370 Revista Internacional de Contaminación Ambiental Rev. Int. Contam. Ambient 0188-4999 Universidad Nacional Autónoma de México México claudio.amescua@atmosfera.unam.mx 37060163020 https://doi.org/10.20937/RICA.2019.35.01.17 Sin sección CHARACTERIZATION OF PULP AND PAPER MILL WASTE FOR THE PRODUCTION OF WASTE-BASED CEMENT CARACTERIACIÓN DE RESIDUOS DE PAPEL Y CELULOSA PARA LA PRODUCCIÓN DE CEMENTO CON BASE EN DESECHOS Simão Lisandro lisandrosimao@gmail.com Hotza Dachamir Raupp-Pereira Fabiano Labrincha João A. Montedo Oscar R.K. Graduate Program in Materials Science and Engineering (PGMAT), Department of Mechanical Engineering (EMC), Federal University of Santa Catarina (UFSC), PO Box 476, 88040-900 Florianópolis (SC), Brazil Graduate Program in Materials Science and Engineering (PGMAT), Department of Mechanical Engineering (EMC), Federal University of Santa Catarina (UFSC) Brasil Graduate Program in Chemical Engineering (POSENQ), Department of Chemical Engineering (EQA), Federal University of Santa Catarina (UFSC), PO Box 476, 88040-900 Florianópolis (SC), Brazil Graduate Program in Chemical Engineering (POSENQ), Department of Chemical Engineering (EQA), Federal University of Santa Catarina (UFSC) Brasil Graduate Program in Materials Science and Engineering (PGMAT), Department of Mechanical Engineering (EMC), Federal University of Santa Catarina (UFSC), PO Box 476, 88040-900 Florianópolis (SC), Brazil Graduate Program in Chemical Engineering (POSENQ), Department of Chemical Engineering (EQA), Federal University of Santa Catarina (UFSC) Brasil Department of Materials and Ceramic Engineering / CICECO- Aveiro Institute of Materials, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal Department of Materials and Ceramic Engineering / CICECO- Aveiro Institute of Materials, University of Aveiro Portugal Graduate Program in Materials Science and Engineering (PPGCEM), University of Southernmost Santa Catarina (UNESC), Brazil Graduate Program in Materials Science and Engineering (PPGCEM), University of Southernmost Santa Catarina (UNESC) Brasil lisandrosimao@gmail.com Febrero-Abril 2019 35 1 237 246 01 07 2017 01 04 2018 Abstract

Waste generation is increasing in many industries. Therefore, effective measures are required to secure an environmentally sustainable and economically viable waste destination. Co-processing in clinker kilns at high temperatures and incorporation into cement matrices may stabilize many types of industrial waste. This paper presents the results of a study that characterized pulp and paper mill waste and their recycling in clinker production. Chemical characterization and estimation of the hazardous potential of lime mud, biomass ash, and wastewater treatment plant (WWTP) sludge were performed in accordance with brazilian standard (NBR) 10004:2004. Biomass ash and WWTP sludge were classified as non-hazardous (class II), while lime mud was classified as hazardous (pH > 12.5, class I). These wastes were mixed (69 wt % lime mud, 29 wt % biomass ash, and 2 wt % WWTP sludge), and the resulting mixture was processed at 1455 ºC to generate ‘Ecoclinker’. The clinker was characterized, milled, and mixed with calcium sulphate for use as an ‘Ecocement’. Mortars were obtained and cured for periods of seven and twenty-eight days. The hardened product exhibited a mechanical strength of ~20 MPa. The leaching and pH tests indicated that these parameters were within the permitted limits, confirming that this waste-based cement was non-hazardous.

 Resumen

La generación de residuos sólidos está aumentando en muchos sectores industriales; por lo tanto, se requieren medidas efectivas para garantizar un descarte de residuos que sea ambientalmente adecuado y económicamente viable. El coprocesamiento en hornos de producción de clínker a altas temperaturas, así como la incorporación en matrices de cemento, son estrategias utilizadas para estabilizar muchos tipos de residuos industriales. En este estudio se analizan los resultados de un estudio acerca de la caracterización de residuos de papel y celulosa y su reciclaje en la producción de clínker. La caracterización química y la estimación del potencial peligroso de lodo de carbonato, la ceniza de biomasa y el lodo de la estación depuradora de aguas residuales (EDAR) se realizaron de acuerdo con la norma NBR 10004: 2004. La ceniza de biomasa y los lodos de la EDAR se clasificaron como no peligrosos (clase II), mientras que el lodo de carbonato se clasificó como peligroso (pH > 12.5, clase I). Una mezcla de estos residuos (69 % en peso de lodo de carbonato, 29 % en peso de ceniza de biomasa y 2 % en peso de lodo de EDAR) fue procesada a 1455 ºC para generar el denominado Ecoclínker. El clínker fue caracterizado, molido y mezclado con sulfato de calcio para ser utilizado como Ecocement. Los morteros fueron obtenidos y curados por períodos de 7 y 28 días. El producto endurecido mostró una resistencia mecánica de ~ 20 MPa. Las pruebas de lixiviación y pH estuvieron dentro de los límites permitidos, lo que confirma el carácter no peligroso del cemento a base de residuos.

 Keywords waste recycle clinker mortar Palabras clave reciclaje de residuos clínker mortero Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES/Brazil) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq/Brazil) The authors <bold>INTRODUCTION</bold>

The appropriate management of waste materials and the reduction of environmental loads are a critical challenge for modern society to ensure that the pillars of sustainability are met.

Generally, most of these waste materials are disposed in municipal or industrial landfill. However, the inappropriate planning and operation of these landfills may cause ground and surface water contamination by the leakage of toxic compounds. In addition, soil contamination and a repulsive odour may be generated (Saikia et al. 2007). This practice does not recover the material/energy content of the waste, nor does it contribute to the development of a sustainable economy.

Many alternative technologies have been investigated to reduce the hazard potential of certain waste streams. Stabilisation in a solid state is one of the most common processes for encapsulating toxic species in an inert matrix (such as a cement-based matrix) (Miranda et al. 2011, Modolo et al. 2011, Pinheiro et al. 2013, Siqueira and Holanda 2013). Ceramisation or vitrification may also be implemented, but they require more energy and monetary investment unless a valuable product is obtained that can mitigate these expenses (Mangialardi 2001, Park and Heo 2002, Buruberri et al. 2015).

Co-processing in clinker kilns is an efficient thermal stabilisation technique owing to the high temperature used and long residence time of gases (Saikia et al. 2007, Wang et al. 2010). These characteristics provide co-processing with more advantages than traditional incinerators as lower atmospheric emissions are produced and the environmental impacts can be minimized.

Paper pulp production generates a variety of waste types, including ash from biomass combustion, green liquor dregs, slake grits, lime mud, and WWTP sludge (Wirojanagud et al. 2004, Monte et al. 2009). Some of these wastes have been combined to produce clinker (Buruberri et al. 2015) as they may contain high amounts of CaO, Al2O3, and SiO2. The eventual organic content may also be viewed an alternative source of energy, which commonly occurs with refuse-derived fuels (Martins et al. 2007, Sun et al. 2013, Qin et al. 2015).

In general, these wastes are non-hazardous (García et al. 2008, Ribeiro 2010, Siqueira and Holanda 2013) excluding lime mud, dregs, and grits due to their high alkalinity (Nurmesniemi et al. 2005, Almeida et al. 2007, Cabral et al. 2008, He et al. 2009, Pérez-López et al. 2010, Mäkitalo 2012, Branco et al. 2013, Jia et al. 2013, Zhang et al. 2013).

Risks associated with those materials may arise when alkaline leakage occurs and the pH levels, chemical oxygen demand (COD), and sulfate concentration of contaminated water increase (Mayes and Younger 2006, Mayes et al. 2008, Gomes et al. 2016). These changes in water properties may affect light penetration and cause the destruction of aquatic ecosystems (Andrews et al. 1997, Rogerson et al. 2008, Hull et al. 2014, Gomes et al. 2016). An alkaline pH (8.5 to 10) in aquatic environments causes severe physiological disorders in most fish species as it inhibits ammonia excretion and causes it to accumulate in their tissues, resulting in with toxicity and eventually death (Saha et al. 2002, Gomes et al. 2016).

Some studies have tried to employ the high alkalinity of these materials in useful applications. For example, Wirojanagud et al. (2004) and Sthiannopkao and Sreesai (2009) treated acidic metallurgical effluents with lime mud, and achieved Zn and Hg removal efficiencies higher than 99 %, and Cu, Pb, and Cd removal efficiencies beyond 90 %. Perez-Lopes et al. (2010) used this material to treat acid mine drainage and achieved similar removal efficiencies.

In this study, balanced combinations of lime mud, biomass ash, and WWTP sludge were formulated and thermally treated to generate clinker, and the cement produced with that clinker was then used in mortars. After curing, the products were characterized in terms of their physical and mechanical properties and pH levels. Leaching tests were also conducted.

 <bold>EXPERIMENTAL</bold> <bold>Materials</bold>

The following materials were used in this work:

(i) Biomass ash, WWTP sludge (mix of primary and secondary sludge coming industry), and lime mud, to produce Ecoclinker;

(ii) Gypsum (D50 = 0.03 mm) to produce Ecocement;

(iii) Standard sand (size 1.2 mm – batch 41/2014, 0.6 mm – batch 10/2015, 0.3 mm – 14/2015 batch, and 0.15 mm – 14/2015 batch) for formulating the mortars as specified by NBR 7215: 1997 (IPT 2016).

Eucalyptus and pine trees provided biomass for obtaining cellulose through the Kraft process. Ashes were from fluidized bed burning using the same biomass.

<bold>Waste characterization</bold>

The waste was characterized by determining its moisture content, density (gravimetric method), amount of free liquids according to NBR 12988:1993 (ABNT 1993), and oils and grease (gravimetric method with extraction using an ethyl ether). The chemical composition was determined by wavelength dispersive X-ray fluorescence spectrometry (WDXRF Axios Max Panalytical), and the loss on ignition (LOI) was estimated at 1000 ºC.

The hazardous characteristics of the waste and obtained products were estimated by NBR 10004:2004 (ABNT 2004a). The wastes are classified as either hazardous (class I) or non-hazardous (class II). Non-hazardous wastes are further divided into non-inert (IIA) or inert (IIB). The tests reported in NBR 10004:2004 (ABNT 2004a) are all based on USEPA-SW 846 (USEPA 2016), and were conducted after the sample pieces were ground and sieved below 9.5 mm.

The corrosiveness, reactivity, and toxicity were evaluated to determine whether the waste would be hazardous (class I). The waste is classified as corrosive when the pH of the sample mixed with water in a 1:1 ratio is below 2 or above 12.5. The waste is designated as reactive when the concentrations of the CN– or S2– ions exceed 250 mg of HCN and 500 mg of H2S released per kg of waste, respectively. The cyanide test was conducted by colourimetry and ultraviolet-visible (UV/VIS) spectrophotometry with chloramine T/barbituric acid. The sulfide determination was performed through a preliminary distillation, and the distillate was then collected in a zinc acetate solution and titrated with sodium thiosulphate in the presence of a starch indicator.

