# Inorganic Waste Generated in Kraft Pulp Mills:
## 4 Potential Applications
### Slaker Grits  
SG along with GLD represents a significant fraction of solid wastes generated by the pulp and paper industry [17; 34]. Table 7 presents a list of potential applications for SG.  
The high content of calcium carbonate in SG, which is an essential component of several construction materials, provides good potential for mixing/replacing traditional raw materials in  
\begin{table}
\begin{tabular}{p{142.3 pt} p{142.3 pt} p{142.3 pt}} \hline \hline
**Application** & **Highlights** & **Scale** \\ \hline Construction materials & & \\ \hline
**Cement** & The incorporation of SG up to 10\% presents good results of compressive strength and elasticity modulus to produce Portland cement (CP I-S and CP II-F) [50]. & Laboratory \\
**Clinker production** & The incorporation of 0.25 wt \% of SG shows the potential to be directly incorporated in clinker manufacture [34]. & Industrial \\
**Ceramic wall tiles** & The total replacement of traditional calcareous material by SG revealed a positive influence on the properties and microstructure of wall tiles [60]. & Laboratory \\
**Ceramic building materials** & SG can replace up to 20 wt \% Portland cement in soil-cement bricks [33]. & Laboratory \\
**(soil-cement bricks)** & & \\ \hline Geotechnical & & \\ \hline
**Road pavement construction** & Incorporation as aggregates in bituminous mixtures revealed a good performance and it might be directly tested industrially [36]. & Laboratory \\ Mixtures of GLD and SG as a natural filler and fine aggregates in bituminous mixtures have the possibility to be scaled up with success [61]. & Mixtures of GLD and SG as a natural filler and fine aggregates in bituminous mixtures have the possibility to be scaled up with success [61]. & Laboratory \\ \hline Environmental & & \\ \hline
**Acid mine drainage** & Metal removal and neutralization of acid mine drainage (AMD) in treatment systems can be controlled by the addition of alkaline SG [62; 63]. & Laboratory \\
**Landfill cover** & A mixture of GLD (70\%) and SG (30\%) was used as covering material. COD removal in the leachates (91\%) after 15 months suggest no impact on the microorganisms responsible for the stabilization of the organic fraction of the MSW [27]. & Industrial \\ \hline Agricultural & & \\ \hline
**Soil amendment and fertilizer** & A mixture of SG and green liquor sludge (7 t/ha) buffered soil acidity [38]. 0.96 tons of SG would be required to replace 1 ton of a commercial ground limestone product [63]. & Laboratory \\ \hline \hline \end{tabular}
\end{table}
Table 7: Applications of SG reported in the literature.  
these applications. At the industrial scale, the incorporation of SG directly in clinker manufacture was successfully tested with good results [34]. Since SG presents a comparable size to the crushed limestone, it can replace 100% of the filler or up to 100% of the fine aggregate for asphalt pavement. A section of 250 m length of a road in Portugal is going to be constructed using SG from pulp and paper mills [59]. Additionally, [PERSON] et al. [27] proposed an innovative strategy for the reuse of SG as municipal sanitary landfill interoperating covering. Tests at the industrial scale suggest several environmental advantages, such as heavy metal adsorption, minimization of land degradation and minimization of the landfill disposal of this waste [27]. Furthermore, the strongly alkaline pH, high calcium concentration, the existence of calcite (CaCO\({}_{3}\)), the neutralizing value [64], as well as the concentration of potentially toxic metals [65] make of SG an interesting material for application in agriculture and forestry as a soil amendment and fertilizer.