In kraft pulp mills, lime is used to convert sodium carbonate to sodium hydroxide (Ca(OH)2). The causticizing reaction precipitates lime mud which is washed, dewatered, and calcined in a lime kiln to generate lime for reuse. Clean, dry, and more stable lime mud helps reducing the energy usage of the kiln, improving burner flame stability, minimizing ring formation, and alleviating emissions of reduced sulphur gases from the kiln stack. The dewatering efficiency of lime mud is greatly affected by the mud and liquor properties, and the equipment design and operation. The properties of the mud vary continuously due to changes in the liquor strength, lime quality and dosage, which is known as the “liming ratio”. Many studies have been carried out to relate lime mud properties to dewatering and filtration behaviours, the mechanisms by which lime mud becomes difficult to settle and filter are not well understood. A systematic study was therefore conducted to examine the effect of the liming ratio on the settling rate and filterability of lime mud. The results show that the mud settling rate and filterability decreased with an increase in liming ratio. The effect was more noticeable as the liming ratio exceeded a critical level leading to an overliming condition. The results also show that the particle size of the resulting lime mud did not appreciably change with liming ratio. Therefore, the decrease in settling rate and filterability cannot be attributed to the smaller particle size of Ca(OH)2 compared to that of lime mud as commonly believed. Rather, it was caused by a change in zeta potential of Ca(OH)2-containing mud particles.This study also shows that the zeta potential of the mud slurry increases proportionally to the free lime content in the lime mud. This suggests that the zeta potential can be used to indicate the extent of overliming in the causticizing plant. The correlation between zeta potential and free lime content can be used to develop an on-line overliming monitoring system to help regulate theamount of lime addition to the system to achieve optimum operating conditions for the mud settling and filtering equipment.

In kraft pulp mills, lime is used to convert sodium carbonate to sodium hydroxide (Ca(OH)2). The causticizing reaction precipitates lime mud which is washed, dewatered, and calcined in a lime kiln to generate lime for reuse. Clean, dry, and more stable lime mud helps reducing the energy usage of the kiln, improving burner flame stability, minimizing ring formation, and alleviating emissions of reduced sulphur gases from the kiln stack. The dewatering efficiency of lime mud is greatly affected by the mud and liquor properties, and the equipment design and operation. The properties of the mud vary continuously due to changes in the liquor strength, lime quality and dosage, which is known as the “liming ratio”. Many studies have been carried out to relate lime mud properties to dewatering and filtration behaviours, the mechanisms by which lime mud becomes difficult to settle and filter are not well understood. A systematic study was therefore conducted to examine the effect of the liming ratio on the settling rate and filterability of lime mud. The results show that the mud settling rate and filterability decreased with an increase in liming ratio. The effect was more noticeable as the liming ratio exceeded a critical level leading to an overliming condition. The results also show that the particle size of the resulting lime mud did not appreciably change with liming ratio. Therefore, the decrease in settling rate and filterability cannot be attributed to the smaller particle size of Ca(OH)2 compared to that of lime mud as commonly believed. Rather, it was caused by a change in zeta potential of Ca(OH)2-containing mud particles.This study also shows that the zeta potential of the mud slurry increases proportionally to the free lime content in the lime mud. This suggests that the zeta potential can be used to indicate the extent of overliming in the causticizing plant. The correlation between zeta potential and free lime content can be used to develop an on-line overliming monitoring system to help regulate theamount of lime addition to the system to achieve optimum operating conditions for the mud settling and filtering equipment.

The pulp and paper industry has been struggling to meet the new and stringent TRS (Total Reduced Sulphur) emission compliance standards established in recent years. However, a new approach by some regulatory bodies gives intricate operational parameters a new and important role in achieving environmental compliance. TRS compounds that cause the distinctive pulp mill odour, originate from sodium sulphide in white liquor used in the kraft pulping process. Up to 20% of TRS emissions could originate from the lime kiln and lime mud solids content is one of the operational parameters that could help reduce the TRS emissions from the lime kiln. Residual sodium sulphide in the lime mud that results in TRS gases, is dissolved in the moisture content of the mud. Although efficient lime mud washing can remove most of the residual sodium sulphide, the remaining moisture content of the mud still contains some sodium sulphide. Therefore, improved lime mud dewatering can be effective in reducing the TRS emissions from the lime kiln. Data presented in this study confirms that as the lime mud solids content increases, TRS emissions from the lime kiln decrease. Data analysis demonstrates a negative linear correlation at 5% significance level between TRS emissions and lime mud solids.