The toxicity was determined by leaching, as described in NBR 10005:2004 (ABNT 2004b). Extraction solution 1 was used for analyzing the biomass ashes and WWTP sludge, while extraction solution 2 was used for lime mud. Extraction solution 1 contained 5.7 mL of glacial acetic acid, distilled water, and 64.3 mL of NaOH 1.0 N, while extraction solution 2 contained 5.7 mL of glacial acetic acid and distilled water. The water was added to make up the solution volume to 1 L.

To determine if the waste is non-inert (class IIA) or inert (class IIB), a solubility test was performed according to NBR 10006:2004 (ABNT 2004c). In this test, the sample was dried and distilled water was added (1000 mL of water per 250 g of sample). After 7 days, the extracts were then filtered through a 0.45-µm pore size filter.

The leached and solubilized extracts were analyzed by plasma-optical emission spectrometry-ICP (Agilent, 720–OES) and the results were compared to the limits stated in the respective standards.

<bold>Waste recycling</bold>

The wastes were used without undergoing any treatment and homogenized in 2-mm (9 mesh) and 1-mm (16 mesh) sieves. The raw mixture consisted of 69 wt % lime mud, 29 wt % biomass ash, and 2 wt % WWTP sludge. These values were selected based on preliminary studies (Simão et al. 2017). The waste was thermally treated in a furnace (Fortelab model ME 1700/V/Eg) at 1000 ºC for 120 min to promote decarbonation, and then at 1455 ºC for a further 90 min to produce Ecoclinker, with heating rates of 5 and 10 ºC/min, respectively. These conditions were determined based on the ternary diagram of CaO-SiO2-Al2O3 and the work of Buruberri et al. (2015).

The obtained Ecoclinker was chemically and mineralogically characterized by WDXRF and X-ray powder diffraction (XRD, Shimadzu XRD-6000, Japan) with CuKα radiation, 0.02º 2θ step-scan, and 10 s/step with phase quantification by Rietveld refinement, respectively.

The Ecoclinker was crushed in a ring mill after the gypsum was added (5 wt %) to form the Ecocement, with particles passing through a 45-µm filter (325 mesh sieve).

The cement potential as a binder according to NBR 5732:1991 (ABNT 1991) was validated through the formulation of mortar samples (50 mm in diameter and 100 mm in height) containing one part of Ecocement and three parts of sand in weight. The water/cement ratio (w/c) was 0.75 based on the workability tests of mortar in its fresh state. This test was conducted on a table to determine the consistency index according to NBR 7215:1996 (ABNT 1996).

Specimens were cured at room temperature for 24 h and then immersed in lime-saturated water for 28 days. After 7 and 28 days of curing, the samples were mechanically tested by compression (EMIC DL10000 machine) according to NBR 5739:2007 (ABNT 2007).

Broken pieces of the specimens that were cured for seven days were ground (< 9.5 mm) to test the pH, leaching according to NBR 10005:2004 (ABNT 2004b), and solubility based on NBR 10006:2004 (ABNT 2004c).

 <bold>RESULTS AND DISCUSSION</bold> <bold>Waste characterization</bold>

The WWTP sludge has a high moisture level (~87 wt %), therefore, only 2 wt % of this material was used in the formulation of Ecoclinker. A high moisture content in the formulation can generate problems in processing. The moisture values of the biomass ash and lime mud were ~23 and ~26 wt %, respectively. Free liquids were not identified in the waste, and the densities of the biomass ash, lime mud, and WWTP sludge were 0.36, 0.74, and 0.81 g/mL, respectively ( Table I ).

PHYSIO-CHEMICAL CHARACTERISTICS OF THE STUDIED WASTE TABLE I PHYSIO-CHEMICAL CHARACTERISTICS OF THE STUDIED WASTE

a WWTP: Waste water treatment plant

The biomass ashes exhibited a high concentration of silica (49.60 wt %), in addition to other important oxides required for the formulation of clinker, such as Al2O3 (9.94 wt %), Fe2O3 (4.07 wt %), and CaO (2.10 wt %). WWTP sludge is primarily composed of organic matter, the decomposition of which caused the high LOI (74.80 wt %). Lime mud contains 53.60 wt % CaO, confirming that is a rich source of calcite. The calcite had a LOI of 42.20 wt % ( Table II ). The CaO-SiO2-Al2O3 ternary diagram presented in figure 1 shows the position of the waste, and provides the targeted region of Portland clinker.

CHEMICAL COMPOSITIONS OF THE SAMPLES TABLE II CHEMICAL COMPOSITIONS OF THE SAMPLES

a WWTP = Waste water treatment plant, bLOI = Loss on ignition

Location of waste and Ecoclinker in the CaO-SiO<sub>2</sub>-Al<sub>2</sub>O<sub>3</sub> ternary diagram with the Portland-type clinker compositional region. (WWTP: Waste water treatment plant) Fig. 1 Location of waste and Ecoclinker in the CaO-SiO2-Al2O3 ternary diagram with the Portland-type clinker compositional region. (WWTP: Waste water treatment plant)

The lime mud waste was classified as hazardous (class I) due to its corrosive nature. The pH (12.67) of the lime mud/water mixture (1:1 w/w) exceeded the limit set by the NBR 10004:2004 standard for non-hazardous materials (2.1 to 12.5) ( Table III ). The lime mud was also characterized as nonreactive ( Table III ) and nontoxic, as all parameters evaluated in the leaching test presented values lower than those specified by the NBR 10004:2004 guideline ( Table IV ).

