**1. Introduction**

The disposal of hazardous sludge is much significant in landfill waste management, covering and dumping. The reactive chemistry of sludge threats ecology even in a landfill [1–4]. There are many hazardous wastes such as the muddy by-product from the heat-treated steel manufacturing with CN baths [1–4], textile painting [1–4] and tanning sludge metal peroxide salts [5, 6], radioactive fuel waste sludge [7, 8], heavy peat of pulp washing industry [1–4].

The runoff mine phosphate ores are calcined for the production of reactive phosphate compound before conversion of phosphoric acid in the production of superphosphate fertilizer in Mazıdağı Etibakır Plant [9, 10]. However, the Cu ores from Küre and Şirvan are transferred to Mazıdağı Etibakır Cu ore stockpiles field and dissociated from Electrowinning Plant and Sulphuric acid Dissolution units. Cu is recovered by electrolysis and spent acid solutions of dissolution and electrowinning are decanted and sludge effluent is collected in the two different tailing ponds [1–4]. Under the atmospheric conditions of hard wintertime, during the time of heavy raining months in Mazıdağı, Mardin province of Southeast Anatolian Region, phosphate plant production facilities located need clean irrigation water and a hundred meter away, the freshwater reservoir of Mazıdağı town is located. The economical value of this reservoir reduces the cost of living, agricultural irrigation and animal farming in the town with a low population of about 7400 [1–4]. Effective wastewater management of high capacity of Cu dissolution plant will not threaten the scarce freshwater potential of the town and provide the much clean ecology. The spent sludge of sulfuric acid in Cu leaching is advantageous for the Co recovery process. There is a resulting heavy sludge waste of electrolysis rich with Fe, Pb, Cd and Zn. This black metal sludge is used for extraction of metals such as Au and Co. However, the recycling dissolution results in a high solute level of Pb, Hg Zn, Cd and Fe during recovering Co. This vitrification method provided a new idea for the hazardous sludge disposal in recycling plants with char/coal slime use by sludge waste.

In this study, the sludge samples of tailing ponds 1 and 2 were economically heated by microwave oven as briquettes of 50 mm size homogenously mixed with sodium silicate in the 16% porous structure and even Şırnak asphaltite slime mixed reduces metal contamination in the wet sludge of the tailing ponds. The development of compaction stress reduces the porosity of briquettes and provides a much higher strength for vitrified block formation and much possible inert-vitrified briquette yield for landfilling. Particularly in this study, the Şırnak asphaltite slimes and oak wood char subjected to the fine screening under 0.2 mm and carbon ability over Pb and Fe contamination were investigated as weight rate.

#### **1.1 Hazardous acidic leaching waste sludges**

Neutralization of acidic waste effluents is washed, and settled precipitated metal sulfates and lime iron hydrates form sludge in the oxide micron-sized hydrates in a muddy state. However, the filtrated matter containing the sulfate part of the reaction [7–9] may cause redox effect oxidation. Then

$$\mathrm{H\_2S} + 4\mathrm{H\_2O} \to \mathrm{SO\_4}^{2-} + 10\mathrm{H^+} + 8\mathrm{e^-}.\tag{1}$$

$$\mathrm{PbS} + 2\mathrm{Fe^{3+}} + 3\mathrm{SO\_4}^{2-} \sim + 3/2\mathrm{O\_2} + \mathrm{H\_2O} \to \mathrm{PbSO\_4} + 2\mathrm{Fe^{2+}} + 2\mathrm{H^{4+}} + 3\mathrm{SO4}^{2-}.\tag{2}$$

$$\mathrm{ZnS} + 2\mathrm{Fe^{3+}} + 3\mathrm{SO\_4}^{2-} \sim + 3/2\mathrm{O\_2} + \mathrm{H\_2O} \to \mathrm{ZnSO\_4} + 2\mathrm{Fe^{2+}} + 2\mathrm{H^{4+}} + 3\mathrm{SO4}^{2-}.\tag{3}$$

The heavy metal contents such as Pb and Hg are dissolved in the use of lower pH acidic solutions of H2SO4 or HNO3 in the electrolysis mud recycling leaching end as regards Pb heavy metal contamination is followed by equation, where HNO�<sup>2</sup> <sup>3</sup> nitrate concentration in the effluent

*Microwave Vitrification of Hazardous Sludge by Şırnak Asphaltite Slime… DOI: http://dx.doi.org/10.5772/intechopen.101888*

$$\frac{dc\_{Pb}}{dt} = k\_i c^{\text{int}}.dc.f\_i \left(\text{HNO}\_3^{-2}\right)^{\text{int}} \tag{4}$$

