Abstract: A diatomaceous earth product with low crystalline silica content after at least one calcination step of between about 927° C. (1700° F.) and about 1149° C. (2100° F.) is disclosed. The product comprises natural diatomaceous earth and at least one binding agent comprising potassium silicate. Further the product comprises no more than about 4.0 wt % of crystalline silica and has a permeability in the range of about 0.3 darcy to greater than about 20 darcy. A process for making such diatomaceous earth product with a low crystalline silica content is disclosed. Moreover, a diatomaceous earth filter aid comprising such a diatomaceous earth product is disclosed.

Abstract: A method of producing a range of diatomaceous earth filter aids having selectable permeabilities and less than about 1 percent by weight total crystalline silica. The method includes milling diatomaceous earth ore to a size range of between about 100 micrometers and about 1400 micrometers; calcining the milled diatomaceous earth in a calciner; and milling the calcined diatomaceous earth in an adjustable milling and classification system to produce diatomaceous earth filter aids. Systems to implement such methods and compositions produced by such methods are also described.

Abstract: A method of producing a range of diatomaceous earth blended filter aids having selectable permeabilities and less than about 1 percent by weight total of crystalline silica and less than about 0.1% by weight total of respirable crystalline silica. The method includes milling diatomaceous earth ore to a size range of between about 100 micrometers and about 1400 micrometers; calcining the milled diatomaceous earth in a calciner; milling the calcined diatomaceous earth in an adjustable milling and classification system to produce diatomaceous earth filter aids, and blending the diatomaceous earth with expanded perlite to form a low bulk density and low solubility filter aid.

Abstract: A method of producing a range of diatomaceous earth filter aids having selectable permeabilities and less than about 1 percent by weight total crystalline silica. The method includes milling diatomaceous earth ore to a size range of between about 100 micrometers and about 1400 micrometers; calcining the milled diatomaceous earth in a calciner; and milling the calcined diatomaceous earth in an adjustable milling and classification system to produce diatomaceous earth filter aids. Systems to implement such methods and compositions produced by such methods are also described.

Abstract: A method of removing arsenic and heavy metals from water using metal salt hydroxidegels is provided. The arsenic present in water is adsorbed onto the hydroxide-gels which can effectively be filtered through a diatomaceous earth (DE) filtration bed. The combination of DE mixed hydroxide-gels is also effective in removing arsenic from water and heavy metals from water.