CORROSIVENESS AND REACTIVITY OF THE STUDIED WASTES TABLE III CORROSIVENESS AND REACTIVITY OF THE STUDIED WASTES

aBased on NBR 10004:2004, bWWTP = Waste water treatment plant

Biomass ash and WWTP sludge were also classified as noncorrosive and nonreactive as their pH values, as well as their cyanide and sulphite concentrations, were within the limits set by NBR 10004:2004 ( Table III ). These two wastes were also classified as nontoxic in the leaching test ( Table IV ).

LEACHING RESULTS OF THE STUDIED WASTE TABLE IV LEACHING RESULTS OF THE STUDIED WASTE

Blank spaces = not evaluated, aBased on Brazilian standard NBR 10004:2004, bWWTP = Waste water treatment plant

he solubility test shows that only the aluminium concentration was above the permitted value of 0.2 mg/L for biomass ashes (0.6 mg/L), thus, it was characterized as non-hazardous – class IIA – non-inert. The WWTP sludge was also classified as IIA – non-inert, as the manganese and sodium concentrations exceeded the limits of 0.1 and 200 mg/L in the solubility test, respectively, which presented values of 0.19 mg/L for manganese and 284.07 mg/L for sodium ( Table V ).

SOLUBILIZATION RESULTS OF THE STUDIED WASTE TABLE V SOLUBILIZATION RESULTS OF THE STUDIED WASTE

aBased on Brazilian standard NBR 10004:2004, bWWTP = Waste water treatment plant

<bold>Waste recycling</bold>

The chemical composition of the obtained Ecoclinker agreed well with the literature (Mehta and Monteiro 2005, Buruberri et al. 2015, Simão et al. 2017) ( Table II and Fig. 1 ), with calcium (60.33 wt %), silicon (22.70 wt %) and aluminium (6.77 wt %) oxides dominating the material’s composition.

The diffractogram ( Fig. 2 ) shows the peaks of the main crystalline phases found in the clinkers, such as the calcium silicates alite (C3S, JCPDS: 49-0442) and belite (C2S, JCPDS: 33-0302), as well as tricalcium aluminate (C3A, JCPDS: 38-1429) and ferric tetracalcium (C4AF, JCPDS: 30-0226). The Rietveld quantification showed that alite was the predominant phase (46 wt %), which is typical of Portland cement.

X-ray powder diffraction (XRD) patterns of the <italic>Ecoclinker</italic> Fig. 2 X-ray powder diffraction (XRD) patterns of the Ecoclinker

n its fresh state, the slump flow of the Ecocement-based mortar was 78.5 % using a w/c ratio of 0.75. In their hardened state, the cured mortars presented satisfactory mechanical strength in comparison to the values found in the literature (Raupp-Pereira et al. 2008, Buruberri et al. 2015) ( Fig. 2 ). They are perfectly applicable as coating mortars, which require less mechanical strength (1-2 MPa). It is also worth noting that the mechanical strength values are very close to the minimum limit (25 MPa) set by NBR 5732:1991 (ABNT 1991) for the class of 25 MPa ( Fig. 3 ). This standard specifies the mechanical strength values for common Portland cement in Brazil.

Compressive strength (MPa) of the mortars and a comparison with literature/standard results Fig. 3 Compressive strength (MPa) of the mortars and a comparison with literature/standard results

The leaching test presented no evidence of hazard ( Table VI ), therefore, the product could be classified as non-toxic and non-hazardous. Its pH (11.45) is also below the limit of corrosiveness.

PHYSIO-CHEMICAL CHARACTERISTICS OF THE MORTARS CURED FOR SEVEN DAYS TABLE VI PHYSIO-CHEMICAL CHARACTERISTICS OF THE MORTARS CURED FOR SEVEN DAYS

aBased on Brazilian standard NBR 10004:2004

The results of the solubility test of the mortar ( Table VII ) indicated that the total chromium and phenol values exceeded the limits established by NBR 10004:2004, therefore, the product was characterized as non-inert.

RESULTS OF MORTAR SOLUBILIZATION TESTS TABLE VII RESULTS OF MORTAR SOLUBILIZATION TESTS

aBased on Brazilian standard NBR 10004:2004

The results obtained for the material formulated entirely from waste indicate the feasibility of these materials to be explored by the cement industry as an alternative mineral source to produce clinkers, and of the application of these products as hydraulic binders.

 <bold>CONCLUSIONS</bold>

Chemical characterization of lime mud, biomass ash, and WWTP sludge revealed their potential to be used as raw materials in cement (high CaO, SiO2, Al2O3, and organic matter content). The conducted tests classified the waste as non-hazardous (class II), with the exception of lime mud, which had a pH > 12.5 (12.67) and was classified as corrosive (class I). These wastes were stabilized by clinkering which improved the functionality of the resultant Ecoclinker. Mortars that were cured for 28 days exhibited a mechanical resistance of ~20 MPa. The hazard test demonstrated that the pH of the mortars was < 12.5, and the leaching test indicated that the concentrations of all the compounds were within the limits set by NBR 10004:2004. The stabilisation of lime mud, biomass ashes, and WWTP sludge waste in cement matrixes and clinkers which were formulated exclusively from these materials demonstrates the potential of this method as an alternative to the current destination and treatment methods for pulp and paper mill waste.

The authors are very grateful to Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES/Brazil) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq/Brazil) for funding this work.