2CaOðFe2O3*=*Al2O3*:*MgO Si8O20ð Þ OH <sup>4</sup>*:*nH2O þ 2NaS2O4 <sup>2</sup>� <sup>þ</sup> 2H2O \$ 2NaCaOðFeO Fe2O3*:* Al2O3MgO*:*Si8O20 ð Þ OH <sup>4</sup>*:*nH2O þ SO3 <sup>2</sup>� <sup>þ</sup> 4H<sup>þ</sup> (5)

$$\text{Clay}-\text{Fe}^{3+} + 4\text{NO} \text{3/SO}\_4^{2-} \leftrightarrow \text{Clay}-\text{Ferrous} + 2\text{S}\_2\text{O}\_4^{2-} + \text{H}\_2\text{O} \to 2\text{SO}\_3^{2-} + \text{S}\_2\text{O}\_3^{2-} + 2\text{H}^+ \tag{6}$$

$$\text{Fe}^{2+} + \text{Pb}/\text{Zn}/\text{MnO}\_4^{2-} + \text{HNO}\_3 + 4\text{ H}\_2\text{O} \rightarrow (\text{Fe}\_2\text{2Cr}\_{1-x})(\text{OH})\_3 + \text{5OH} - \tag{7}$$

The dissolution kinetics of soil mud particle for Pb, MnO2 heavy metal is followed by Eq. (7)

where CPb, CaO, MnO2 dissolution mg/l, k the rate of digesting of lead, i is the reaction style, t is time.

The digesting amount of heavy metal in aliquate of solute of tailing pond as regarding sludge contamination is managed by equation, where n is the kinetic order type as given below

$$\frac{d\mathcal{L}\_{\rm ACOO}}{dt} = k\_i \mathfrak{c}^{\rm tPb} dc \tag{8}$$

İndustrial hazardous waste effluents threaten the agricultural land and freshwater reservoirs in a high-risk concern with relationship between the collection of wastewater through the sewage network of urbanization, the hazardous sludge treatment, transmission to decantation, disposal treatment and discharge style. Hazardous sludge and effluent management with projection on neutralization and decantation never avoid the harmful end of the sewage output, and toxic substances still exist. Regarding hydroelectricity dams, animal farming freshwater lakes are located near highly populated cities, where water management taxes, loans and low-interest loans use discounts as well as other financial support mechanisms. Hazardous sludge and effluent discharge management are so much extra critical in the way of financial consideration for public health and ecology [10–15].

#### **1.2 Hazardous sludge**

The industrial effluents with hazardous sludges are subjected to clean filtering in a continuous flow system. The hazardous effluent is decanted and followed to a best sorption process and the resulted sludge of sorption and filtered neutralization sludges show that a high amount of lime and hazardous metal salts are suitable for the vitrification of hazardous sludges for disposal. At landfill areas, the vitrified products should protect their form without cracking and digesting the hazardous content down to the irrigation or freshwater limits defined by the ecology legislation, with mg/l metal Fe.

The Fe analyses were performed with the sludge original samples and vitrified samples of different weight rate vitrifying binder to determine the duration period as leaching kinetics of Fe and Zn metals on the dissolved briquettes. The results show that Fe oxides, hydroxides, sulfates, Zn oxides, hydroxides and carbonates sulfates were dependent on ion exchange ability with lime Ca, the Zn retention occurs by crystallization as hydrozincite, and Zn5(OH)– (CO3) <sup>2</sup>– and ferric hydroxide crystallizes on neutralization sludge lime coated as ferric hydrate /zinc oxide hydrocarbonate.


#### **Table 1.**

*Values of samples at thermal dissolution [16] over 100o C.*

However, Pb sulfate and hydroxide cover are also observed in the sludges at less rates depending on the electropotential of pH values over porosity of sludge formed from clusters of ferric iron oxide and lime solids (**Table 1**) [16].

Sulfite oxidation kinetic rate is developed as given below Eq. (9),

$$\mathbf{r} = \mathbf{k} \sqrt{S/} (\text{SO3})^{2-} \left\{ (\text{O})^{2-} - \left[ (\text{O})^{2-} / (\text{SO3})^{2-} K\_{sol} \right]^{2} \right\},\tag{9}$$

where Ksol is dissolution equilibrium constant, and SO3 <sup>2</sup>– and O2– solute concentrations of sulfite and oxygen are dissolved.

The mass diffusion of cracked bonds of hydrocarbon aromatic apolar reactive sites raises the kinetic rate of dissolution through porous coal texture, while asphaltite massive texture avoids the dissolution.

Specification and sorption for risk assessment, [17–19] modeling and application for hazardous waste management should be considered over legitimate rules regarding:

radioactive decay

complexation reactions; hydrolysis, dissociations, association polymerization, oxidation redox reactions may cover hazardous components in those reactions

precipitation co-precipitation, inclusions, surface precipitation physical and chemical sorption on surface formative solids ion exchange extraction colloid formation biosorption

#### **1.3 Vitrification silicate**

The microwave vitrification studies of Cu, Zn, Pb and Fe were conducted on tailing pond sludges of pools 1 and 2 of Mazıdağı Etibakır Cu recovery plant to determine the efficiency of briquetting and strength of blocks. The resulted blocks are in the form of vitrified conventional heating and microwave heating during retention

#### *Microwave Vitrification of Hazardous Sludge by Şırnak Asphaltite Slime… DOI: http://dx.doi.org/10.5772/intechopen.101888*

time. The melting capacity of Na silicate for these sludges commonly presents the dissolution ability in the landfill area.