The pulp and paper industry has been struggling to meet the new and stringent TRS (Total Reduced Sulphur) emission compliance standards established in recent years. However, a new approach by some regulatory bodies gives intricate operational parameters a new and important role in achieving environmental compliance. TRS compounds that cause the distinctive pulp mill odour, originate from sodium sulphide in white liquor used in the kraft pulping process. Up to 20% of TRS emissions could originate from the lime kiln and lime mud solids content is one of the operational parameters that could help reduce the TRS emissions from the lime kiln. Residual sodium sulphide in the lime mud that results in TRS gases, is dissolved in the moisture content of the mud. Although efficient lime mud washing can remove most of the residual sodium sulphide, the remaining moisture content of the mud still contains some sodium sulphide. Therefore, improved lime mud dewatering can be effective in reducing the TRS emissions from the lime kiln. Data presented in this study confirms that as the lime mud solids content increases, TRS emissions from the lime kiln decrease. Data analysis demonstrates a negative linear correlation at 5% significance level between TRS emissions and lime mud solids.

Made available in DSpace on 2015-03-26T13:53:14Z (GMT). No. of bitstreams: 1 texto completo.pdf: 1249243 bytes, checksum: 8c6f9a1bc107ee1e64c128445080824f (MD5) Previous issue date: 2010-02-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Supplementation of Ca in eucalyptus plantations have been necessitated by the poverty of this nutrient in most soils for reforestation and the high demand for Ca by culture. Wastes from pulp industry have potential for use as sources of Ca, but need to have their behavior in soil and crop response to your application further studies. The objectives of this study were to evaluate the effects of applying a mixture of industrial waste cellulose (CCM 40:4, composed of biomass ash, dregs, grits and lime mud) on some soil chemical properties and as a source of Ca for eucalyptus and its effect on the growth of this species. A experiment was installed in Eunapolis-BA in a randomized block with nine treatments derived from a factorial combination of two sources of Ca (lime and CCM 40:4) and four doses of Ca (0, 5, 1, 2 and 3 times the need for supplemental Ca estimated by Nutricalc for a yield of 60 m3 ha-1 yr-1), plus a treatment without the application of the sources of Ca. The sources were applied in total area, without incorporation. Soil samples were collected at layers 0-10, 10-20 and 20- 40 cm depth for chemical analysis at 120 days after treatment. Around this time, samples of leaves for analysis of macro and micronutrients. One year after planting, the diameter at breast height and height were measured and stem volume with bark estimated. In soil samples were analyzed for pH, Ca2+, Mg2+, Al3+ and Na+, and the levels of available K, P, Cu, Mn, Fe, Zn, Cr, Cd, Ni and Pb .Was performed analysis of variance each collection depth and the dose effects were assessed by regression analysis. The pH and Al3+, Ca2+ Mg2+ soil in three layers examined were influenced by the application of CCM 40:4 mixture, reducing in Al3+ and increase other elements analyzed. The implementation of CCM 40:4 mixture caused increased availability of P in the surface layer and cubically influenced the availability of K in the deeper layers. There was no influence of application of the sources in the levels of Na, Mn and Zn in any of the studied layers. However, sources have reduced levels of Fe available, 120 days after application. There was a quadratic response to both Cu through the application of doses of Ca as CCM 40:4. The available contents of Cr, Cd, Ni and Pb extracted by DTPA-TAE were below the detection limit of the device used. There was no influence of the doses of both sources in foliar Ca, Mg, P and Zn by four months of age, however, these levels were within the normal range for growing eucalyptus. For K linearly increased