Increasing expansion of China's coal mine production leads to the increased storage pressure in current coal silos. Most of these coals are stored in open-air coal pile. Therefore, those coal piles have caused a series of environmental pollution problems, which includes endangering workers' health and aggravating air pollution in the surrounding natural environment. Therefore, it is urgent to study and prevent the dust flying problem of coal pile. This paper, based on a single chemical dust suppressant, optimizes a new type of composite binder. This composite binder has advantages of dust suppression effect, relatively simple preparation process and the environmentally friendly agent. This paper is mainly divided into two parts: the study on the influencing factors of dust wetting and the development and application of related spraying systems. Through the energy spectrum analysis of scanning electron microscope and reverse osmosis method, it explores the dust wetting and suppression characteristics of the composite binder with different physical and chemical properties. The optimal application range of the composite binder are obtained. Finally, an automatic spraying system for dust suppression is designed. The composite binder developed in this paper is applied in the open-air coal yard and the results show that the composite binder studied in this paper has a good effect of dust suppression. (C) 2020 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.