Vermiculite

About: Vermiculite is a research topic. Over the lifetime, 2320 publications have been published within this topic receiving 37142 citations.

Inorganic modification of Palabora vermiculite

Abstract: Conventional processes for the manufacture of exfoliated natural vermiculite employ temperatures exceeding 800 °C and the onset temperature is above 450 °C. In many applications, notably fire retardants, it is desirable that exfoliation of vermiculite should occur at temperatures in the range of 200 °C to 350 °C. For this purpose, South African Palabora vermiculite was modified by ion exchange with ammonium and selected alkali metal and alkaline earth metal ions. These experiments were performed at room temperature using an orbital shaker for 15 days. Another set of experiments was performed by immersing vermiculite in saturated sodium chloride solution for periods up to six months. At the end of every month, sodium-exchanged vermiculite samples were taken for analysis. The thermal expansion and degradation of modified vermiculites were studied using thermo-mechanical analysis (TMA) and thermogravimetric analysis (TGA) respectively. Interlayer composition was studied using cation exchange with ammonium acetate. The leached cations were quantitatively determined using inductively coupled plasma optical emission spectroscopy (ICP-OES). Scanning electron microscopy (SEM) was applied to study the

Soil mixture special for cultivating Clivia miniata

Abstract: The invention provides a soil mixture special for cultivating Clivia miniata. The soil mixture comprises, by weight, 230-250 parts of garden soil, 10-15 parts of matured cake manure, 0.3-0.5 part of ammonium dihydrogen phosphate, 0.1-0.2 part of potassium sulfate, 4-6 parts of mountain clay, 3-5 parts of aminosuccinic acid and 1-2 parts of vermiculite. The soil mixture meets the growth need of vermiculite for nutrition, and a slightly acidic growth environment is provided for Clivia miniata; experiments show that leaves of potted plants of Clivia miniata grown with the soil mixture are thick green, flower brightness is increased, and a flowering period is prolonged by more than 18%.

Parent Materials and Climate Control Secondary Mineral Distributions in Soils of Kalimantan, Indonesia

Abstract: Secondary mineral distributions in soils from Kalimantan, Indonesia, were investigated to examine the effects of the parent materials and climate at different elevations on the distributions. B horizon soils were sampled at 60 sites on gentle slopes at different elevations (20–1700 m altitude). Each major parent material (sedimentary, felsic, and intermediate to mafic) was represented at different elevations. The soil samples were classified from their total elemental compositions using cluster analysis. Secondary minerals were measured by X-ray diffraction and selective extractions. The samples were divided into ferric (high Fe contents), K&Mg (high K, Mg, and Si), and silicic (high Si) groups. The ferric soils were derived from mafic parent materials, whereas the others were derived from felsic or sedimentary parent materials. The K&Mg soils had higher total base contents (suggesting primary minerals) and were less weathered than the silicic soils. Secondary minerals in the ferric soils were characterized by high contents of Fe oxides and gibbsite. The K&Mg and silicic soils had similar secondary mineral (kaolinite and vermiculite) contents, but more mica was found in the former. Only the silicic group soils had secondary mineral contents that changed as the elevation changed (the kaolinite content increased and the vermiculite and poorly crystalline Al and Fe contents decreased as the elevation decreased). Higher temperatures at lower elevations may cause minerals to be altered more. Secondary mineral distributions were primarily controlled by the parent material (mafic or felsic/sedimentary) and, secondarily by the climate, which varied with elevation.