Production and successful application of zeolite materials in Vietnam

With breakthrough technology, experts from Hanoi University of Technology have turned natural clay minerals in Vietnam into high-value zeolite materials in cultivation, animal husbandry, chemical industry, and environmental protection.

Prof. Dr. Hoang Trong Yem (left) and Dr. Ta Ngoc Don stand in front of the display cabinet of zeolite products manufactured by Hanoi University of Technology.

Recently, two zeolite factories in Quang Binh and Can Tho have been built and put into operation with a capacity of 3,000 tons / year, in the form of technology transfer from the Polytechnic University to the locality. These are the first factories in Vietnam to produce zeolite on an industrial scale, serving aquaculture.

Success from the spirit of dare to think, dare to do

According to Dr. Ta Ngoc Don, chairman of the project and deputy head of the Department of Chemical Technology, zeolite is a porous material, in the form of powder or pellets, settling to the bottom of the pond. There, it acts to adsorb metal ions, ammonium, H2S, NO2, NO, and toxic organic substances, thus cleaning up the aquaculture environment. When dredging ponds and lagoons, zeolites with toxic pores will be recycled for future fertilizer.

The aforementioned Zeolite is produced from the available clay in Vietnam. The main material is kaolin, a clay mineral that exists in many localities with large reserves, which can be exploited and used for hundreds of years. Other types of lightning resistance can also be used as additives in zeolite production.

Prof. Dr. Hoang Trong Yem is the person who gave the first ideas of turning Vietnamese natural clay minerals into high value materials. He said that the production technology of this zeolite is not only new in Vietnam but also to the whole world. No country has converted unburnt kaolin into zeolite. But with the thought of thinking, daring to do, overcoming the skepticism of experts and taking risks, the team went in this direction. Their motto is that if they try to find, they will see what the world has not studied.

After a complete failure with 500 samples, the team eventually made zeolite on September 30, 1999, more than a year after the construction began. The structure of unburnt kaolin is broken down with chemicals, then rearranged into zeolite. Simply put, like Dr Don, I can liken kaolin material as a block of bricks that are closely linked. The trick is to make these bricks separate and arrange them into a block with holes.

This is the new invention in cheap zeolite production, meeting the huge demand today in Vietnam. As for the traditional method of calcining kaolin, the material structure is not completely broken, so the performance is not high.

In Vietnam, there are also some units that research and produce this material from clean chemicals. However, it is difficult to apply on a large scale because of the high cost. In contrast, due to the use of clay to make zeolites, the cost of domestic products is only 1/10 of zeolite from clean chemicals and about 1/2 natural zeolite. It is known that the price of natural zeolite imported from Thailand and Indonesia used in fisheries is 4,000-4,200 VND / kg while the price of zeolite synthesized from natural clay minerals according to Hanoi University of Technology is less than half.

Wide application potential

Zeolite materials used in environmental protection.

Dr Don said that zeolite used in fisheries is just one of six applications of this material that the research team is implementing. Taking advantage of adsorption properties, the team created zeolite-containing fertilizers. Zeolite will slowly release nutrients in the fertilizer into the soil, help to save fertilizer, increase fertility (due to the porous material, so it will porous soil), keep the moisture and regulate the soil pH (in Vietnam slightly acidic soil while zeolite is alkaline.

Fertilizer containing zeolite has been applied in the summer-autumn rice crop in 2005 over 3,000m2 in three districts of Thanh Hoa province. The results show that this type of fertilizer benefits 300,000-600,000 / ha compared to the control. The group has completed the technology and is cooperating to build the first project of building a NPK fertilizer containing zeolite in Vietnam with a capacity of 15,000 tons / year.

In the livestock sector, the group is trying to test zeolite preparations as feed additives for pigs and chickens. When mixed into food, the composition will adsorb toxins in the animal body, increase resistance to disease, stimulate digestion and growth. It is known that zeolite is not toxic to humans and pets.

Zeolite is also used to separate heavy metal ions, ammonium, toxic organic compounds in wastewater and domestic water. The product has been tested to clean Ho Van water and give good results. In addition, this material is also used in the manufacture of absolute alcohol (due to the selective water separation properties of zeolite), petrochemical (due to adsorption and catalytic properties), pharmaceutical chemicals and plant protection chemicals. .

Although there have been 4 inventions and utility solutions granted, the research team has not stopped. Their intention is to create larger-sized porous materials to absorb colorants in dyed sewage and large molecular organic compounds. Currently the current particles are 1,000-5,000 nm in size, so the team also has the idea of ​​reducing the particle size to below 100nm to create nano-zeolite materials to increase the applicability of this material in the future.

Zeolite used in aquaculture

Dr Don and his colleagues examined rice after using NPK containing zeolite

Use zeolite for shrimp farming on sand

6-7 groups of hundreds of people, including students, participated in this study.