Natural carbonates have an enormous importance in the world's economy due to their numerous applications. According to their different uses, such as calcium carbonate in the paper and paint industries, the final products have rigorous quality specifications which are currently difficult to meet for local producers in Brazil. Therefore, large quantities of high-grade carbonates are transported long distances inside the country to supply the different industrial plants. In southern Brazil, carbonate ores are used mainly for agricultural purposes. In Cacapava do Sul, the selectively mined ore is currently hand-picked at low throughputs to produce high-grade (white) carbonate. This paper present applied research work to improve the product quality and gives an overview of the market situation for the regional producers. The aim of the work is threefold: - to characterize the raw ore and determine the potential for production of the required quality and quantity for the Brazilian market; - to develop an industrial process incorporating optical sorting and comminution (high intensity magnetic separation was tested too); - to control the quality of the products by application tests, including the measurement of brightness. (c) 2005 Elsevier Ltd. All rights reserved.