Round silica sand

The materials commonly used as proppants can be grouped into three main categories, listed in Table 10.25. The first proppant material used was rounded silica sand mined from glacial deposits. This material was initially selected owing to both its wide availability near production wells and its low cost, but since the early days several other industrial materials have been selected and used as proppants, and today we observe the increased use of synthetic materials, especially sintered and fused ceramics. The main impetus in focusing on ceramics was driven by the fact that ceramic materials offer suitable properties for use in modern deep wells today. 

Rounded silica sand (e.g., Arizona Sand, Badger Mining, Borden, Colorado Silica, Hepworth, Oglebay Norton, Uninim)... 

Wedron Silica Division of Fairmount Minerals, South Olive Street, Wedron, IL 60557, USA Telephone +1 (815) 433-2449 Fax+1(815) 433-9393 E-mail sales wedronsilica.eom URL http //www.wedronsilica.com/ Round silica sand... 

The particle shape of sands produced by crushing dense limestones tends to be angular and cubical. This is satisfactory from the viewpoint of the properties of the hardened mortar, but tends to produce a somewhat harsher and less workable fresh mortar than many naturally occurring silica sands, which generally have a more rounded shape. 

Figure 3. Tensile strength vs. sand type and bulk density. Key , Wedron 5010 silica sand, round grain, AFS 65, four screen, 1.5% 3.0 1 silicate and O, Lake Michigan silica sand, angular to subangular grain, AFS 45, two screen, 1.5% 3.32 1...

Abrasive blasting, both dry and wet processes, are effective on all substrates, but they require experienced mechanics to minimize damage to surfaces. Pressures used are usually between 20 and 110 Ib/in (140 and 760 bars), and working distances are from 3 to 12 in (7.6 to 30 cm). The abrasives are usually silica sand, but crushed slags and coal wastes are often used. The mesh sizes are very fine, either 0 or 00. Round particles are less abrasive and damaging than crushed grains. 

Zivanovic (1995) presented a description of clinkers made with silica fume, instead of quartz sand, as the primary silica component in the raw feed. The silica fume made up approximately 3.0 percent of the feed. Alite crystal size was reported to be from 50 to 200 pm and belite grains were said to be rounded and between 50 and 60 pm. No mention of belite nests was made. The cements made with silica fume or tuff and a particular marl, compared to other cements not made with these materials, did not require as much grinding and produced higher 28-day mortar strengths. 

Termite Bioassays. Multiple choice tests were conducted using wood blocks of birch, red oak, redwood and Alaska yellow cedar where blocks were decayed by P. chrysosporium for either 3,8, or 12 wk. Bioassays were conducted using rectangular Rubbermaid storage containers (14.5 cm X 8.5 cm X 4 cm) (Consolidated Plastics, Twinsburg, Ohio). Each container served as a replicate and was filled with 100 g of sand (Standard Sand and Silica Company, Davenport, FL) moistened with 20 ml of water. Each container had four 2-cm diameter holes, one hole on each side. A 14 ml (17 x 100 mm) polystyrene round-bottom Falcon test tube (Becton Dickinson, Franklin Lakes, NJ) was inserted into each hole and sealed in place using a glue gun. The position of treatment tubes was alternated between replicates to preclude any positional effects. Two hundred termites (190 workers 10 soldiers) were placed in the center of each container. The termites were able to move freely between the container and the tubes. 

---