Application of Natural Complex Raw Material in Container Glass Production

Abstract

It is shown that high-silica sedimentary rock can be used as a natural raw material in energy-efficient production of colored glass containers. The phosphorus oxide present in the rock influences the viscosity and crystallization properties of the synthesized glasses. The physical and chemical properties of the glass obtained correspond to the operating properties of container glass based on conventional raw material.Many large manufacturing plants, including glass plants, face shortages of raw material due to the exhaustion of natural conditioned raw materials, inadequacy of equipment at operating mineral enrichment plants, remoteness of raw material bases and impossibility of developing new deposits. One solution to this problem is to find sources of alternative raw materials and develop technology for using them in manufacturing. Specifically, silica-containing rocks which are common in the Russian Federation can be used in a number of cases to replace quartz sand [1,2]. The adoption of this raw material in glassmaking makes it possible to reduce production costs by lowering the cost of glass batch and sometimes by intensifying glass production.In the present work the possibility and prospects for replacing in glass production the conventional by unconventional raw materials are demonstrated for the example of high-silica rock (HSR) of sedimentary origin.The chemical composition of rock consists mainly of silica and calcium-containing compounds (Table 1), which is a prerequisite for partial or complete replacement of quartz sand and calcium-containing raw material (dolomite, chalk, limestone) by HSR in the recipe for glass batch.The oxides of alkali elements, magnesium and aluminum, which are present in small quantities in rock, are harmless impurities in glassmaking and do not limit the glassmaking process, but they must be taken into account in figuring the batch. Iron oxide is a strong colorant and at the content indicated precludes the use of rock for obtaining colorless glass. However, in the manufacture of colored glass, for example, container glass, its presence in the raw material is desirable from the standpoint of conservation of additives which are introduced in order to obtain a prescribed color tone of the glass.The polymineral composition of rock is represented by the aggregate of dominating silica-containing phasesa-quartz, cristobalite and tridimite as well as calcium-containing phases such as gypsum (calcium sulfate dehydrate), calcite (calcium carbonate) and hydroxyapatite (apatite-like calcium hydrophosphate) (Fig. 1). Of the carbonate minerals magnesite and dolomite are possible in very small quantities. Alkaline aluminum silicates from the feldspar groupmicrocline and orthoclase -are found in small quantities. A halo at small angles 2q attests to the presence of an amorphous phase. A silica matrix with individual inclusions of