# Inorganic Waste Generated in Kraft Pulp Mills:
## 3 Main Properties of the Inorganic Wastes
### Physico-chemical properties  
In order to find the best applications for the wastes considered, in addition to the elemental composition and minerals indicated in Tables 2 and 3, the knowledge of other physical and chemical properties is fundamental, such as those reported in Table 4.  
The moisture content can vary in GLD, SG, and LM, depending on the technology and operating conditions in the pulp mill. High moisture content can be advantageous depending on the application, namely to decrease the release of dust in handling operations. However, transportation costs can be \begin{table}
\begin{tabular}{c c c c} \hline \hline
**GLD** & **SG** & **LM** & **BFA** \\ \hline Calcite (CaCO\({}_{3}\)) [4; 24; 31] & Calcite (CaCO\({}_{3}\)) [5; 24; 31] & Calcite (CaCO\({}_{3}\)) [31] & Calcite (CaCO\({}_{3}\)) [5; 23] \\ Dolomite (CaMg(CO\({}_{3}\))\({}_{2}\)) [23] & Dolomite (CaMg(CO\({}_{3}\))\({}_{2}\)) [23] & Ca(1\(-x\))MgCO [31] & Dolomite (CaMg(CO\({}_{3}\))\({}_{2}\)) [23] \\ Cesanite (Ca\({}_{2}\)Na\({}_{3}\)(SO\({}_{3}\)OH)) [23] & Quarz (SiO) [24] & Halite (NaCl) [23] \\ Natherite (Na\({}_{2}\)Ca(CO\({}_{3}\))\({}_{2}\).2H\({}_{2}\)O) [4; 21; 30] & Prismonite (Na\({}_{2}\)Ca(CO\({}_{3}\))\({}_{2}\).2H\({}_{2}\)O) [31] & Quarz (SiO) [5; 23; 31] \\ Pirssonite (Na\({}_{2}\)Ca(CO\({}_{3}\))\({}_{2}\).2H\({}_{2}\)O) [4; 21; 30] & Portalonite (Ca(OH)\({}_{2}\)) [31] & Sylvite (KCl) [23] \\ Manganite (Mn\({}_{2}\)O\({}_{3}\)H\({}_{2}\)) [4] & Wustite (FeO) [31] & Anhydrite (CaSO\({}_{3}\)) [23] \\ Sodium sesquicarbonate (Na\({}_{3}\)H\({}_{2}\)(CO\({}_{3}\))\({}_{2}\)) [15] & Larnite (Ca\({}_{2}\)SiO\({}_{3}\)) [31] & Portalonite (Ca(OH)\({}_{2}\)) [23] \\ Brucite (Mg(OH)\({}_{2}\)) [5] & Brucite (Mg(OH)\({}_{2}\)) [31] & & Periclase (MgO) [23] \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Mineral phases in GLD, SG, LM, and BFA identified by XRD. higher, as well as the difficulties in mixing with other powdered materials (for example, clay, and cement). BFA is usually generated with very low moisture, while showing high hydrophilic properties and easily forming agglomerates [32]. A key property to define the best application of a specific material is the pH. In this case, the four wastes are alkaline, and very high values (\(>\)13) can be observed in certain cases (e.g., for SG). Thus, if not properly managed, they can cause corrosion and ecotoxicity problems in natural ecosystems. However, this property may also be positive in certain applications, for example, to be used as neutralizing agents, limiting applications or as operating supply in applications that normally use alkaline raw materials (e.g., cement). BFA reveals an average pH of 11, but can vary between 8 and 13 [32]. From the electrical conductivity (EC) it is possible to infer the total concentration of dissolved electrolytes (or total dissolved solids, TDS) in aqueous suspension. In this context, it is important to note that some applications do not allow high ionic strength (applications as liming agent), but if the waste is used in bound materials (e.g., in cement formulations) this would not be a problem. [PERSON] et al. [19] measured a concentration of TDS equal to 88.5 g/kg in SG leachates, which exceed both the EU limits for inert waste landfill (4 g/kg) and the non-hazardous waste landfill (60 g/kg dw). The organic matter or volatile solids (VS determined at 550 \({}^{\circ}\)C for 2-4 h until constant weight) is in general low (much less than 8%) in all these wastes, which are then classified as inorganic. The acid neutralization capacity (ANC) or alkalinity or buffering capacity of GLD, SG, and LM is typically high. This property can be measured as calcium carbonate equivalents and as can be seen in Table 4, values close to 100% can be obtained for GLD, SG, and LM, while lower values are common for BFA [25]. [PERSON] et al. [37] reported that to keep pH \(>\) 6, the average ANC was 18.5 mmol H+/g for GLD.