CUBA: Zeolite, Mineral of a Thousand Uses

  • by Patricia Grogg* - Tierramérica (havana)
  • Saturday, January 30, 2010
  • Inter Press Service

Cuban expert Martha Velásquez believes this non-metallic mineral of volcanic origins will play an essential role in sustainable development. Its various uses range from filtering out toxic gases to recovery and improvement of soils, livestock nutrition and as an additive to cement to create lightweight concrete for construction.

Zeolite's wide range of uses are due to its potential as an exchanger of ions, its capacity for reversible adsorption (the process through which a solid is used to eliminate a water soluble substance), and its function as a natural molecular sieve, which means it can be used to clean up aggressive toxic substances.

It is also capable of ionic exchange in heavy metals, like lead, nickel, iron and cobalt, and of purifying potable and wastewater for appropriate discharge, Velásquez, an expert with the government's Research Centre for the Mining-Metallurgic Industry, told Tierramérica.

Because of its low cost and great versatility, zeolite also plays an important role in agriculture. It can be used to improve soils, boost the effects of chemical and organic fertilisers alike, and as a component of substratum for the development of different crops.

For livestock, it is used as a food additive for several types of animals and in bedding, which results in a fertiliser rich in ammonia and other high-quality substances for farming, said Velásquez.

According to official sources, 70 percent of Cuba's cultivated area suffers from erosion, high salinity or acidity. However, the use of zeolite remains limited in the farming sector, which has yet to recover from the economic crisis of the 1990s triggered by the collapse of the Soviet Union and the East European socialist bloc, Cuba's main aid and trade partners.

The wave of economic recession also interrupted the programmes for mining and development of zeolite, which had been gathering force in the 1980s.

The lack of transport and capital, in addition to other obstacles created by the crisis, put the brakes on zeolite, which had been on its way to widespread use, especially in agriculture.

Velásquez said the current policy for reactivating the farming sector will lead to an expansion of zeolite use. 'We are studying the issue of transport and looking for the most economical options,' she said.

Other experts said that boosting domestic consumption is the priority at the moment.

'We want to employ our resources in the country, but confidence in Cuban zeolite and the technology we've created is needed. Unfortunately, many entrepreneurs are distrustful of local products,' said an official interviewed by the Cuban news media.

As part of the recovery plans, the government is investing in three zeolite plants currently in operation. The goal is to prepare them for a future increase in demand. Improvements are also planned for about a dozen zeolite deposits around the country.

In 2008, Cuba exported 600 tonnes of zeolite. The total in 2009 reached 4,490 tonnes. Among the buyers is Brazil, where among other uses, the mineral goes toward replacing highly polluting sodium tripolyphosphates in the manufacturing of detergents.

There is a high demand for zeolite in the European Union, United States, Canada and some Latin American countries. Prestigious institutions in Brazil and Japan have great faith in the high quality of Cuba's natural deposits, said Velásquez.

'It would be ideal to process the mineral in Cuba and then sell it with greater added value, but we lack financing,' said another expert.

According to studies, there are more than 50 types of zeolitic soils. Clinoptilotite possesses properties best-suited for adsorption filtration and sequestering cations (positively charged ions). Zeolites - 'boiling stones' in Greek - have a cage-like structure formed by tetrahedrons, united by oxygen atoms.

The mineral is most typically found in areas where there were prehistoric volcanoes. The United States, Australia, Turkey, Japan and China, as well as several countries of Africa, are among the leading producers of zeolite, although it is believed the mineral can be found on all continents.

According to data from Cuba's National Office of Mining Resources, there are deposits of zeolite distributed among almost all of the island's provinces.

(*This story was originally published by Latin American newspapers that are part of the Tierramérica network. Tierramérica is a specialised news service produced by IPS with the backing of the United Nations Development Programme, United Nations Environment Programme and the World Bank.)

© Inter Press Service (2010) — All Rights ReservedOriginal source: Inter Press Service

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