English September 13, 2011- Gypsum is an important raw material for the construction industry. The demand for gypsum is very large, but our country still has to completely import this raw material. Meanwhile, the source of artificial gypsum that can be obtained from thermal power plants is being wasted. Around this issue, the Construction Newspaper had an interview with Mr. Le The Ngoc - Deputy Director of the Department of Building Materials (Ministry of Construction).
Could you please tell me the source of natural materials for gypsum production in our country?
There is very little natural gypsum in Vietnam (almost none). Gypsum is an important raw material for the construction industry, used for cement production, ceiling panels, wall panels, autoclaved aerated concrete production and many other industries. Meanwhile, Vietnam's demand for gypsum is increasing day by day. But currently, most gypsum in Vietnam still has to be imported. Gypsum used for cement production must be imported from Laos, Thailand, Malaysia and China. Gypsum for ceiling panels, wall panels are imported from Thailand and this gypsum is obtained from FDG. Gypsum is an indispensable ingredient for many key material production industries of the country such as cement, unburnt materials... These items are related to the field of real estate development, urban development. and industrial investment, affecting the stability of economic development strategies. Total dependence on imported raw materials can affect the stability of development strategies and cost a lot of foreign currency.
Could you please explain more about FDG gypsum and the process of forming FDG?
FDG gypsum (short for Flue-Gas Desulfurization Gypsum) is the product of the SO3 removal process in the chimneys of factories using high sulfur (S) coal such as coal-fired power plants, chemical factory... FDG gypsum is made by using ultra-fine limestone (SO3-absorbing liquid paste), according to a technological process. The gypsum produced in the form of crystals, exists in the form of a solid suspension (gypsum evenly dispersed in water). Gypsum is separated by water separation by equipment such as: cyclone water separator; centrifuge tank or vacuum filter cassette. The gypsum cake usually contains a certain amount of water, about 10%; The characteristics of this gypsum are high purity (high content of calcium sulfate dyhidrate) and slightly cloudy color.
The fineness and crystalline shape of gypsum are an extremely important indicator for use in the manufacture of gypsum board and may require harm reduction treatment steps. Gypsum quality is always a top concern. Issues that are always worth focusing on are the pH of the material; chlorine content; and in some cases fly ash and unburnt carbon mixed in.
How is this technology applied in the world? Currently, is there any facility in Vietnam that produces FDG gypsum, sir?
Many countries around the world have used FDG to reduce S in thermal power plants, chemical factories and obtained a source of high quality artificial gypsum, effectively solving the problem of environmental pollution from waste gas and solid waste and solve the problem of gypsum raw materials of the country.
Currently, in our country, there are a few factories that are trying to operate the FGD system, but the obtained gypsum is of low quality (in terms of purity, moisture), the resulting product is not commercially available because We use FDG receiver which is quite outdated.
So, to take the initiative in the source of gypsum in the country, what measures should be taken, sir?
In order to be proactive in the domestic source of gypsum raw materials, the effective solution that countries around the world have made is to take advantage of artificial gypsum sources in the process of reducing S from thermal power plants, chemical plants using use coal. This is a plan that achieves many goals, both solving the source of raw materials and thoroughly dealing with environmental problems. To do this, the State also needs a policy so that investors of thermal power plants and chemical factories are forced to invest in modern technology and equipment for the FDG system so that the gypsum can be obtained. used as ceiling panels, wall panels, unburnt materials and for many other industries, replacing imports and solving environmental pollution. At the same time, there must also be a policy for production facilities that have demand to use gypsum using artificial gypsum from thermal power plants and domestic chemical plants.
Thank you Sir!
Source: Electronic Construction Newspaper