Kaolin Processing Research Articles

Characterization and processing of kaolin from southern Brazil for potential strategic application in the porcelain stoneware tiles manufacturing

The ceramic industry in the productive hub of Santa Catarina needs some raw materials with specific characteristics such as kaolin to manufacture its products. This clay mineral with a naturally variable chemical composition in relation to its geolocation (in extraction area composed by rock and combined with sediment materials), attributes significant increases in transport costs due to its distance from the main productive areas in southern Brazil. Thus, as a strategic alternative, the improvement of kaolin with a high quartz content (69.9%) from the northern region of the state of Santa Catarina (∼400 km from ceramic hub in the south of the state), more precisely from the municipality of Garuva, was sought. Unit processing operations by classifying this mineral for suitability for use in industry, resulted in an increase in the concentration of kaolinite. The results indicated that the proposed method reduced the amount of quartz and consequently increased the kaolinite content, resulting in an aluminum oxide content of approximately 28.20%, a value higher than the normal natural content of ∼19%.

SYNTHESIS OF ALUMINA FROM KAOLIN FOUND IN AJEBO, OGUN STATE, NIGERIA

This study proposes the utilization of kaolin as an alternate resource for alumina production due to the decreasing availability of bauxite ores in Nigeria. This project covers the procedures and operations required to produce a high surface area γ-alumina using kaolin, a refractory material. The kaolin used in this study was sourced from Ajebo in Ogun State, Nigeria. The mineral processing of kaolin was the initial step involving removing inherent impurities from the clay. Subsequently, calcination was performed to eliminate crystallised water and impurities and activate the kaolin's limited alumina content. This activation process facilitated the subsequent acid-leaching reactions. At 90oC, 5M HCl acid was used to leach meta-kaolin, which was then filtered. The filtrate was mixed with 5M NaOH at 900oC and was transformed into sodium aluminate. This reaction also facilitated the removal of magnesium and iron hydroxides. Subsequently, HCl was introduced to adjust the pH of the solution. The resulting aluminium hydroxide was then calcinated at temperatures of 700oC and 900oC for 2 hours each to produce γ-alumina. Ultimately, the calcined material was cooled to ambient temperature inside the furnace. The produced γ-alumina was further characterised using X-ray Fluorescence (XRF), Fourier Transform Infrared spectrometer (FTIR), and Scanning Electron Microscopy (SEM).

Evaluation of hydrocyclonage variables aiming at the optimization of the processing of kaolin of the primary type

Kaolin is a white rock, formed basically by the clay mineral kaolinite, for presenting favorable technological characteristics has a wide industrial application. Kaolin deposits are classified geologically into two types according to their origin: primary and secondary. Kaolin from the Seridó region of Paraíba and Rio Grande do Norte is of the primary type and its processing is carried out wet, generating two types of tailings. It is considered a difficulty in the current processing of this kaolin the method of mineral classification that is carried out by vibratory sieves. The main objective of this work was to evaluate the variables that influence the hydroclinage process for the classification of kaolin of the primary type. The trials were performed on a bench scale, using the Plackett-Burman factorial design. The best results were found in the T4 and T6 tests, which presented lower values of D50 and the results of XRF indicated that the aluminum oxide contents are higher in the overflow and the silica contents higher in the underflow. The trials indicated promising results for the classification of this type of kaolin, but a good adjustment of the operational variables is needed.

Sustainable conversion of Brazilian Amazon kaolin mining waste to zinc-based Linde Type A zeolites with antibacterial activity

Kaolin is a clay mineral with several applications, especially as filler in the paper industry. Brazil has the largest kaolin processing plant in the world located in the Amazon region. Kaolin mining activities generate high volumes of waste, resulting in additional costs and environmental impacts, and therefore, new approaches for their reduction are necessary. This work elucidates, for the first time, the technological valorization of abundant Amazon Brazilian kaolin mining waste to synthesize pure-phase zeolitic material with the antibacterial application. For the synthesis optimization, it was evaluated the influence of the type of kaolin (natural or thermally treated at 600 °C), the crystallization period (4, 6 and 24 h), the suppression of aluminum source (sodium aluminate) and the zinc ion-exchanging procedure. The materials were characterized by various techniques including powder X-ray diffraction (XRD), aluminum nuclear magnetic resonance with magic-angle spinning (27Al MAS NMR) and X-ray photoelectron spectroscopy (XPS), N2 adsorption/desorption isotherms, chemical analysis, thermogravimetric analysis (TGA), infrared spectroscopy (IR) and scanning electron microscopy (SEM). The results reveal that it is possible to direct the synthesis to the different zeolite structure with simple thermal treatment of the raw material, obtaining crystalline Linde Type A (LTA) or sodalite (SOD) zeolites using thermally treated or natural kaolin, respectively. Under the optimized synthesis conditions, the LTA zeolite was obtained after rapid crystallization in 6 h and without commercial aluminum supplementation. The Zn-exchanged LTA zeolites containing 4 and 7 wt% of Zn were applied as antibacterial materials. They presented growth inhibition zones between 7 and 8 mm for Gram-positive bacteria (Listeria monocytogenes and Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Salmonella enterica) while pure kaolin and LTA zeolite without Zn did not show antibacterial activity. These results offer new opportunities on the way that kaolin-mining industries manage their wastes.