when using CCM 40:4, with no change in its nutrient content when using lime. For Fe there was a reduction in its content depending on the dose. There was no influence of the doses from both sources in plant height and volume with bark. We conclude that the mixing of wastes from pulp industry can be used as liming and as a source of Ca, the application of mixing did not increase the concentration of heavy metals available and increased small amount of Na+, and that the Ca natural soil along with the phosphate rock applied on the initial demand met by Ca eucalyptus. / A suplementação de Ca em cultivos de eucalipto tem sido necessária em virtude da pobreza desse nutriente na maioria dos solos destinados ao reflorestamento e da elevada demanda de Ca pela cultura. Resíduos da indústria de celulose apresentam potencial para uso como fontes de Ca, porém precisam ter seu comportamento no solo e a resposta das culturas à sua aplicação mais bem estudados. Os objetivos desse trabalho foram avaliar os efeitos da aplicação de uma mistura de resíduos da indústria de celulose (CCM 40:4, composta de cinza de biomassa, dregs, grits e lama de cal) sobre alguns atributos químicos do solo e como fonte de Ca para o eucalipto, e seu efeito no crescimento inicial desta espécie. Um experimento de campo foi instalado, em Eunapólis-BA, em delineamento de blocos casualizados, com nove tratamentos, resultantes da combinação fatorial entre duas fontes de Ca (calcário dolomítico comercial e mistura CCM 40:4) e quatro doses de Ca (0,5; 1; 2 e 3 vezes a necessidade de suplementação de Ca estimada pelo Nutricalc para uma produtividade de 60 m3 ha-1 ano-1), além de um tratamento sem aplicação das fontes de Ca. As fontes foram aplicadas em área total, sem incorporação. Foram coletadas amostras de solo, nas camadas 0-10, 10-20 e 20-40 cm de profundidade para análise química aos 120 dias após aplicação dos tratamentos. Nessa mesma época foram coletadas amostras de folhas para análise de macro e micronutrientes. Um ano após o plantio, foram mensurados o diâmetro à altura do peito e a altura e o volume de tronco com casca estimado. Nas amostras de solos foram determinados o pH em água, Ca2+, Mg2+, Al3+ e Na+, e os teores disponíveis de K, P,Cu, Mn, Fe e Zn, Cr, Cd, Ni e Pb. Foi realizada análise de variância para cada profundidade de coleta, e os efeitos de doses foram avaliados por meio de análise de regressão. O pH e os teores de Al3+, Ca2+ e Mg2+ do solo, nas três camadas analisadas, foram influenciados pela aplicação da mistura CCM 40:4, com redução do Al3+ e aumento dos demais elementos analisados. A aplicação da mistura CCM 40:4 causou aumento da disponibilidade de P na camada superficial e influenciou de forma cúbica a disponibilidade de K nas camadas mais profundas. Não houve influência da aplicação das fontes nos teores de Na+, Mn e Zn em nenhuma das camadasestudadas. Porém, as fontes reduziram os teores de Fe disponível, 120 dias após sua aplicação. Houve resposta quadrática para os teores de Cu em virtude da aplicação das doses de Ca na forma de CCM 40:4. Os teores disponíveis de Cr, Cd, Ni e Pb extraídos pelo DTPA-TAE ficaram abaixo do limite de detecção do aparelho empregado. Não houve influência das doses de ambas as fontes no teor foliar de Ca, Mg, P e Zn aos quatro meses de idade, porém, esses teores encontram-se dentro da faixa de normalidade para a cultura do eucalipto. Para K houve aumento linear quando se utilizou a CCM 40:4, sem que houvesse alteração no teor deste nutriente quando se utilizou calcário. Para Fe houve redução no seu teor em função das doses. Não houve influência das doses de ambas as fontes na altura das plantas e no volume com casca. Conclui-se que a mistura de resíduos da indústria de celulose pode ser usada como corretivo da acidez e como fonte de Ca; a aplicação da mistura de resíduos não elevou os teores disponíveis de metais pesados e incrementou pequena quantidade de Na trocável; e que o Ca natural do solo juntamente com o aplicado via fosfato natural reativo atenderam a demanda inicial por Ca do eucalipto.

