Quality Evaluation And Performance Improving Of The Clay From The East Pacific

The sea clay has been paid attention to by people since in1930s, for the first time, foreign scholars discovered that the clay minerals, such as illite, montmorillonite and kaolinite, in the sediments from the Pacific are endowed with crystal character. From then on, the research atmosphere on the sea clay sediments has been activated, and while in 1960s, correlative works on the type, distribution, cause of formation, and etc of the sea clay minerals, appeared one after the other. Nevertheless, our country began to study on it in later period of 1970s, and in the middle stage of 1980s, investigations on the ocean clay minerals, most of which is from the Pacific, started as well. The sea clay was mainly used for reflecting the change of the geologic environments, such as ancient geography, ancient climate, and ancient environment, due to it possessing minute grain, out-of-order structure and variable composition, so the research passion has been gone down to now. Investigation of the clay from the east Pacific, which was made to reflect the change of the geologic environments, has already been exceedingly mature, especially the research on geochemistry characteristics of the REEs in sediments and its indication meaning for the clay minerals. However, study on the application of the ocean clay has not been reported yet. The resource potentiality of the clay and ooze in the world ocean is so tremendous, the amount of which is 2.1×10~7km~3 and 3.1×10~7km~3 respectively according to the reported data, that the application and development of these resources will have significant meanings, in particular as the reserve resources. First of all, quality evaluation of the clay from the east Pacific was done in this paper. By test and analysis of the clay sediments, including mineral composition, chemical component, crystal structure, physical-chemistry properties, and etc, it demonstrates that the sea clay is provided with the characteristics of minute granule, out-of-order structure, abundant organic substances and REEs. Simultaneously, it shows that the sea clay will possess more highly reaction activity and more extensive, better application future. However, as the content of iron, manganese oxides in the ocean clay sediments is so much, which induced low whiteness of the samples, bleaching test on the ocean clay was carried out by adopting the chemical reduction method. Besides, surface modification of the clay was conducted too, which provides the experiment evidences, lays solid foundations for it turning into functional filler of other applications. The paper falls into six sections, including introduction, type of sediments in the investigated area of China Ocean, quality evaluation of the ocean clay sediments, purification and bleaching test on the ocean clay, surface modification of the ocean clay and conclusion section. The chief content and interrelated conclusion in this paper is come to as follows. In the majority of the surface layer sediments of China Ocean investigated area, the east Pacific, the main constituent is clay mineral whose content is much more, except that several samples are carbonate sediments. Their main mineral constituent is irregular I/S mixed layer, with a small quantity of kaolinite and chlorite. Feldspars and quartz were also detected. The quantity of organic substances, most of which is more than 1%, with the minority reached 10%, is greater while comparing with the homogeneous clay in earths surface. Chemical composition of the representative clay sediments shows that the ocean clay is abundant in REEs, and iron, manganese oxides content is larger which results in the low whiteness of the samples. As a result of the physical-chemistry properties test of the ocean clay, the granule is fine, the crystallization degree is bad, and its microcosmical conformation is mainly of floccule and sandwich. Thermal stability of the ocean clay is excellent, while CEC is small. In order to increase the whiteness of the sea clay and widen its application field, iron and manganese removal research on the specimen was performed by using acid dissolving hydrogen reduction method just after a great number of experiment methods were tried. Better bleaching result was achieved, with iron removal ratio being more than 98.5% (Because of the mass demand for the sample, manganese oxides content of the selected specimen is very small, and existing of the great quantity of iron oxides is the main reason decreasing its whiteness). Also,the ratio surface area of the sample increases, and the dispersing ability in organic solvent becomes better while increasing its whiteness. The whiteness will continuously increase when to calcine, and the whiteness will increase about 49% at best. But the partial structure of the clay mineral will collapse, and its activity will decrease. Therefore, the specimen without calcinations, before and after acid treatment was chose to be modified by different techniques. The purified sample was modified by mechanical chemistry surface modification method. After a series of modification conditions, modifiers, and etc were sieved, we draw a conclusion that the silane coupling agent and alminate coupling agent are the best modifiers. The water-absorbing ratio of the modified sample decreases obviously, and its dispersing ability in organic medium improves evidently. X-ray diffraction analysis indicates that the out-of-order degree of the clay mineral increases after modification, and the space between layers increase too, which demonstrates that organic modifier takes up partly interspaces between the layers of the clay, improving the water absorbing ability between the layers, thus, in favour of the sample dispersing in organic medium easier. In the same way, that the ratio surface area of the modified sample decreases is the result of the modifier molecules entering the structure of the clay, and stuffing up partial pores while grinding. In combination with FTIR spectroscopy, X-ray diffraction, thermoanalytical method (DTA) and SEM analysis, educes the conclusion that the bonding mode between the ocean clay and modifiers is mainly the chemical bonding and coverage, this bonding mode indicates that the modified sample will perform an effectively reinforcing function as filler for macromolecule materials. However, without chemical bleaching, the sample can only be the reinforcing filler for fuscous macromolecule materials that are not affected by iron, manganese oxides. So, the application area is limited. Wet modification was the process of organic activation, during which the washed, filtrated cake of the acid treated sample was made into slurry immediately, and modified by adding into modifiers in the course of stirring. It reveals that the modified result is the best when the slurry thickness was 30%, reaction time was 40 minutes, and the added silane quantity was 3.0%. In combination with ratio...