## 3 Result and Discussion
### Cost of Industrial Solid Waste-Based Composite Powder Explosion Inhibitors  
The costs of the industrial solid waste-based composite powder explosion inhibitors under different preparation methods were calculated and compared with conventional powder inhibitors over economy and efficiency. Table 5 gives the costs of consumables,  
Figure 8: Explosion suppression characteristic data of coal dust by industrial solid waste based composite powder explosion inhibitors. namely, the price paid for purchasing the laboratory chemicals, used for preparing the industrial solid waste-based composite powder explosion inhibitors, without considering the expenses related to the material analysis and the experimental apparatuses. In addition, Table 5 gives the average amount of consumables used for preparing a kilogram of the industrial solid waste-based composite powder explosion inhibitors using the WCSC and DCBM methods. Table 5 gives the average amount of consumables used for modifying each kilogram of industrial solid waste. The calculations show that it costs an average of RMB11.6 to modify a kilogram of industrial solid waste. In the case of the WCSC method, the consumables used include modified industrial solid waste, carrier, ethanol and distilled water. In the case of the DCBM method, only a modified industrial solid waste and a carrier are needed. Figure 9 gives the costs of each kilogram of the industrial solid waste-based composite powder explosion inhibitors. As calculated, when the WCSC method is used, the average cost is RMB14.4/kg for the industrial solid waste-based NaHCO\({}_{3}\) composite powder explosion inhibitor and RMB18.1/kg for the industrial solid waste-based KH\({}_{2}\)PO\({}_{4}\) composite powder explosion inhibitor; when the DCBM method is used, the average cost is RMB11.8/kg for the industrial solid waste-based Al(OH)\({}_{3}\) composite powder explosion inhibitor and RMB14.9/kg for the industrial solid waste-based composite powder explosion inhibitor. By comparison, \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Consumable** & **Average Consumption** & **Unit Price (RMB)** & **Mass or Volume** \\ \hline \multirow{4}{*}{Average consumption of 1 kg of modified solid waste} & Absolute ethanol & & & \\  & (C\({}_{2}\)H\({}_{\text{G}}\)O) & 0.3 L & & 500 mL \\  & Distilled water & 4 L & & 10 & 40 L \\  & Ammonia water & 0.4 L & & 7 & 500 mL \\  & Hydrochloric acid & 0.1 L & & 10 & 500 mL \\ \hline The average amount of & C\({}_{2}\)H\({}_{\text{G}}\)O & 0.3 L & & 5 & 500 mL \\   consumables used in the & Distilled water & 6 L & & 10 & 40 L \\   preparation of 1 kg of industrial & NaHCO\({}_{3}\) & 0.5 kg & & 6 & 500 g \\   solid waste based composite & KH\({}_{2}\)PO\({}_{4}\) & 0.5 kg & & 10 & 500 g \\   powder explosion inhibitors & Al(OH)\({}_{3}\) & 0.5 kg & & 8 & 500 g \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Average consumption of 1 kg of modified solid waste. Figure 9: Cost of different types of industrial solid waste based composite powderexplosion inhibitors. while WCSC method is more costly than the DCBM method, as it consumes more chemical reagents, its load ratio works more effectively on coal dust explosion. Hence, the industrial solid waste-based composite powder explosion inhibitors prepared using the WCSC method is more efficient in suppressing coal dust explosion than those prepared using the DCBM method. In the ZYBG-12Y mine intrinsically safe pipe explosion suppressing system (China Coal Technology & Engineering Group, Chongqing province), one of the most popular coal dust explosion units for industrial production in China, ABC dry powder is used as the powder suppressor. Under the Chinese national standard, all ABC powder inhibitors must contain a minimum of 50% (NH4)H2 PO4[29]. Studies have demonstrated that (NH4)H2 PO4 has a better explosion suppression performance than ABC dry powder [30]. Some researchers [21; 31] investigated the coal dust explosion suppression property of (NH4)H2 PO4.