# Complex Processing of Saponite Waste from a Diamond-Mining Enterprise
## 7 Synthesis of Inorganic Precipitant
Reactions that occur at the end of the induction period are the following:  
\[\text{Ca}^{2+}+2\text{OH}^{-}\rightarrow\text{Ca(OH)}_{2} \tag{7}\]  
\[2\text{SiO}_{4}^{4-}\overset{\text{H}}{\rightarrow}\text{Si}_{2}\text{O}_{7} ^{6-}+2\text{OH}^{-}\rightarrow[\text{SiO}_{3}]\ _{n}^{2-}+2\text{nOH}^{-} \tag{8}\]  
An ongoing increase in OH can be the result of silicate particle polymerization, which is formed during the resumed chemical activity of C\({}_{3}\)S at the end of the induction period [8]. The initial hydrolysis is considered to be primarily due to the leaching of excess calcium oxide from the C\({}_{3}\)S structure (3). The end of the chemical induction period can be determined both by the crystallization of CH (Ca(OH)\({}_{2}\), see (7), and by the formation of a needle-like C-S-H gel (calcium hydrosilicate) from C\({}_{2}\)S. The main reaction that occurs during the growth of the needle C-S-H can be the polymerization of monosilicate ions in C\({}_{3}\)S for the purpose of desilylation (8). The crystallization of the two products is clearly interdependent. It is possible that the growth of CH removes calcium not only from the solution, but also from C\({}_{2}\)S, thereby contributing to the polymerization of silica. The second most important substance in the reagent is C\({}_{4}\)AF. When added to an aqueous medium, the reaction proceeds, and calcium hydroferitre is formed [8]:  
\[4\text{CaO}\cdot\text{Al}_{2}\text{O}_{3}\cdot\text{Fe}_{2}\text{O}_{3}+ \text{m}\text{H}_{2}\text{O}=3\text{CaO}\cdot\text{Al}_{2}\text{O}_{3}\cdot 6\text{H}_{2}\text{O}+\text{ CaO}\cdot\text{Fe}_{2}\text{O}_{3}\cdot \text{nH}_{2}\text{O} \tag{9}\]  
The hydrolysis of C\({}_{4}\)AF can be described by the following equation:  
Figure 5:0  
where FH3 denotes a hydrated amorphous Fe-containing gel. For the third substance, C\({}_{3}\)A, which is a reagent, the interaction in an aqueous medium can be described by the equation with the formation of calcium aluminate hydrates [8]:  
Figure 5:1  
3 CaO\(\cdot\text{Al}_{2}\text{O}_{3}\cdot\text{6H}_{2}\text{O}\)  
When C\({}_{3}\)A is dissolved in water, it results in ions in solution according to the following equation:  
Figure 5:2  
3 Ca\({}^{2+}\) + 2 Al3 + 12 OH Figure 5:3  
When hydroxyl-AFm precipitates, the equation takes the following form:  
Figure 5:4  
Since charged particles of the dispersed phase are present in the saponite suspension, the addition of calcium aluminum silicate inorganic coagulant is effective. The use of coagulants with strong pH shift to base medium will help ensure the production of large aggregates with a high deposition rate and large flakes. The destruction of the double electron layer in the saponite particle is achieved, due to the chemical activity of the inorganic coagulant. The sample of mineral inorganic coagulant that was obtained was added to saponite-containing water to detect the coagulating ability of the reagent. The initial content of suspended clay substances in the recycled water at the beginning of the experiment was 6320 mg/dm\({}^{3}\). After 40 min of settling time, the spectrometric analysis showed that the turbidity of the clarified water was 278 mg/dm\({}^{3}\); thus, the recycled water was purified to a level of 95% (Figure 6). The study of a calcium-aluminum-silicate reagent effect on clay minerals was carried out using a TESCAN Vega electron scanning microscope with a field emission cathode at an accelerating voltage of 20 kV in secondary electron detection mode [25]. The sample of the condensed sediment was dried at room temperature and attached to the holder with conductive carbon tape (Figure 7). Figure 5:5 Verification of the coagulation properties of the obtained calcium aluminosilicate reagent sample: (a) deposition within 15 min, (b) deposition within 30 min, (c) comparison of pure distilled and clarified water after 45 min of settling time. The morphology of the aggregates shown in Figure 7A is specific to mixed-layer materials, which are characterized by non-pronounced morphological features.