Liquid alkali-free chloride-free accelerating agent as well as methods for preparing and using same

The invention discloses a liquid alkali-free chloride-free accelerating agent and methods for preparing and using the same. Raw materials for preparing the accelerating agent include one or a plurality of the following components of aluminum sulfate, magnesium sulfate, hydramine, an early strength agent, a synergist and water. The aluminum sulfate is the purchasable industrial-grade aluminum sulfate hydrate Al2(SO4)3.18H2O and has the solid content of 51%-52%. The magnesium sulfate is MgSO4.7H2O with the solid content of 48%-49%. The hydramine is one or a plurality of mono ethanol amine, diethanolamine, triethanolamine or isopropoxide. The early strength agent is one or a plurality of calcium sulfate, calcium formate or calcium nitrite. The synergist is magnesium fluosilicate and/or magnesium fluoride. The liquid alkali-free chloride-free accelerating agent provided by the invention has the characteristics of good adaptability, low price, low mixing amount, good performance, good stability and the like; and moreover, the liquid alkali-free chloride-free accelerating agent is added into the concrete to be used as sprayed concrete, has the characteristics of low resilience, small dust pollution and the like and can satisfy the requirements of the 'JC477-2005 sprayed concrete accelerating agent' standard.