From the micromorphology of paleoweathering fronts to paleoenvironmental analysis: A case study of the Cretaceous dune fields of Sanfranciscana Basin, Brazil

The work investigated the paleoenvironmental significance of kaolinite-rich weathering fronts developed during the Cretaceous in stabilized dune fields of Sanfranciscana Basin in Brazil. To this, was conducted a multi-scale analysis from the outcrops of paleosols to mineral grains and soil pores. The macro and micromorphology of paleoweathering fronts allow recognizing weathering features and estimating the porosity and hydraulic parameters (permeability, capillary pressure, and saturated hydraulic conductivity). Scanning electron microscope analyses were conducted to investigate surface microtextures of quartz grains for weathering process characterization based on dissolution microfeatures. Energy-dispersive X-ray spectrometry was utilized to identify chemical elements of clay minerals. The major and trace elements were analyzed using a Philips X-ray fluorescence (XRF) spectrometer (PW 2440). Our results showed that weathering fronts expand through preferential water paths (pipe and finger flow) in bedding planes in response to textural and porosity contrasts related to the bimodality (i.e., the difference of grain size distribution between overlapped sedimentary structures) of aeolian deposits. The dissolution features present in quartz grains, such as etching, pitting, total dissolution of grains, iron coatings, and booklets of well-developed kaolinite, reveal an increase in humidity and the pedogenetic kaolinization process typical of a humid tropical environment. These weathering patterns coincide with cooling events between the Albian and the Cenomanian report in the literature. Our study indicates that during the Cretaceous, the Sanfransicana Basin underwent climatic amelioration and a rise in water table level, which likely enhanced dune stabilization and the formation of an extensive geomorphic surface.

The use of red mud and kaolin waste in the production of a new building material: Pozzolanic pigment for colored concrete and mortar

The state of Para is one of the greatest producers of mineral substances in Brazil. Kaolin for paper coating industry and bauxite for alumina and aluminium production are amongst the most important commodities. The latter is responsible for the generation of red mud, a well-known residue from Bayer process. The kaolin processing plants are also responsible for the generation of large amounts of wastes, in this case, very fine-grained kaolinite (white mud). The research aimed to find a final destination for such residues by developing new building materials. The proposed material is a pozzolanic pigment produced through calcination and grinding of mixtures of red mud and kaolin waste. The pozzolanic pigments provided increased mechanical strength and color stability of the colored mortars relative to the inert pigment. The pozzolanic characteristics of the pigments reduced the leaching of the mortars. The new material has proven to be promising in its application as an innovative construction material, with the possibility of using these residues in a market that is little explored in Brazilian civil construction: colored mortars and concrete.

Dielectric Properties of Steatite Ceramics Produced from Talc and Kaolin Wastes

The main objective of this work was to study the use of kaolin processing wastes in the production of steatite ceramics, emphasizing mechanical strength and dielectric properties. Steatite ceramics were prepared using mixtures of talc with fine and coarse particle kaolin wastes (7.5, 10 and 12.5 wt.%) sintered at different temperatures (1200, 1250 and 1300°C). After sintering, the specimens were submitted to mineralogical and microstructural characterization. Linear shrinkage, apparent porosity, flexural strength and dielectric properties were also evaluated. Results showed the formation of the crystalline phases protoenstatite and quartz for all produced ceramics. The results verified for porosity, mechanical strength and dielectric properties proved to be suitable for the application of this material in electrical insulation.

Development of Eco-Friendly Mortars Produced with Kaolin Processing Waste: Durability Behavior Viewpoint

This study presents the development of new eco-friendly mortar compositions containing kaolin residues (KR) and assesses their durability behavior. Firstly, the natural and calcinated kaolin residues (600 °C, 650 °C, 700 °C, 750 °C, and 800 °C) were characterized by X-ray diffraction (XRD), differential thermal analysis (DTA), granulometric analysis, and surface area. The kaolin residue calcinated at 800 °C was chosen to be added to new compositions of mortar because it presented the best pozzolanic performance. The aging tests accomplished in internal (Ei) and external (Ee) environments were applied in mortars with a mass proportion of 1:2:6 (cement + KR: lime: sand), in which the KR, calcinated at 800 °C, replaced the cement in the mass fraction of 0%, 5%, 10%, 15%, 20%, and 30%. The Ei was performed for 30, 60, 90, 180, and 360 days, and the Ee for 90; 210; 360; and 512 days. After the aging tests were completed, the mortar compositions containing KR were evaluated to determine their mineralogical phases (XRD), compressive strength (CS), and thermal behavior (DTA and thermogravimetry). In summary, the KR addition to the mortar compositions decreases the mechanical resistance to compression; however, mortars with a substitution of 10% and 20% presented resistance values within the minimum limit of 2.4 MPa established by ASTM C 270.

Quadratic Mathematical Modeling of Sustainable Dry Beneficiation of Kaolin

Clay minerals are one of the most utilized minerals among non-metals. These are hydrous aluminum silicates with a layer (sheet-like) structure. Kaolin is a hydrous aluminosilicate mineral with a thin platelet structure. Kaolin is extensively used in paper, paint, and many other industries. Wet processing of kaolin will not be sustainable over the long term because global freshwater resources are becoming scarce. Hence, a process is necessary that does not consume water during the beneficiation of kaolin. This study developed a dry beneficiation process for low-grade kaolin of 59.6%, with 12% quartz and about 6% titaniferous impurities from Nagar Parkar, Sindh province, Pakistan. To develop a size difference between kaolinite and impurities, steel balls clad with rubber were used as the grinding media in a selective grinding unit. Screens of 60 and 400 mesh were employed to classify the feed of air classifier. Oversize +60 mesh was reground, 400 to 60 mesh fractions were sent to an air classifier, and −400 mesh was considered to be a product with the grade and recovery of 90.6% and 20.5%, respectively. Air classifier experiments were designed using central composite design. An experiment using a fan speed of 1200 revolutions per minute (rpm) and a shutter opening of 4.0 showed optimum results, with maximum kaolinite grade and recovery of 91.5% and 35.9%, respectively. The statistical models developed for grade and recovery predicted the optimum results at a fan speed of 1251 rpm and shutter opening of 3.3 with the maximum kaolinite grade and recovery of 91.1% and 24.7%, respectively. The differences between experimental and predicted grade and recovery were 0.1% and 2.4%, respectively. The characterization results showed the total upgrade of kaolin from 59.6% to 91.2%, with 27.1% recovery during the process. The designed methodology has the potential to improve the yield of the product by focusing on its recovery. Furthermore, the designed process can be improved by using different sized balls in the selective grinding unit. This beneficiation process can utilize more than one air classifier in series to achieve the targeted results.

Effects of grinding and dehydration on kaolin in a steam jet mill

AbstractSteam jet milling was applied for the first time to ultra-fine grind the filter cake (moisture content 23.80%) produced by a kaolin concentrator. The material was dehydrated and dried simultaneously during grinding, and the final ground sample met the moisture content requirement for powder products of <2%. The particle size of the ground kaolin samples decreased and the particle-size distribution was more concentrated, indicating that the steam jet milling was more effective for kaolin processing than the conventional dry grinding process. In addition, steam jet milling can improve the whiteness and decrease the crystal order of the samples, thus improving the kaolin properties in follow-up applications.

Mineração e desastres ambientais com rejeitos de bauxita e caulim no município de Barcarena-Pará-Brasil-Amazônia

O propósito deste trabalho é analisar os principais desastres ambientais ocorridos no município de Barcarena, estado do Pará, Amazônia Brasileira, ocorridos na atividade de beneficiamento de bauxita e caulim no período compreendido entre os anos de 2003 a 2018, causando degradação ambiental em corpos hídricos e nas comunidades próximas. A metodologia de pesquisa adotada para a elaboração deste artigo consistiu na revisão bibliográfica, legislação relativa à mineração e consulta a documentos oficiais de órgãos públicos como: inquéritos policiais, relatórios técnicos e laudos periciais. Foram analisados dados quantitativos e qualitativos sobre desastres ambientais registrados em nosso estado, causados pelo vazamento de rejeitos e efluentes líquidos derivados do beneficiamento desses minérios. Demonstrar-se-á, com os resultados deste estudo, que os recursos naturais, principalmente os hídricos, estão comprometidos pela mineração de bauxita e caulim, tornando-se necessária a execução de políticas públicas de gestão de riscos e desastres ambientais na Amazônia.