 <bold>REFERENCES</bold> ABNT (2007). NBR 5739. Concreto, Ensaios de compressão de corpos cilindricos, Associação Brasileira de Normas Técnicas. Standart. Rio de Janeiro, RJ, Brazil, 9 pp. ABNT NBR 5739. Concreto, Ensaios de compressão de corpos cilindricos 2007 Rio de Janeiro, RJ, Brazil Associação Brasileira de Normas Técnicas. Standart 9 ABNT (2004a). NBR 10004. Resíduos sólidos, Classificação, Associação Brasileira de Normas Técnicas. Standart. Rio de Janeiro, RJ, Brazil, 71 pp. ABNT NBR 10004. Resíduos sólidos, Classificação 2004 Rio de Janeiro, RJ, Brazil NBR 10004. Resíduos sólidos, Classificação, Associação Brasileira de Normas Técnicas. Standart 71 ABNT (2004b). NBR 10005. Procedimento para obtenção de lixiviado de resíduos sólidos, Associação Brasileira de Normas Técnicas. Standart. Rio de Janeiro, RJ, Brazil, 16 pp. ABNT NBR 10005. Procedimento para obtenção de lixiviado de resíduos sólidos 2004 Rio de Janeiro, RJ, Brazil Associação Brasileira de Normas Técnicas. Standart 16 ABNT (2004c). NBR 10006. Procedimento para obtenção de extrato solubilizado de resíduos sólidos, Associação Brasileira de Normas Técnicas. Manual. Rio de Janeiro, RJ, Brazil, 3 pp. ABNT NBR 10006. Procedimento para obtenção de extrato solubilizado de resíduos sólidos 2004 Rio de Janeiro, RJ, Brazil Associação Brasileira de Normas Técnicas. Manual 3 ABNT (1996). NBR 7215. Cimento Portland, Determinação da resistência à compressão, Associação Brasileira de Normas Técnicas. Standart. Rio de Janeiro, RJ, Brazil, 8 pp. ABNT NBR 7215. Cimento Portland, Determinação da resistência à compressão 1996 Rio de Janeiro, RJ, Brazil Associação Brasileira de Normas Técnicas. Standart 8 ABNT (1993). NBR 12988. Líquidos livres, Verificação em amostra de resíduos, Método de ensaio. Associação Brasileira de Normas Técnicas. Manual. Rio de Janeiro, RJ, Brazil, 2 pp. ABNT NBR 12988. Líquidos livres, Verificação em amostra de resíduos, Método de ensaio 1993 Rio de Janeiro, RJ, Brazil Associação Brasileira de Normas Técnicas. Manual 2 ABNT (1991). NBR 5732. Cimento Portland comum, Associação Brasileira de Normas Técnicas. Standart. Rio de Janeiro, RJ, Brazil, 5 pp. ABNT NBR 5732. Cimento Portland comum 1911 Rio de Janeiro, RJ, Brazil Associação Brasileira de Normas Técnicas. Standart 5 Almeida H.C., Da Silveira, C.B., Ernani P.R., Campos M.L. and Almeida D. (2007). Composição química de um resíduo alcalino da indústria de papel e celulose (DREGS). Quim. Nova 30 (7), 1669-1672. DOI: 10.1590/S0100-40422007000700032 Almeida H.C. Da Silveira C.B. Ernani P.R. Campos M.L. Almeida D. Composição química de um resíduo alcalino da indústria de papel e celulose (DREGS) Quim. Nova 2007 30 (7) 1669 1672 10.1590/S0100-40422007000700032 Andrews J.E., Gare S.G. and Dennis P.F. (1997). Unusual isotopic phenomena in Welsh quarry water and carbonate crusts. Terra Nov. 9 (2), 67-70. DOI: 10.1111/j.1365-3121.1997.tb00004.x Andrews J.E. Gare S.G. Dennis P.F. Unusual isotopic phenomena in Welsh quarry water and carbonate crusts Terra Nov. 1997 9 (2) 67 70 10.1111/j.1365-3121.1997.tb00004.x Branco S.B., Silveira C.B., Campos M.L., Gatiboni L.C. and Miquelluti D.J. (2013). Atributos químicos do solo e lixiviação de compostos fenólicos após adição de resíduo sólido alcalino. Rev. Bras. Eng. Agrícola e Ambient. 17 (5), 543-550. DOI: 10.1590/S1415-43662013000500012 Branco S.B. Silveira C.B. Campos M.L. Gatiboni L.C. Miquelluti D.J. Atributos químicos do solo e lixiviação de compostos fenólicos após adição de resíduo sólido alcalino Rev. Bras. Eng. Agrícola e Ambient. 2013 17 (5) 543 550 10.1590/S1415-43662013000500012 Buruberri L.H., Seabra M.P. and Labrincha J. A. (2015). Preparation of clinker from paper pulp industry wastes. J. Hazard. Mater. 286, 252-260. DOI: 10.1016/j.jhazmat.2014.12.053 Buruberri L.H. Seabra M.P. Labrincha J. A. Preparation of clinker from paper pulp industry wastes J. Hazard. Mater. 2015 286 252 260 10.1016/j.jhazmat.2014.12.053 Cabral F., Ribeiro H.M., Hilário L., Machado L. and Vasconcelos E. (2008). Use of pulp mill inorganic wastes as alternative liming materials. Bioresour. Technol. 99 (17), 8294-8298. DOI: 10.1016/j.biortech.2008.03.001 Cabral F. Ribeiro H.M. Hilário L. Machado L. Vasconcelos E. Use of pulp mill inorganic wastes as alternative liming materials Bioresour. Technol. 2008 99 (17) 8294 8298 10.1016/j.biortech.2008.03.001 García R., Vigil de la Villa R., Vegas I., Frías M. and Sánchez de Rojas M.I. (2008). The pozzolanic properties of paper sludge waste. Constr. Build. Mater. 