O resíduo sólido estudado na presente pesquisa e decorrente da associação de lama de calcário e dregs (expressão muito utilizada na indústria do papel, inclusive no Brasil, que poderia ser traduzida como \'borra\'), materiais gerados na fabricação de papel. Tradicionalmente, este resíduo é depositado em aterros sanitários ou em áreas controladas. No entanto, a disponibilidade de espaços adequados para a disposição é pequena, e a conservação dos mesmos é muito dispendiosa, visto que apresentam riscos de contaminação para o ambiente e fauna circundantes. Assim, este tipo de solução não é mais visto como viável a longo prazo. Este trabalho tem como objetivo principal determinar, a partir de ensaios de laboratório, o comportamento mecânico de misturas constituídas com solos e o resíduo em destaque, visando a sua utilização na construção rodoviária. Foram compactados corpos-de-prova com e sem adição de resíduo na energia normal do Proctor, variando-se o tipo de solo, o teor de cal e o tempo de cura, e posteriormente foram submetidos a ensaios de compressão simples, compressão diametral e índice de suporte Califórnia. Complementarmente, foram realizados ensaios de difração de raios-X e microscopia eletrônica por varredura para determinar, respectivamente, a composição química e micro-estrutura do resíduo. Os resultados mostraram que a adição do resíduo da fabricação de papel aos solos não melhora as propriedades mecânicas das misturas compactadas, sendo necessária a utilização de um estabilizante, como a cal, para melhorar as más características. Porém para os solos estudados, as misturas de solo, resíduo e cal apresentaram melhor comportamento mecânico que as misturas de solo-cal, oferecendo uma solução factível para a utilização deste resíduo na construção rodoviária. / The solid waste studied in the present research results from the association of lime mud and dregs, these materials are generated during the paper manufacturing. Traditionally, this waste is disposed of either surface impoundment or landfills. However, there is limited appropriate land availability for these disposal practices, and its maintenance is costly, due to the present contamination risks for the surrounding environment and fauna. Therefore, this kind of solution is no longer seen as long term viable. This work has the main objective of studying, based on laboratory tests, the mechanical behavior of soils and the wastes in focus mixtures, seeking their utilization in road construction. Specimens with and without the addition of waste were compacted at the normal proctor energy, varying the soil type, the lime rate and curing time, afterwards they were submitted to tests of unconfined compressive strength, indirect tensile strength and California bearing ratio. Complementary, tests of ray-X diffraction and spectrum electronic microscopy were executed to respectively determine the chemical composition and microstructure of the waste. The results showed that the addition of paper mill wastes to soils does not improve the mechanical properties of the compacted mixtures, being necessary the use of a stabilizer, such as lime, to improve its poor characteristics. However for the studied soils; the lime stabilized soils and the waste mixtures presented bettermechanical behavior than the lime stabilized soils offering a feasible solution for the use of this waste in road construction.

Made available in DSpace on 2017-07-21T20:42:41Z (GMT). No. of bitstreams: 1 Edney Melo Neves.pdf: 2401483 bytes, checksum: 62f3e20bc1f9efd71b600800871b29fc (MD5) Previous issue date: 2013-08-28 / This work aims to investigate the incorporation of waste lime mud, generated by the pulp industry, in the formulations of the porous ceramic body in substitution the raw material calcite. The experiments covered the physico-chemical and mineralogical of the raw materials, the waste, and the compositions proposals. It was verified that the residue has the carbonate content slightly larger than the calcite, a larger average particle size and similar thermal properties. The ceramic bodies studied were prepared by the wet process, conformed by uniaxial pressing and sintered in an industrial furnace at 1135 °C and laboratory at temperatures of 1115 °C, 1125 °C, 1135 °C and 1145.°C with sintering cycle fast. Then, technological tests were carried total shrinkage, absorption of water, loss on ignition, mechanical strength and colorimetric coordinate. It was observed that, with the increase in substitution of calcite for the residue lime mud, the total shrinkage test samples decreased, while increasing the dimensional stability. Thus, other formulations have been proposed with the objective of keeping the shrinkage closest to standard composition. Compositions were selected, tested and characterized by differential thermal analysis and thermogravimetryc analysis, dilatometry and microstructure analysis of the fracture of the sintered specimens. The results shown to be possible to use waste "lime mud" in wall tiles compositions as a substitute for raw material calcite, keeping requirements of the NBR 13818, and with the advantage of reducing the percentage of carbonates in the composition, increased dimensional stability during sintering, lighten the color of ceramic body, addition to being an environmental solution. / Este trabalho tem por objetivo investigar a incorporação do resíduo “lama de cal”, gerado pela indústria de celulose, nas formulações de massa cerâmica de revestimento poroso em substituição a matéria-prima calcita tradicional. Os experimentos abrangeram a caracterização físico-química e mineralógica das matérias-primas, do resíduo e das composições propostas. Verificou-se que o resíduo possui o teor de carbonatos ligeiramente maior que a calcita tradicional, um maior tamanho médio de partículas, e propriedades térmicas semelhantes. As massas cerâmicas estudadas foram preparadas pelo processo via úmida, conformada por prensagem uniaxial e sinterizadas em forno industrial a 1135 °C e de laboratório nas temperaturas de 1115.