. The kaolin resources are widespread throughout the country and are varied in their origin, physical and chemical properties and morphology. The kaolin industry in Brazil has shown a dramatic rise over the last 15 years with production of beneficiated kaolin increasing from 0.66 Mt in 1990 to 2.5 Mt in 2005. The reason for the growth is solely the development of large kaolin deposits in the Amazon Basin that account for 90% of Brazil's production. In 2005 there are just two companies involved in the production and sales of kaolin from the Amazon Basin, namely Imerys (RCC — Rio Capim Caulim) and Caemi (a subsidiary of CVRD — Companhia Vale do Rio Doce) with kaolin operations of CADAM (Jari River) and PPSA (Capim River operations).

Kaolin and halloysite deposits of China

China is a significant producer of kaolin with 2.1 Mt in 2002 representing 8.4% of the world's total of 24.9 Mt. The kaolin resources are widespread throughout the country and are varied in their origin, physical and chemical properties and morphology. The kaolin industry, compared to Europe and the USA, is fragmented with no single large company. In 2002, China was the world's largest producer of ceramics, particularly for sanitary ware and porcelain. Also, China is now the second largest producer of paper and paperboard in the world. The quality of kaolin and halloysite is suitable for ceramics with no need to import. However, the quality of existing paper/ board-coating clays is not up to the quality of imported material from Brazil and the USA and there is an urgent need to develop local resources to meet the present and future demands of the market.

Dreyer Conference on Global Kaolin Resources

Dreyer Conference on Global Kaolin Resources

FT-IR Partial Least-Squares Analysis of Tubular Halloysite in Kaolin Samples from the Mount Hope Kaolin Deposit

AbstractA method of infrared (IR) analysis for quantitative determination of tubular halloysite in mixtures with kaolinite was investigated for drill hole samples collected during an assessment of paper-coating kaolin resources at the Mount Hope Kaolin Deposit, Eyre Peninsula, South Australia. Tubular, dehydrated halloysite from the deposit does not readily intercalate formamide, and the proportion of tubes in &lt;2 μm size-fractions was determined initially from scanning electron micrographs. For samples showing a range of tube contents, a strong correlation between IR spectral response and counts of halloysite tubes was established using partial leastsquares analysis. This provided a rapid technique suitable for routine determination of tubular halloysite in samples from the Mount Hope deposit. Although the universality of the method remains to be tested, it offers an alternative approach to other analytical techniques for assessment of kaolin deposits where the presence of halloysite is suspected.

The application of DATAMINE in kaolin resource management

Abstract The computerized reserve evaluation system developed in house for ECCI’s UK kaolin operations served well from 1981 to 1987 but, with an evolving data base and increasingly more sophisticated demands placed upon it, its limitations became ever more apparent. It was clear that to maintain the system and develop it at the required pace was not feasible. Therefore the decision to replace it with a proprietary system was taken and DATAMINE was installed in July 1988. The new system has been installed to operate in parallel with the ECLIPSE ground modelling system which has been in operation at ECCI since early 1985 and has made significant impact in the fields of surveying, mapping and of quarry and tip design. At the present time, 900f the Mid Cornwall China Clay region has been mapped using this system and topographic update is readily available in digital format for quick assimilation into DATAMINE, speeding up model construction immeasurably. The application of DATAMINE is discussed in terms of its role as a tool in resource management and the construction of orebody models for primary kaolin deposits is briefly described. In order that the system could be made more specific to ECCI’s kaolin operations, a series of macros have been developed which essentially customize DATAMINE to ECCI’s specific requirement whilst maintaining total flexibility. These macros are described in broad outline and this serves to illustrate how the system is being applied in this particular situation. The ultimate goal is to provide a comprehensive and flexible overview of ECCI’s kaolin resources in SW England. This overview, coupled with a mineral extraction and debris disposal schedule, is a key component in the cost effective management of ECCI’s mineral business.

Kaolin: processing, properties and applications

Kaolins are white raw materials, their essential constituent being fine grained white clay, which are amenable for beneficiation that make them ideal for an assortment of industrial applications. Kaolin deposits can be classified into two types, primary (residual) and secondary (sedimentary). The main commercially important kaolin resources at the present time are the primary deposits of Cornwall in England and the sedimentary deposits in Georgia and South Carolina in the USA This review outlines the geology and occurrence of kaolins in the world and the state of the art in processing high-quality kaolins. The physical and chemical characteristics of kaolin are also reviewed with respect to their use for specific applications in paper, ceramics and refractories, plastics, rubber, adhesives and paint industries. The market outlook for world kaolin is outlined with respect to product specifications, markets and prices and the competition from other fillers such as calcium carbonate.

Kaolin Deposits of Weathering‐Residual in the Coastal Area of Guangdong Province

Abstract Kaolin deposits of weathering‐residual type make up a large proportion in different types of kaolin deposits and are widely used in ceramics, electron ceramics, rubber and paper industries. This paper discusses sys‐tematically this type of kaolin deposit with respect to their features of occurrence, mineralogical and chemical composition and transformation of minerais during supergene processes, thus providing some basic data for the rational exploitation and utilization of the kaolin resources.

