River sand and quartz sand are essential aggregates for dry-mixed mortar products and play an important role in the formulation system. Its roundness, particle size, water, and mud content directly affect cement mortar’s bond hardness, compressive strength, and construction performance.

For dry-mixed mortar products, typically, there are rigorous quality and performance requirements of the aggregate. The strength and impurities of the aggregate depend on the nature of the parent rock. It is primarily volcanic rock, metamorphic rock, and granite if the parent rock is in a severely weathered area, so the aggregate is darker in color and more complex in composition; If the parent rock is in a quartzite zone, the aggregate is mostly quartz sand with a lighter color. Quartz sand with better roundness is mainly distributed in rivers’ middle and lower reaches. It contains fewer impurities after long-distance transportation and scouring by river water. This type of river sand aggregate is primarily used in dry-mixed mortar. After panning and excavation, it must be washed, dried, and screened to become river sand aggregates of different grades. Dry river sand with good roundness, shallow texture, fewer impurities, and less mud is the first choice for preparing dry-mixed mortar products.   

Quartz sand is a siliceous raw material that refers to natural mineral raw materials with high SiO2 content, usually including quartz sand, quartzite, vein quartz, and powder quartz. The chemical composition is SiO2, glass luster, and the fracture is greasy luster. Shell-shaped fracture, hardness 7, density usually 2.65~2.66g/cm3o different colors. Colorless and transparent, called crystal, and milky white, called milk quartz. According to its crystallization habit, the trigonal crystal system is low-temperature quartz, also known as α-quartz, and the hexagonal crystal system is high-temperature quartz, also known as β-quartz.

Quartz sand is a technical term for mineral products, and it generally refers to various sands in which the quartz component is dominant, such as sea sand, river sand, and lake sand. According to the origin of geology, they are divided into alluvial sand, slope sand, and residual sand. In industrial applications, sand with a specific particle size processed from quartz sandstone, quartzite, and vein quartz is also called quartz sand. Quartz sandstone is a consolidated sandy rock. The content of quartz and siliceous clasts is generally above 95%, the accessory minerals are mostly feldspar, mica, and clay minerals, and the content of heavy minerals is minimal. Common heavy minerals include tourmaline, rutile, magnetite, and ilmenite; the cement is generally siliceous. Silica-cemented quartz sandstone is also called siliceous sandstone, and the cement mainly has opal. In addition, there are calcareous, iron, and glauconite quartz sandstones. It is rare even though dolomitic cemented quartz sandstone exists. Quartzite is a metamorphic rock formed by the metamorphism of quartz sandstone or other siliceous stones. Vein quartz is a magmatic-hydrothermal vein associated with granite. Its mineral composition is almost entirely quartz. Powder quartz is a natural mineral with excellent particles and high silica content.