The invention discloses lightweight sandstone. The lightweight sandstone is characterized by comprising the following components in percentage by weight: 70-90% of silica sand, 8-21% of organic
adhesive and 6-16% of inorganic
flame-retardant
powder. A production method of the lightweight sandstone is further provided, and comprises the following steps: (1) weighing the components, mixing the weighed inorganic
flame-retardant
powder and the weighed organic
adhesive in a container, and stirring the weighed inorganic
flame-retardant
powder and the weighed organic
adhesive evenly; (2) then addinga catalyst and a curing agent for even stirring; (3) after the silica sand is weighed and is ground to be 30-60 meshes, adding ground silica sand into a mixture in the step (1), and conducting stirring for 10-20 minutes; (4) pouring an obtained mixture into a mould, and conducting compaction and
smoothing; and (5) after the mould is placed in a
drying tunnel for
drying, conducting demoulding. No waste or harmful gas is generated in the production process, no
pollution is generated, and waste is turned into wealth; the average
sound reduction index of a lightweight sandstone slab is above 30 dB, a sound absorption and reduction coefficient is larger than 0.7, both the average
sound reduction index and the sound absorption and reduction coefficient exceed the
national standard, and the mechanical performance is good, so that the lightweight sandstone slab is an ideal outdoor acoustic sound absorption material; and the fireproof performance reaches an A grade.