22 (7), 1484-1490. DOI: 10.1016/j.conbuildmat.2007.03.033 García R. Vigil de la Villa R. Vegas I. Frías M. Sánchez de Rojas M.I. The pozzolanic properties of paper sludge waste Constr. Build. Mater. 2008 22 (7) 1484 1490 10.1016/j.conbuildmat.2007.03.033 Gomes H.I., Mayes W.M., Rogerson M., Stewart D.I. and Burke I.T. (2016). Alkaline residues and the environment: a review of impacts, management practices and opportunities. J. Clean. Prod. 112, 3571-3582. DOI: 10.1016/j.jclepro.2015.09.111 Gomes H.I. Mayes W.M. Rogerson M. Stewart D.I. Burke I.T. Alkaline residues and the environment: a review of impacts, management practices and opportunities J. Clean. Prod. 2016 112 3571 3582 10.1016/j.jclepro.2015.09.111 He J., Lange C.R. and Dougherty M. (2009). Laboratory study using paper mill lime mud for agronomic benefit. Process Saf. Environ. Prot. 87 (6), 401-405. DOI: 10.1016/j.psep.2009.08.001 He J. Lange C.R. Dougherty M. Laboratory study using paper mill lime mud for agronomic benefit Process Saf. Environ. Prot. 2009 87 (6) 401 405 10.1016/j.psep.2009.08.001 Hull S.L., Oty U.V. and Mayes W.M. (2014). Rapid recovery of benthic invertebrates downstream of hyperalkaline steel slag discharges. Hydrobiologia 736 (1), 83-97. DOI: 10.1007/s10750-014-1894-5 Hull S.L. Oty U.V. Mayes W.M. Rapid recovery of benthic invertebrates downstream of hyperalkaline steel slag discharges Hydrobiologia 2014 736 (1) 83 97 10.1007/s10750-014-1894-5 IPT (2016). Areia Normal Brasileira. Instituto de Pesquisas Tecnológicas [online]. http://www.ipt.br/areianormal 21/04/2018. IPT Areia Normal Brasileira 2016 Instituto de Pesquisas Tecnológicas 2018/04/21 http://www.ipt.br/areianormal Jia Y., Maurice C. and Öhlander B. (2013). Effect of the alkaline industrial residues fly ash, green liquor dregs, and lime mud on mine tailings oxidation when used as covering material. Environ. Earth Sci. 72 (2), 319-334. DOI: 10.1007/s12665-013-2953-3 Jia Y. Maurice C. Öhlander B. Effect of the alkaline industrial residues fly ash, green liquor dregs, and lime mud on mine tailings oxidation when used as covering material Environ. Earth Sci. 2013 72 (2) 319 334 10.1007/s12665-013-2953-3 Mäkitalo M. (2012). Green liquor dregs as sealing layer material to cover sulphidic mine waste deposits. Licentiate Dissertation. Luleå University of Technology. Luleå, Sweeden, 20 pp. Mäkitalo M. Licentiate Dissertation 2012 Luleå, Sweeden Luleå University of Technology Green liquor dregs as sealing layer material to cover sulphidic mine waste deposits 20 Mangialardi T. (2001). Sintering of MSW fly ash for reuse as a concrete aggregate. J. Hazard. Mater. 87 (1-3), 225-239. DOI: 10.1016/S0304-3894(01)00286-2 Mangialardi T. Sintering of MSW fly ash for reuse as a concrete aggregate J. Hazard. Mater. 2001 87 (1-3) 225 239 10.1016/S0304-3894(01)00286-2 Martins F.M., Martins J.M., Ferracin L.C. and da Cunha C.J. (2007). Mineral phases of green liquor dregs, slaker grits, lime mud and wood ash of a Kraft pulp and paper mill. J. Hazard. Mater. 147 (1-2), 610-617. DOI: 10.1016/j.jhazmat.2007.01.057 Martins F.M. Martins J.M. Ferracin L.C. da Cunha C.J. Mineral phases of green liquor dregs, slaker grits, lime mud and wood ash of a Kraft pulp and paper mill J. Hazard. Mater. 2007 147 (1-2) 610 617 10.1016/j.jhazmat.2007.01.057 Mayes W.M. and Younger P.L. (2006). Buffering of alkaline steel slag leachate across a natural wetland. Environ. Sci. Technol. 40 (4), 1237-1243. DOI: 10.1021/es051304u Mayes W.M. Younger P.L. Buffering of alkaline steel slag leachate across a natural wetland Environ. Sci. Technol. 2006 40 (4) 1237 1243 10.1021/es051304u Mayes W.M., Younger P.L. and Aumônier J. (2008). Hydrogeochemistry of alkaline steel slag leachates in the UK. Water. Air. Soil Pollut. 195 (1-4), 35-50. DOI: 10.1007/s11270-008-9725-9 Mayes W.M. Younger P.L. Aumônier J. Hydrogeochemistry of alkaline steel slag leachates in the UK Water. Air. Soil Pollut. 2008 195 (1-4) 35 50 10.1007/s11270-008-9725-9 Mehta P.K. and Monteiro P.J.M. (2005) Concrete: Microstructure, properties, and materials. 