Estudo da potencialidade do concentrado de caulinita para aplicação cosmética

As máscaras argilosas são apontadas como as mais antigas preparações cosméticas utilizadas no tratamento de beleza em função da sua vasta gama de propriedades, logo, sua aplicabilidade na área cosmética depende primordialmente da composição química e mineralógica. Essa variabilidade na composição reforça a necessidade de se fazer estudos que proporcionam um maior entendimento dos compostos, bem como as diferentes possibilidades de aplicações. Objetivou-se caracterizar o concentrado de caulinita proveniente dos estados da Paraíba e do Rio Grande do Norte a fim de realizar um estudo comparativo com os parâmetros definidos por empresas do segmento. Para a realização da pesquisa foram coletadas de três diferentes unidades de beneficiamento de caulim, se-se ensaios laboratoriais seguindo metodologias específicas para o segmento cosmético e, posteriormente, comparações com especificações em laudos técnicos. Os ensaios foram: determinação de umidade, ensaio de peneiramento, determinação de pH, ensaio de absorção e ensaio colorimétrico qualitativo. Os resultados obtidos evidenciaram os valores de umidade para todas como em decorrência do processo de beneficiamento, enquanto nenhum ensaio de peneiramento não houve amostra com comportamento fora do limite estabelecido. Como forma de lucro levemente ácido com A2 e A3 valores satisfatórios, já no ensaio de absorção de oleosidade como A1 e A2 atenderam aos limites de variação.

ВЛИЯНИЕ ДАВЛЕНИЯ НА СТРУКТУРУ КАОЛИНИТА В ОГНЕУПОРНЫХ ГЛИНАХ НИЖНЕ-УВЕЛЬСКОГО МЕСТОРОЖДЕНИЯ ПО ДАННЫМ ИК-СПЕКТРОСКОПИИ

Актуальность исследования обусловлена необходимостью изучения структуры каолиновых глин в связи с их широким промышленным применением. Физические и физико-химические свойства глин изменяются при различных техногенных воздействиях на них, что обусловлено преобразованием кристаллической структуры. Цель: изучение влияния давления на структуру каолинита. Объект: каолиновая глина Нижне-Увельского месторождения Челябинской области. Метод: инфракрасная спектроскопия. Инфракрасные спектры регистрировались на ИК Фурье-спектрометре в интервале 400…3800 см–1. Обработка ИК-спектров проводилась с помощью программного обеспечения Fspec. Результаты экспериментальных исследований показали, что обогащенная каолиновая глина Нижне-Увельского месторождения Челябинской области, не подверженная воздействию давлением, характеризуется частично упорядоченной (дефектной) структурой. При воздействии давлений от 10 до 650 МПа глина характеризуется частично упорядоченной структурой, при давлениях от 700 до 800 МПа – слабо и неупорядоченной структурой. Обработка каолина давлением повышает дефектность структуры на уровне пакета. Связи между Al-OH, Si-O-Al, внутренними и внутриповерхностными гидроксилами разрушаются, что приводит к вытеснению Al из октаэдрического и Si из тетраэдрического листов и формированию «дырочных» энергетических центров в кристаллической решетке каолинита. При этом влияние давления до 150 МПа на формирование дефектов в каолините выше, чем при давлениях от 150 до 800 МПа. Кроме того, при обработке каолина давлением происходит образование дефектов структуры на межпакетном уровне за счет скольжения, вращения и прокатки структурных пакетов между собой