The window glass production technology includes the crushing-grinding, screening, washing and sand flotation unit following a very fine 200 micron and Fe % grade of sand decreased to below 0.5%, while vitrification does not need clean sand, and even dirty recycled glass waste is evaluated [20–23]. Thus, to provide vitrified matter, the cement retort kiln or firing grate furnace produces sintered waste material, homogeneous, vitrified and suitable landfill slag material. The suitable slag by-product without landfilling can be used as aggregate in asphalt road pavement and masonry stone production with low costs. Asphalt pasting of hazardous sludges is also becoming another covering method to avoid heavy metal contamination [24–28]. Şırnak asphaltite slime is already below 100-micron size and so easily mixed to cover sludge in microwave radiation. The recycled bottle waste glass and the broken window should be easily evaluated as aggregate. The shale waste of Şırnak asphaltite coal quarries reaching over 7 million tons may be evaluated as vitrification binder following grinding [29]. This vitrifying method costs less. In this study, negative effects on the vitrification quality and capacity are determined. Şırnak asphaltite slime properties are also important for vitrified briquette breakage and porosity, and surface area change.

Instead of the use of conventional grate firing, microwave vitrification is becoming advantageous in internal surface covering by inner volume heating by radiation of sludge fine solids mixed with Na silicate fine and coal slimes avoiding contamination.

#### **1.4 Microwave heating**

Microwave radiation conducts the waves through the material as radio wave frequency in tri-band microwave frequency (UHF: 300 MHz to 3 GHz), super high frequency (SHF: 3 GHz and 30 GHz) and extremely high frequency (EHF 30 GHz to 300 GHz) [11]. The microwaves pass through the whole inner depth of the diamagnetic solid texture [30–34]. The iron oxides such as wustite, magnetite and hematite can be heated in 20–30 sec at 2–3 mm size, while plastic materials isolate the waves [31]. The metallic salts such as Pb and Zn oxide or semi-metallic sulfides behave similarly as ferrous solids with high emissivity ın electromagnetic energy [32], in which solid temperature increases the temperature of whole sample volume, unlike conventional heating [33, 34].

Mineral packed in solid-densed form is easily heated under the radiation of microwave with high-frequency vibrations of inner atomic layers in mineral crystal and thermal energy increase conducts the heat from core to surface of particle grain. The heat-covered surface raises the temperature and creates an effect of melting of surface and sintering particles in the microwave vitrification of oxide solids. The studies showed that iron-bearing ores, roasting of sulfides, refractory gold concentrate oxidation, and activated carbon regeneration can be accomplished by microwave radiation in the shortest time periods between 30 sec. and 3 min [31]. The microwave heating slightly affects the calcination of limestone rock in 30 min.

Microwave act on minerals was determined to be sufficient [33–43]. Microwave interaction parameters on mineral crystals, microwave penetration level, the vibration of mineral grains, grain boundary heating, and heat absorption were managed. The thermal effects vary according to microwave-radiated mineral species [44]. The least penetration of mineral grains of quartz is given in **Table 2** and has 79<sup>o</sup> C a temperature change.


#### **Table 2.**

*Microwave temperature effect on minerals [45].*

Quality of vitrified briquettes—efficiency of vitrification.

High-intensity microwave radiation provides high-thermal inner particle surface melting Na silicate over 300<sup>o</sup> C such as low-temperature glazing. The microwave act as a sintering bound of particles of hazardous oxide and sulfate salts of dissolved sludge with heavy metals such as Pb, Cu, Zn, Fe. The vitrified glassy product contains 16–12% Na coming from melting Na silicate behaving highly transparent liquid interactive conduction heating. A high duration period will also recrystallize Na silicate binding phase. The strength of briquettes will be reduced by breaking the act of lime and Ca hydrates, and carbonates. The addition of Şırnak asphaltite slime and Şırnak shale as clay stone fines was examined in this study. The effect of microwave radiation on vitrification ability and the qualities of briquettes of this mixture was investigated.

Industrial hazardous sludges and wastewater effluents from the metal coating, Zngalvanizing effluents and other hydrometallurgical processes generally contained high levels of heavy metals such as Pb, Zn, Cr, Hg, Cd, Fe [46–48]. The vitrified matter encapsulates this hazardous salty solid-precipitated matter in a mixture of bound silicate cover. Hence, the hazard of heavy metal dissolution is avoided. The dissolution of vitrified heavy metal salts shows the quality of vitrification. Current encapsulation technology is also advantageous for radioactive sludge However, the other methods following precipitation, ionic exchange and covering or melting in synthetic resins, plastics require high-cost processing and operational costs even still create waste disposal issues. The vitrification method is usually capable of proving the limits of legislation of below 0.1 and 3 mg/l for Pb, Zn, Cd and Cd metal values [49–51]. The hazardous metal precipitation is not sufficient in neutralization and decantation down to the legal limits because organic and inorganic complex compounds allowed effluent levels above those regarding the solubility of the metal hydroxides [52–57]. Recycling of heavy metals based on vitrification may also be suggested as an alternative approach.

*Microwave Vitrification of Hazardous Sludge by Şırnak Asphaltite Slime… DOI: http://dx.doi.org/10.5772/intechopen.101888*
