Guar gum is needed for producing sufficient viscosity. Because less is required, costs are reduced. This would help explain its presence in so many things today. In addition to guar gum's effects on viscosity, its high ability to flow, or "deform", gives it very favorable rheological properties. It forms breakable gels when cross-linked with boron. It is used in various multi-phase formulations for hydraulic fracturing, in some as an emulsifier because it helps to prevent oil droplets from coalescing, and in others as a stabilizer to help prevent solid particles from settling and/or separating. Fracking entails the pumping of sand-laden fluids into
Hydrochloric acid acid is in the pickling of steel, to remove rust or iron oxide scale from iron or steel before subsequent processing, such as extrusion, rolling, galvanizing, and other techniques. Technical quality HCl at typically 18% concentration is the most commonly used pickling agent for the pickling of carbon steel grades. The spent acid has long been reused as iron(II) chloride (also known as ferrous chloride) solutions, but high heavy-metal levels in the pickling liquor have decreased this practice. The steel pickling industry has developed hydrochloric acid regeneration processes, such as the spray roaster or the fluidized bed HCl regeneration process,