Geochemical and industrial properties of the Kejal kaolin deposit, NW Iran

The Kejal kaolin deposit, situated in the northwest of Iran, is considered a small part of the Hashtjin hydrothermal zone. The kaolinization process in this deposit has occurred in ignimbritic and volcanic tuff parent rocks in different grades such that severely kaolinized samples can be found in the middle section of the kaolinization profile. Kaolinite is the most abundant clay mineral in the studied samples. Quartz and cristobalite are the main minerals while anatase is the minor mineral of the kaolin samples. Among the major oxides, SiO2, Al2O3, and TiO2 show the highest concentrations in kaolin samples. The mass change calculations based on Ti show enrichment of Si, Al, Sr, and LREEs and depletion of alkali and alkali earth elements, HREEs, and HFSEs. The evaluation of REEs normalized to chondrite represents the higher concentration of LREEs comparing to HREEs. A remarkable positive Gd anomaly is seen in spider diagrams, which can be attributed to the primary CaO in the composition of ignimbritic precursor and also the Gd release due to the decomposition of Gd complexes and adsorption by clay minerals. The Eu negative anomaly is the other obvious characteristic of the studied samples and is most likely related to the alteration of feldspars, decomposition of plagioclase, and Eu liberation from the system. The significant positive correlations between REEs and Al2O3, TiO2, and P2O5 demonstrate the important role of clay minerals, REE-bearing phosphate minerals such as monazite, and titanium minerals like anatase and rutile in the kaolinization process and REE transport and establishment. The performed particle size test based on the hydrometer method shows about 20% of particles <2 μm and 36%-42% of particles <25 μm, which reveals a dominant medium particle size for these kaolin samples. Furthermore, the chemical composition of the analyzed samples represents around 20% alumina. Based on the obtained physicochemical evaluations, the Kejal kaolin deposit is medium- to low-grade kaolin, which is useable after simple processing in the paper industry as filler and in the ceramic industry as floor tiles.

QUANTIFICAÇÃO DE MULLITA PROVENIENTE DE RESÍDUOS DE CAULIM DA REGIÃO AMAZÔNICA: USO DO MÉTODO DE RIETVELD

QUANTIFICATION OF MULLITE FROM KAOLIN WASTES FROM THE AMAZON REGION: USE OF THE RIETVELD METHOD. Mullite is used to obtain a refractory material, there are several factors that influence the synthesis process of mullite: the preparation of the mixture, the precipitation and the reaction of SiO2 and Al2O3. For the synthesis of mullite, samples of kaolin processing residues were used as precursor material, because it presents SiO2 and Al2O3 in its composition. This work aimed to identify, by X-ray diffraction, and quantify the mineral phases present in samples of kaolin processing residues from the Amazon region calcined at 1300, 1400 and 1500 ºC, using the Rietveld method. The method allowed the refinement of the complex crystalline structures and was applied to the data supply for quantitative analyses with satisfactory results of good accuracy. The results of the quantification of crystalline and non-crystalline phases (with internal standard) in the samples calcined at 1500 ºC presented approximate values of mullite (62%), cristobalite (32%) and non-crystalline phases (6%), for both samples, indicating that the refinement model applied is optimal. These results obtained from the quantification of the phases by the method of Rietveld are presenting coherent and satisfactory values, in comparison with the theoretical ones by the phase diagram Al2O3 and SiO2

Sorption and desorption of radiocesium by muscovite separated from the Georgia kaolin

Radiocesium (137Cs) sorption by moderately weathered, sand-sized muscovite, obtained as a byproduct of kaolin ore processing, was observed at various concentrations of added stable Cs (0–100 μmol/L) over a 130 d period. After 18 h of batch sorption with 1 mmol/L NaCl as background electrolyte, conditional 137Cs Kd values were near 2000 L/kg across the entire range of added stable Cs. Over four succeeding months, the Kd values increased by large factors for suspensions with little added Cs but increased only slightly for the suspensions with the most added Cs. The large grains of muscovite used in this study behaved distinctly differently than previously studied, much finer illite in that highly Cs-selective but low-abundance cation exchange sites appeared to be unavailable to the aqueous Cs during the first few days of the experiment. Diffusion pathways to highly Cs-selective sites were thought to be much longer in the muscovite than in frayed edges of illite, causing the highly Cs-selective sites to be isolated from the bulk solution. The longer diffusion pathways may be due to much greater stiffness of the material bounding interlayer wedges in the muscovite than in illite. This isolation from solution led to slow uptake at trace levels of Cs though the final Kd values (after 130 d) at those levels were comparable to those found for some illite. After 130 days, the original solutions were replaced by new electrolyte solutions containing no Cs, to observe 137Cs desorption over another 130 d period. There was no indication of desorption of 137Cs from the slowly accessible, highly Cs-selective sites apparently reached by most of the 137Cs during sorption at the low Cs levels. The byproduct mica from kaolin processing might serve effectively as a chemically stable sorbent to isolate accidently released radiocesium and to hold it until the 137Cs is virtually gone.