3rd ed. McGraw-Hill Professional. New York City, USA. 659 pp. Mehta P.K. Monteiro P.J.M. Concrete: Microstructure, properties, and materials 2005 New York City, USA McGraw-Hill Professional 3rd ed. 659 Miranda L. de A., Alvarenga R. de C.S.S., Pinto P.C.M.J., Junior E.D. de P., Carvalho C.A.B., Fassoni D.P. and Couto L.G. (2011). Avaliação do potencial do grits como material de construção na produção de tijolos de solo-cimento. Rev. Árvore 35 (6), 1335-1340. DOI: 10.1590/S0100-67622011000700020 Miranda L. de A. Alvarenga R. de C.S.S. Pinto P.C.M.J. Junior E.D. de P. Carvalho C.A.B. Fassoni D.P. Couto L.G. Avaliação do potencial do grits como material de construção na produção de tijolos de solo-cimento Rev. Árvore 2011 35 (6) 1335 1340 10.1590/S0100-67622011000700020 Modolo R., Senff L., Ferreira V.M., Labrincha J.A. and Tarelho L.A. (2011). Use of lime-mud from pulp mill plant in cement-mortars. In: 1st International Conference of Wastes: Solutions, Treatments and Oportunities. Guimarães, Portugal. Modolo R. Senff L. Ferreira V.M. Labrincha J.A. Tarelho L.A. Use of lime-mud from pulp mill plant in cement-mortars 2011 Guimarães, Portugal 1st International Conference of Wastes: Solutions, Treatments and Oportunities Monte M.C., Fuente E., Blanco A. and Negro C. (2009). Waste management from pulp and paper production in the European Union. Waste Manag. 29 (1), 293-308. DOI: 10.1016/j.wasman.2008.02.002 Monte M.C. Fuente E. Blanco A. Negro C. Waste Manag. 2009 29 (1) 293 308 Waste management from pulp and paper production in the European Union 10.1016/j.wasman.2008.02.002 Nurmesniemi H., Pöykiö R., Perämäki P. and Kuokkanen T. (2005). The use of a sequential leaching procedure for heavy metal fractionation in green liquor dregs from a causticizing process at a pulp mill. Chemosphere 61 (10), 1475-1484. DOI: 10.1016/j.chemosphere.2005.04.114 Nurmesniemi H. Pöykiö R. Perämäki P. Kuokkanen T. The use of a sequential leaching procedure for heavy metal fractionation in green liquor dregs from a causticizing process at a pulp mill Chemosphere 2005 61 (10) 1475 1484 10.1016/j.chemosphere.2005.04.114 Park Y.J. and Heo J. (2002). Vitrification of fly ash from municipal solid waste incinerator. J. Hazard. Mater. 91 (1-3), 83-93. DOI: 10.1016/S0304-3894(01)00362-4 Park Y.J. Heo J. Vitrification of fly ash from municipal solid waste incinerator J. Hazard. Mater. 2002 91 (1-3) 83 93 10.1016/S0304-3894(01)00362-4 Pérez-López R., Castillo J., Quispe D. and Nieto J.M. (2010). Neutralization of acid mine drainage using the final product from CO2 emissions capture with alkaline paper mill waste. J. Hazard. Mater. 177 (1-3), 762-72. DOI: 10.1016/j.jhazmat.2009.12.097 Pérez-López R. Castillo J. Quispe D. Nieto J.M. Neutralization of acid mine drainage using the final product from CO2 emissions capture with alkaline paper mill waste J. Hazard. Mater. 2010 177 (1-3) 762 772 10.1016/j.jhazmat.2009.12.097 Pinheiro M.L., Alvarenga R. de C.S.S.A., Ribeiro B.C., Júnior P.R.S., Sarmet M.S. and Fassoni D.P. (2013). Avaliação experimental de blocos prensados de solo-cimento com adição de grits. Ambient. Construído 13 (2), 29-35. DOI: 10.1590/S1678-86212013000200004 Pinheiro M.L. Alvarenga R. de C.S.S.A. Ribeiro B.C. Júnior P.R.S. Sarmet M.S. Fassoni D.P. Avaliação experimental de blocos prensados de solo-cimento com adição de grits Ambient. Construído 2013 13 (2) 29 35 10.1590/S1678-86212013000200004 Qin J., Cui C., Cui X., Hussain A., Yang C. and Yang S. (2015). Recycling of lime mud and fly ash for fabrication of anorthite ceramic at low sintering temperature. Ceram. Int. 41 (4), 5648-5655. DOI: 10.1016/j.ceramint.2014.12.149 Qin J. Cui C. Cui X. Hussain A. Yang C. Yang S. Recycling of lime mud and fly ash for fabrication of anorthite ceramic at low sintering temperature Ceram. Int. 2015 41 (4) 5648 5655 10.1016/j.ceramint.2014.12.149 Raupp-Pereira F., Ball R.J., Rocha J., Labrincha J. A. and Allen G.C. (2008). New waste based clinkers: Belite and lime formulations. Cem. Concr. Res. 38 (4), 511-521. DOI: 10.1016/j.cemconres.2007.11.008 Raupp-Pereira F. Ball R.J. Rocha J. Labrincha J. A. Allen G.C. New waste based clinkers: Belite and lime formulations Cem. Concr. Res. 2008 38 (4) 511 521 10.1016/j.cemconres.2007.11.008 Ribeiro A.P. (2010). Avaliação do uso de resíduos sólidos inorgânicos da produção de celulose em materiais cerâmicos. Tese de doutorado. Escola Politécnica da Universidade de São Paulo. São Paulo, Brasil, 142 pp. Ribeiro A.P. Tese de doutorado 2010 São Paulo, Brasil Escola Politécnica da Universidade de São Paulo Avaliação do uso de resíduos sólidos inorgânicos da produção de celulose em materiais cerâmicos 142 Rogerson M., Pedley H.M., Wadhawan J.D. and Middleton R. (2008). New insights into biological influence on the geochemistry of freshwater carbonate deposits. Geochim. Cosmochim. Acta 72 (20), 4976-4987. DOI: 10.1016/j.gca.2008.06.030 Rogerson M. Pedley H.M. Wadhawan J.D. Middleton R. New insights into biological influence on the geochemistry of freshwater carbonate deposits Geochim. Cosmochim. Acta 2008 72 (20) 4976 4987 10.1016/j.gca.2008.06.030 Saha N., Kharbuli Z.Y., Bhattacharjee A., Goswami C. and Häussinger D. (2002). Effect of alkalinity (pH 10) on ureogenesis in the air-breathing walking catfish, Clarias batrachus. Comp. Biochem. Physiol. Part A Mol. Integr. Physiol. 