One of the problems that most manufacturers ignore is that the active content of magnesium oxide and the content of magnesium oxide are always mixed. Here is a brief introduction:
MgO content: 85% refers to the content of MgO in the whole light burning powder.
Activity content: 65% refers to 65% of magnesium oxide that can react with magnesium chloride and water to form magnesite gel. For example, magnesium hydroxide, magnesium carbonate, overburned magnesium oxide (these are impurities contained in magnesium oxide itself or substances generated during storage, but not harmful substances) do not participate in the reaction.
The content of MgO is 85%. Theoretically, its active content should be 65%. However, because the temperature of MgO is too low and less than 600 ℃, it is light burned powder. Its active content may reach 65% or even more than 65%, but its MgO content is less than 85%; 2. The temperature of MgO is too high and more than 800 ℃ or even 1000 ℃ and it is calcined for a long time The activity of MgCO3 is basically burnt and sintered, and then it becomes magnesium carbonate (MgCO3), also known as bitter earth powder. Although it is a good refractory material, it can not be used in magnesite products. However, magnesium oxychloride cement cementitious material, which uses the activity of magnesium oxide and magnesium chloride solution to produce 518 crystalline phase, and then adds some fillers and modifiers to improve the product performance.
There are also various external problems. The content is 85% and the active content is 65%. If you store it improperly (damped or mixed with other substances), its active content will also be reduced. But this is only a small change, which may drop to 64%, 63%, 62% and so on, but from 55% to 65% it is within the qualified range. At the same time, the temperature of the workshop in the production process can not guarantee that your magnesium oxide activity will remain at 65% all the time in the application process. Not to mention that many users' MgO is less than 65% at all. Some of them said that the content of MgO they bought was 85%. The raw material manufacturers also told him that the activity must reach 65%. So they sent some samples for us to test on behalf of them. The results were quite unexpected. Actually, the activity is only over 20%, and some even over 10%. That's not much to say. It's only a part of it. Some can still say that the active content is 65%. After testing, it's over 50%. Some can reach more than 60%, but it still can't reach 65%. This may be the past affected by various conditions.
In the case of determining the correct calculation basis, it should also be noted that the content of active magnesium oxide in light burned magnesium oxide is not constant. In the process of storage, due to moisture or absorption of water in the air, brucite Mg (OH) is formed, thus reducing the content of active Mg0, which is particularly prominent in the south of China. Therefore, with the use of different manufacturers, different raw materials at different times, different The storage time, the content of active Mg0 in the light burned powder is measured irregularly, and the composition of the proportion is adjusted irregularly, that is to say, the dynamic and scientific proportion is used to overcome the phenomenon of returning brine and frost.
It is unscientific and nonstandard for some producers to produce brine with high Baume degree in winter and low Baume degree in summer or adopt a specific proportion from one end. Because the quantitative relationship of molar ratio of reaction is ignored So remind the magnesite industry manufacturers, as well as want to involve in this industry friends to remind. If the content of MgO is 85%, its active content is 65%. The content of MgO can not be directly equivalent to the active content of MgO. These are two different concepts, and the actual application of magnesite products is active magnesia. What's more, the basis of the formula is based on the activity of magnesium oxide. Without this basis, if your formula just corresponds to the activity of magnesium oxide at 65%, your product will be half successful this time. The possibility of product problems is correspondingly reduced Try to do raw material control is the first! Activity test is the most important Scientific matching is the key! The modifier must be added!