Fungal bioextraction of iron from kaolin

Elevated iron content in low-grade kaolin is one of the chemical factors detrimental for its industrial applications. Therefore, various physical and chemical methods have been applied to decrease iron concentration in kaolin. One of the more feasible and environmentally friendly method is biobenefication via microbially-induced bioextraction. Therefore, this paper provides data on fungal bioextraction of iron from kaolin sample when incubated with fungal Aspergillus niger strain. After 19-day cultivation, approximately 45% of iron impurities have been bioextracted by fungus and distributed into fungal biomass or culture medium. The bioextraction was triggered by both acidification of culture medium by fungus (below pH of 1.5) and organic acids production, which are biologically conversed from glucose. However, bioextraction of silicon and aluminium, which form building blocks of clay minerals in kaolin, was reasonably low and did not overcome 0.15%. Thus, our data indicate that the bioextraction of iron using A. niger strain for kaolin processing is a viable alternative method for increasing quality of the low-grade kaolin.

Reaction mechanisms of calcined kaolin processing waste-based geopolymers in the presence of low alkali activator solution

The massive amount of kaolin processing waste was daily formed. To reduce the amount of their waste deposited in landfills and to increase the value- adding of recyclable waste, this work interested to use as raw materials in the preparation of geopolymer. This paper studied the reaction mechanisms of calcined kaolin processing waste-based geopolymers in the presence of low alkali activator solution by the pressing method. The reaction mechanisms of geopolymer were measured as a function of NaOH concentration by DSC, XRD, and FTIR analysis. Furthermore, the effects of NaOH concentration and curing time on the mechanical properties and microstructure of calcined kaolin processing waste-based geopolymer were investigated. The DSC, XRD, and FTIR results indicated that the geopolymerization reaction increased with higher NaOH concentrations. Forming the geopolymer by the pressing method led to the particles being close together in a compact matrix. Subsequently, their surfaces were dissolved with NaOH solution, inducing the geopolymerization reaction. This reaction and continuous reaction resulted in the compressive strength and microstructure of the geopolymer. The compressive strengths of the geopolymer synthesized with NaOH concentration of 10 M (curing time of 7 days) and a curing time of 28 days were 26.98 MPa and 28.55 MPa, respectively, which were approximately 22.58% and 52.35% higher compared to the geopolymer synthesized with NaOH concentration of 4 M and a curing time of 1 day. The SEM micrographs of the geopolymer samples displayed more geopolymeric gel and denser matrices with increases in NaOH concentration and curing time. The nitrogen adsorption and pore volume decreased with increases in NaOH concentration and curing time. Synthesis of geopolymers using kaolin processing waste as a raw material is a value- adding and environmentally friendly process.

Study of the Thermal Stability of Faujasite Zeolite Synthesized from Kaolin Waste from the Amazon

The waste from the processing of kaolin in the Amazonian region of Brazil was subjected to a calcination process at 700°C for 2 h to obtain metakaolin, which, together with sodium hydroxide and sodium silicate, formed the reaction mixture. This mixture was subjected to an aging step (24 h at 60 rpm), and a subsequent hydrothermal process at 110°C for 10 h. By means of X-ray diffraction (XRD), differential thermal and thermogravimetric analysis (DTA/TG) and scanning electron microscopy (SEM) techniques, the crystallization of a single phase, faujasite (FAU) zeolite, was observed. In the postsynthesis process, it was verified by means of XRD that the thermal stability of this structure persists up to a temperature of 600°C. At 800°C, the structure of FAU collapses. Beginning at 850°C, new nepheline phases are formed, and at 1000°C, nepheline and mullite phases are formed.

Characterization of Kaolin Residues from the Jarí Valley Reservations Provided by Cadam S/A Company

The ceramic industry is one of the most important productive chains of the State of Pará, generating both money and employment. Kaolin has many industrial applications and new uses are constantly surveyed. Although the extraction and processing of kaolin contribute to the economy growth, the activity also provokes serious environmental issues. Being aware of the environmental problem caused by the inadequate decomposition of kaolin residues from the beneficiation process of these minerals, which pollute and attack the environment, this paper aims the chemical, physical and mineralogical characterization of the kaolin residue from the post-treatment disposal provided by CADAM S/A company. The main oxides in the residues were SiO2and Al2O3. In the X-ray diffraction analysis it was verified that the kaolin residue is basically formed by kaolinite and quartz, in the particle size analysis it was observed that the medium size of the particle was of 1,77 μm.