132 (2), 353-364. DOI: 10.1016/S1095-6433(02)00044-2 Saha N. Kharbuli Z.Y. Bhattacharjee A. Goswami C. Häussinger D. Effect of alkalinity (pH 10) on ureogenesis in the air-breathing walking catfish, Clarias batrachus Comp. Biochem. Physiol. Part A Mol. Integr. Physiol. 2002 132 (2) 353 364 10.1016/S1095-6433(02)00044-2 Saikia N., Kato S. and Kojima T. (2007). Production of cement clinkers from municipal solid waste incineration (MSWI) fly ash. Waste Manag. 27 (9), 1178-1189. DOI: 10.1016/j.wasman.2006.06.004 Saikia N. Kato S. Kojima T. Production of cement clinkers from municipal solid waste incineration (MSWI) fly ash Waste Manag. 2007 27 (9) 1178 1189 10.1016/j.wasman.2006.06.004 Simão L., Jiusti J., Lóh N.J., Hotza D., Raupp-Pereira F., Labrincha J.A. and Montedo O.R.K. (2017). Waste-containing clinkers: Valorization of alternative mineral sources from pulp and paper mills. Process Saf. Environ. Prot. 109, 106-116. DOI: 10.1016/j.psep.2017.03.038 Simão L. Jiusti J. Lóh N.J. Hotza D. Raupp-Pereira F. Labrincha J.A. Montedo O.R.K. Waste-containing clinkers: Valorization of alternative mineral sources from pulp and paper mills Process Saf. Environ. Prot. 2017 109 106 116 10.1016/j.psep.2017.03.038 Siqueira F.B. and Holanda J.N.F. (2013). Reuse of grits waste for the production of soil-cement bricks. J. Environ. Manage. 131, 1-6. DOI: 10.1016/j.jenvman.2013.09.040 Siqueira F.B. Holanda J.N.F. Reuse of grits waste for the production of soil-cement bricks J. Environ. Manage 2013 131 1 6 10.1016/j.jenvman.2013.09.040 Sthiannopkao S. and Sreesai S. (2009). Utilization of pulp and paper industrial wastes to remove heavy metals from metal finishing wastewater. J. Environ. Manage. 90, 3283-3289. DOI: 10.1016/j.jenvman.2009.05.006 Sthiannopkao S. Sreesai S. Utilization of pulp and paper industrial wastes to remove heavy metals from metal finishing wastewater J. Environ. Manage. 2009 90 3283 3289 10.1016/j.jenvman.2009.05.006 Sun R., Li Y., Liu C., Xie X. and Lu C. (2013). Utilization of lime mud from paper mill as CO2 sorbent in calcium looping process. Chem. Eng. J. 221, 124-132. DOI: 10.1016/j.cej.2013.01.068 Sun R. Li Y. Liu C. Xie X. Lu C. Utilization of lime mud from paper mill as CO2 sorbent in calcium looping process Chem. Eng. J. 2013 221 124 132 10.1016/j.cej.2013.01.068 USEPA (2016). SW 846. Hazardous Waste Test Methods. United States Environmental Protecion Agency. Manual. Washington, D.C., USA, 295 pp. USEPA SW 846. Hazardous Waste Test Methods 2016 Washington, D.C., USA United States Environmental Protecion Agency. Manual 295 Wang L., Jin Y., Nie Y. and Li R. (2010). Recycling of municipal solid waste incineration fly ash for ordinary Portland cement production: A real-scale test. Resour. Conserv. Recycl. 54 (12), 1428-1435. DOI: 10.1016/j.resconrec.2010.06.006 Wang L. Jin Y. Nie Y. Li R. Recycling of municipal solid waste incineration fly ash for ordinary Portland cement production: A real-scale test Resour. Conserv. Recycl. 2010 54 (12) 1428 1435 10.1016/j.resconrec.2010.06.006 Wirojanagud W., Tantemsapya N. and Tantriratna P. (2004). Precipitation of heavy metals by lime mud waste of pulp and paper mill. Songklanakarin J. Sci. Technol. 26 (suppl 1), 45-53. Wirojanagud W. Tantemsapya N. Tantriratna P. Precipitation of heavy metals by lime mud waste of pulp and paper mill Songklanakarin J. Sci. Technol. 2004 26 45 53 (suppl 1) Zhang J., Wang Q. and Jiang J. (2013). Lime mud from paper-making process addition to food waste synergistically enhances hydrogen fermentation performance. Int. J. Hydrog. Energy 38 (6), 2738-2745. DOI: 10.1016/j.ijhydene.2012.12.048 Zhang J. Wang Q. Jiang J. Lime mud from paper-making process addition to food waste synergistically enhances hydrogen fermentation performance Int. J. Hydrog. Energy 2013 38 (6) 2738 2745 10.1016/j.ijhydene.2012.12.048