°C, 1125 °C, 1135 °C e 1145 °C em ciclo de sinterização rápido. Em seguida, foram realizados os ensaios tecnológicos de retração total, de absorção de água, de perda ao fogo, de resistência mecânica e de coordenada colorimétrica. Constatou-se que, conforme o aumento da substituição da calcita tradicional pelo resíduo “lama de cal”, a retração total dos corpos de provas diminuiu, além de aumentar a estabilidade dimensional. Assim, foram propostas outras formulações com o objetivo de manter a retração próxima a composição padrão. Selecionaram-se composições e realizaram-se os ensaios de análise térmica diferencial e termogravimétrica, dilatometria, e análise da microestrutura da fratura dos corpos de prova sinterizados. Os resultados revelaram ser possível o uso do resíduo “lama de cal” em composições de monoporosa como substituto da matéria-prima calcita tradicional, mantendo os requisitos exigidos pela NBR 13818, e com as vantagens de redução do percentual de carbonatos na composição, aumento da estabilidade dimensional durante a sinterização, clarear a cor da massa, além de ser uma solução ambiental.

O resíduo sólido estudado na presente pesquisa e decorrente da associação de lama de calcário e dregs (expressão muito utilizada na indústria do papel, inclusive no Brasil, que poderia ser traduzida como \'borra\'), materiais gerados na fabricação de papel. Tradicionalmente, este resíduo é depositado em aterros sanitários ou em áreas controladas. No entanto, a disponibilidade de espaços adequados para a disposição é pequena, e a conservação dos mesmos é muito dispendiosa, visto que apresentam riscos de contaminação para o ambiente e fauna circundantes. Assim, este tipo de solução não é mais visto como viável a longo prazo. Este trabalho tem como objetivo principal determinar, a partir de ensaios de laboratório, o comportamento mecânico de misturas constituídas com solos e o resíduo em destaque, visando a sua utilização na construção rodoviária. Foram compactados corpos-de-prova com e sem adição de resíduo na energia normal do Proctor, variando-se o tipo de solo, o teor de cal e o tempo de cura, e posteriormente foram submetidos a ensaios de compressão simples, compressão diametral e índice de suporte Califórnia. Complementarmente, foram realizados ensaios de difração de raios-X e microscopia eletrônica por varredura para determinar, respectivamente, a composição química e micro-estrutura do resíduo. Os resultados mostraram que a adição do resíduo da fabricação de papel aos solos não melhora as propriedades mecânicas das misturas compactadas, sendo necessária a utilização de um estabilizante, como a cal, para melhorar as más características. Porém para os solos estudados, as misturas de solo, resíduo e cal apresentaram melhor comportamento mecânico que as misturas de solo-cal, oferecendo uma solução factível para a utilização deste resíduo na construção rodoviária. / The solid waste studied in the present research results from the association of lime mud and dregs, these materials are generated during the paper manufacturing. Traditionally, this waste is disposed of either surface impoundment or landfills. However, there is limited appropriate land availability for these disposal practices, and its maintenance is costly, due to the present contamination risks for the surrounding environment and fauna. Therefore, this kind of solution is no longer seen as long term viable. This work has the main objective of studying, based on laboratory tests, the mechanical behavior of soils and the wastes in focus mixtures, seeking their utilization in road construction. Specimens with and without the addition of waste were compacted at the normal proctor energy, varying the soil type, the lime rate and curing time, afterwards they were submitted to tests of unconfined compressive strength, indirect tensile strength and California bearing ratio. Complementary, tests of ray-X diffraction and spectrum electronic microscopy were executed to respectively determine the chemical composition and microstructure of the waste. The results showed that the addition of paper mill wastes to soils does not improve the mechanical properties of the compacted mixtures, being necessary the use of a stabilizer, such as lime, to improve its poor characteristics. However for the studied soils; the lime stabilized soils and the waste mixtures presented bettermechanical behavior than the lime stabilized soils offering a feasible solution for the use of this waste in road construction.