Kaolins: their properties and uses

The main commercially important kaolin resources are the primary deposits in Cornwall and the sedimentary deposits in South Carolina and Georgia in the U.S.A. Annual world production is about 18 Mt (1 t = 10 3 kg). In 1981 the U.K. production was 2.6 x 10 6 t of which about 77 % represented paper filler and paper coating grades. About 15% of the U.K. production is used in ceramics. The kaolin extracted from the commercial deposits contains kaolinite as the major component together with ancilliary minerals. The kaolinite particles take the form of pseudo-hexagonal platelets with widths that vary from 10 to 0.1 pm and less. Surface chemical properties have been widely researched. There is no uniformity of view on the origin of the cation exchange capacity. Aqueous suspensions of kaolin are flocculated at low pH. This can be understood in terms of the positively charged edges and the negatively charged faces of the platelets. The deflocculation of kaolin under alkaline conditions is important, and is assisted by adding a polyanion. The Kubelka-Munk equations have provided a useful basis for interpreting the optical properties of kaolins in terms of an absorption coefficient ( k ) and a scattering coefficient ( s ). The parameter k ; is a bulk property and is interpreted in terms of light absorption by ancilliary minerals, by coatings of hydrated iron oxides on the kaolinite particles and by transition metals in the kaolinite structure. The parameter s depends on the size distribution of the platelets and the manner in which they are packed together. The rheological properties of deflocculated suspensions of kaolin in water are important in modern paper coating applications. The relation between the bulk physical properties of kaolin and rheology is complex. Viscosity at low rates of shear increases with increasing specific surface area of the kaolin. Viscosity at high rates of shear depends on the shapes of the particles and their packing. The extraction and production of kaolins are described for both primary and sedimentary deposits. The main use of kaolin is as a paper filler and a paper coating pigment. The various filler and coating grades are indicated, and effect of kaolin properties on coated sheet properties is discussed. Kaolin is a major component in most ceramic bodies. Examples of formulations are given. The manufacture of sanitaryware and tableware is discussed in terms of kaolin properties. Kaolin is used as an extender in aqueous based paints and as a filler in rubber and synthetic polymers.

Disability Evaluation Following Hand and Wrist Injuries

Because of their low grades in critical metals such as Light Rare Earth Elements (LREE) or Sn, rare-metal granites are not considered as economic for metal recovery but, when altered, they are often exploited for their industrial minerals. The St Austell rare-metal granite is well known for its world-class kaolin deposits which formed as a result of the extensive weathering and alteration of the underlying granite. The St Austell granite body is composed of several granite components, each having its own accessory minerals assemblage. As a result of the kaolinisation process, some metal-bearing accessory minerals of the granite, such as monazite (LREE) or cassiterite (Sn), are partially liberated from the gangue which allow their pre-concentration in the micaceous residue which is considered as a potential source for critical metals recovery. Similarities with other similar rare-metal granites suggest that topaz granite is the most prospective for disseminated magmatic Sn-Nb-Ta-REE mineralization. However, comparison of the potentiality of 3 granite types i.e., biotite, topaz and tourmaline granites suggest that biotite granites is actually the most prospective due to higher degree of kaolinisation of the biotite granite which favour pre-concentration of its accessory mineral in the micaceous residue. In order to develop a geometallurgical framework for extraction of kaolin and metals from the selected granite component, a field sampling campaign is performed. Core samples are processed in the laboratory using a characterisation program that mimics the full-scale kaolin refining route. Two main products are recovered through this program, viz. MR180 (−180 +53 µm) and P5 (−5 µm), which correspond to a fine micaceous residue and a fine kaolin product respectively. These products are both analysed routinely for major and minor trace elements by XRF and yields are recorded to indicate process performance. A selected number of MR180 samples are also being characterised in terms of particle size by laser light scattering, geochemistry by ICP-MS, and mineralogy by QEMSCAN®. Comparison of characterisation results of MR180 samples and corresponding industrial residue samples shows a good correlation, suggesting that sample analyses are representative for the in-situ deposit and the processing behaviour. Monazite is found to be either fully liberated or fully locked from one sample to the other. Next, pilot-scale gravity concentration tests are performed on micaceous residue samples. Characterisation of the processing products shows that monazite lost in the tailings is mostly locked within tourmaline or micas and is fine grained. Then, predictive regression models for spiral separation performance in terms of recovery, product grade and enrichment as a function of the feed grade are developed for MR180 LREE grade data. Finally, kaolin resources can be classified using quantitative indicators such as yield of the P5 product and the iron oxides content which provides insight into the kaolin quality in terms of whiteness. This geometallurgical classification can be used to delineate zones of interest within the deposit. Although kaolin quality and recovery primarily inform extraction planning, zones which are also of interest for metal recovery can be identified. The proposed model predicts whether the expected LREE grade and recovery satisfy the by-product requirements.