Bleaching clay plays an important role in refining, bleaching, and decolorizing edible oil. It is also used for removal of phospholipids, sulfuric acid, sludge, sulfonic acid, free fatty acids, and traces of metal in oils. Besides these applications, it is used in effluent treatment plants and as an ingredient in cosmetic products.
Raw materials used in formulating bleaching clay include fuller’s earth, bentonite, attapulgite clay, sulfuric acid, hydrochloric acid, and hydrated sodium calcium aluminosilicates. The process of manufacturing bleaching clay starts from sourcing of fuller’s earth, bentonite, or attapulgite clay. This clay is later processed and activated using chemicals in the required specifications to enhance its bleaching and refining quality.
Raw material suppliers present in the value chain include mining companies such as Balcones Minerals Corporation, Bennett Mineral Company, Engelhard Corporation, and Bajaj Earth Private Limited Corp. The global production of bentonite according to the United States Geological Survey (USGS) was approximately 16 million tons in 2015. The U.S. and China are the world largest bentonite producers and accounted for 50% to 60% of the overall supply in 2015.
Crude oil refining includes degumming, neutralization, bleaching, deodorization, and further refining. Bleaching clay is widely used in the edible oil and fat industry in the decolorizing and refining process. Crude oil is bleached with natural or acid-activated clay minerals to absorb coloring components and to decompose hydro-peroxides. Bleaching clay also helps in removal of contaminants such as oxidation products, phosphatides, pigments, and metals & soaps.
During the 50th and 60th century, bleaching earth was used in large proportions in the mineral oil industry for refining & bleaching paraffin, wax, insulating oils, rolling oils, waste oils, lubricants, and greases. However, due to high costs and environmental concerns regarding the acidulation and bleaching process that used bleaching clay is replaced by hydrogenation processes such as hydro-treating & hydro-finishing.
During the bleaching process, use of bleaching clay removes color and absorbs phosphatides, metal, residual gum, and oxidized products from the oil. During this process, the bleaching earth also absorbs a significant amount of oil; thus, it can cause oil loss to the manufacturer as the bleaching earth has an oil retention property of up to 70% of the bleaching earth’s weight. Almost 30% to 40% oil is spent in bleaching earth. This property can cause significant loss of revenue to the company as the quantity of oil produced would be low.
The use of bleaching clay in Asia Pacific and America is projected to grow at the highest CAGR on account of the increasing oilseed crop yield in these regions. The increasing demand for refined vegetable oil used in food applications is expected to increase the demand for bleaching earth over the forecast period.
In-depth report on global bleaching clay market by Grand View Research: