JPH01294520A - Method for slaking naturally occurring light burned magnesia - Google Patents

Abstract

PURPOSE:To provide magnesium hydroxide with small energy and labor by pulverizing light burned magnesia prepared by calcining natural occurring magnesite to a specific particle diameter, mixing the resultant ultrafine powder with an aqueous solution of a strong alkaline agent at a specific pH and heating the obtained mixture up to a specified temperature. CONSTITUTION:Light burned magnesia prepared by calcining naturally occurring magnesite is pulverized to ultrafine powder having 5-30mu particle diameter. On the other hand, about 25kg strong alkaline agent is added and dissolved in about 9m<3> water in a reaction vessel to provide a solution at pH >=11. The above-mentioned magnesia in an amount of 3600kg is then charged into the afore-mentioned solution while stirring to raise the solution temperature up to >=100 deg.C and steam is stopped. In this state, stirring is carried out for >=1hr to complete slaking reaction. Six oxygen atoms attain active atoms in the form of free radicals by cleavage of the periclase type crystal structure in the light burned magnesia by the above-mentioned method and magnesium hydroxide capable of providing an industrial alkaline agent having extremely great reactivity is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a method of calcining naturally produced magnesite to form lightly calcined magnesia and subjecting it to a 4I-reaction reaction with water.

[Prior Art] Currently, slaked lime, caustic soda, magnesium hydroxide, etc. are commonly used as industrial alkali agents, and each is used depending on cost and physical/chemical properties.

[Problem to be Solved by the Invention 1] In particular, the reality is that magnesium hydroxide is synthesized using more energy and labor than magnesium in seawater.

The present invention is directed to i) naturally produced light calcined magnesia, which can synthesize this magnesium hydroxide at low cost and provide it to the market as an industrial alkali agent at low cost.
The purpose is to provide a τ-phase method.

[Means for Solving the Problems] The structure of the present invention to achieve the above object is to crush lightly calcined magnesia obtained by calcining naturally produced magnesite into an ultrafine powder of 5 to 30 microns, and add it to water with a strong alkali. Add the agent and increase the P of the liquid.
The gist of the method is to set H to 11 or more, add the above-mentioned open-fired magnesia while stirring, and heat the mixed liquid to 100° C. or more.

Magnesium hydroxide synthesized by the method of the present invention is a highly active hydrodel-containing magnesium hydroxide, and the applicant calls this product ``1-sanhydromag'' to distinguish it from other magnesium hydroxides. Therefore, for convenience, magnesium hydroxide synthesized by the method of the present invention is
I'll call it "Sun Hydro Mag."

Most of the light-burnt magnesia mentioned above is produced and imported in China, North Korea, and India. The raw ore is magnesai) (Mg
The main component is CO=), and the impurities are Herafuran!
b) (Ca2SiO+ + 1120) and lIa amount Noah 171. Contains X-telite (Mg2SiO+).

By calcining this raw ore at 820°C, magnesite becomes velclase-type MgO, the impurity herabhungite changes to rallite, and forsterite remains almost as it is.

Since the second light burnt magnesia is MgO, it should be able to be used as an alkaline agent as stated in the package, especially for flue gas desulfurization.
If it can be used as an alkaline agent for neutralizing acidic wastewater, hydroxymagnetium produced from seawater (hereinafter referred to as “
It can be supplied at about half the production cost of seawater mugs).
Big cost savings.

This saves energy, and many people who have focused on this point have conducted repeated tests in the past, but the response was actually worse than that of seawater mugs, and there was no demand for them.

The reason for this is that light calcined magnesia cannot be slaked well even if it is simply stirred with water or hot water. This was considered to be a fateful result of the berryclase crystal structure (a dense banking structure in which an M[I atom is surrounded by six 0 atoms) of lightly burnt magnesia.

However, the inventors discovered that by increasing the concentration of 011- ions in the cleavage solution having a berry crease structure by adding strong alkali agents such as aqueous ammonia or caustic soda, the 6 O atoms became active atoms in the form of 7-radicals. They found that.

Because it has this 7-ary radical atom, its reactivity becomes extremely high, resulting in a reaction rate that is 4-5-3 that of seawater maggots.

When synthesizing Sanhydromag, in order to increase the reaction rate of hydrolysis, the temperature of the synthesis liquid was set to 100"C or higher, and in order to create an M-cleavage of the base+arclace structure, a strong alkaline agent as mentioned in # was added, and the pH of the liquid was adjusted to room temperature. The reaction time should be 11 or more when measured with 1 hour or more, and the reaction should be completed with sufficient stirring.

[Example 1] 91 kg of water is placed in a 15+13 reaction tank equipped with an iron stirrer, and 25 kg of a strong alkaline agent is added while stirring, and the mixture is sufficiently dissolved. Subsequently, 3,600 kg of lightly burnt magnesia was added, mixed and stirred, and the liquid temperature was raised to 100°C or higher, and the addition of the mixture was stopped.

Stir in this state for 1 hour or more to complete the slaked reaction.

At the ILW point where the reaction has completely finished, inspect the inside of the reaction tank.Since the water has evaporated considerably and disappeared, add water to adjust the concentration to 10m3 (underwater Sanhydromag) and store. Transfer to tank. Ship from storage tank.

Sanhydromag differs from seawater mug in that it has an extremely low viscosity, so it can be transported and stored as a highly concentrated slurry (the example is a 40% slurry, but a 50% slurry is also possible).

[Effect of the invention 1 This Sanhydromag contributes to significant cost and energy savings as an alkali agent for depletion and an alkali agent for neutralization, as mentioned above, but it also has the following advantages: There is also α.

1) Calcium in seawater mags is contained in the form of Ca (Ofri2), so it reacts with S02 to form calcium sulfite (CaSOz) and form rock-like deposits. Since CaO is included in the form of Ralli) (Ca2SiJ), which does not react with acids, no calcium sulfite is formed and therefore no deposits occur.

2) Sanhydromag contains C, which causes corrosion of equipment.
Since it does not contain g, there is less damage to equipment.

Patent applicant: Santaray Co., Ltd. Procedural amendment 19863 1/& day Commissioner of the Patent Office Kunio Kogawa C1 2. Name of the invention How to slake natural light burnt magnesia 3. Person who makes corrections Relationship to the case Patent applicant Address: 65 Chibarasaki, Toyama City, Toyama Prefecture Name Santaray Co., Ltd.

Claims (1)

[Claims] 1) Lightly calcined magnesia made by calcining naturally produced magnesite is crushed into ultrafine powder of 5 to 30 microns, a strong alkaline agent is added to water, the pH of the liquid is adjusted to 11 or more, and the light calcined magnesia is mixed with stirring. A method for slaked naturally produced light-burnt magnesia, characterized by charging the mixture and heating the mixture to 100°C or higher.