橄榄石 olivine sand
1、镁橄榄石耐火材料的主要组成
镁橄榄石耐火材料的化学组成： (MgO)=37％～62％，m(MgO)／m(SiO2)波动于0.95～2.00。主晶相镁橄榄石 (M2S)=65％～75％。其余为MF和其他矿物。m (MgO)／m(SiO2) ＞1.33者往往含有少量方镁石。
橄榄石熔点较高，达1890℃，它与顽辉石都是MgO—SiO2二元系中的二元化合物。它与MgO的共熔温度很高，达1850℃。与此相反，它与顽辉石共存出现液相的温度却很低，仅1557℃。
Chemical composition of magnesium olive-stone refractory: (MgO)=37%~62%, m (MgO) / m (SiO2) fluctuating from 0.95 to 2.00. Main crystal phase magnesium olivine (M2S)=65%~75%.The remainder are MF and other minerals.People with m (MgO) / m (SiO2)> 1.33 tend to contain a small amount of magnite.
The perivite melting high to 1890℃, which are binary compounds in the MgO-SiO2 binary system.Its co-melting temperature with the MgO is high, up to 1,850℃.In contrast, it can coexist with stubborn pyroxene for a liquid phase at a low temperature, only 1557℃.
镁橄榄石在还原状态同铁直接接触时，由于Mg2+和Fe2+半径相近，镁铁置换形成无限固溶体。从而使系统出现液相的温度降低，制品的耐火度也随之降低。而且，在氧化气氛下，2FeO·SiO2在700℃时即可分解为Fe2O3和SiO2。这些Fe2O3在开裂面和晶粒界面析出。并在1400℃以上与M2S反应形成MF和MS。FeO的氧化和MF的生成都伴有很大的体积膨胀。若此种Fe2O3析出后，随后在还原气氛下，再次成为2FeO·SiO2而消失，但在橄榄石晶粒上形成的裂隙却仍然存在。故当此种材料中含铁的氧化物的量较高或受铁质侵蚀后，极易在气氛性质频繁变动的情况下产生松散作用。
When magnes olivite is in direct contact with iron in the reduced state, magnite displacement forms an infinite solute due to the proximity of Mg2 + and Fe2 + radii.Thus, the temperature of the liquid phase in the system decreases, and the fire resistance of the product also decreases.Moreover, in an oxidative atmosphere, the 2FeO SiO2 can be decomposed into Fe2O3 and SiO2 at 700℃. These Fe2O3 were precipitated at the cracking surface and at the grain interface.And reacted with M2S above 1400℃ to form MF and MS.Both the oxidation of Feo and the MF generation are accompanied by a large volume expansion.If such Fe2O3 is out, it then becomes 2FeO SiO2 in the reducing atmosphere, but the crack formed on the olivine grain remains.Therefore, when the amount of iron-containing oxide in this material is high or eroded by iron, it is easy to produce a loose action under the condition of frequent changes in atmosphere properties.
当原料中含铁氧化物量较高时，对材料的抵抗高温性能和体积稳定性有影响，FeO氧化及MF形成的膨胀松散效应，也使材料难于烧结。故橄榄石中FeO的质量分数大于10％时，不宜作为耐火材料。
When the amount of iron oxide in the raw material is high, it affects the resistance to high temperature performance and volume stability of the material, and the expansion and loose effect of FeO oxidation and MF formation also makes the material difficult to burn.Therefore, when the quality score of FeO in perivine is greater than 10%, it should not be used as a refractory material.
镁橄榄石烧结制品的生产
此种制品的生产工艺与镁砖基本相同。若为保证原料中的SiO2和MS都形成M2S，形成MF，以提高制品的高温性能，需加入轻烧MgO或死烧镁砂。以细粉的形式加入，可强化制品的基质。由于镁橄榄石生熟料都是瘠性料，宜用黏结性较高的结合剂，如浓度较大的纸浆废液与MgCl2溶液等，用量依成型方法而定，所含水分的总质量分数约为3％～5％。
制品的烧成与熟料煅烧相同，应控制在氧化气氛下进行。此种制品烧成范围较窄。烧成温度依基质中优(MgO)／m(SiO2)而定，m(MgO)／m(SiO2)较高者，一般烧成温度在1550℃左右。
Production of magnesium olivine sintering products
The production process of this product is basically the same as the magnesium brick.In order to ensure that both SiO2 and MS in the raw material form M2S and MF to improve the high temperature performance of the product, light burning MgO or dead burning magnesium sand should be added.Add in the form of fine powder, which can strengthen the substrate of the product.Because magnesium olivine raw clinker is barren material, should use high adhesive binder, such as large concentration of pulp waste liquid and MgCl2 solution, the amount according to the molding method, the total quality score of the water content is about 3%~5%.
The firing of the product is the same as the clinker calcination, and shall be controlled in an oxidation atmosphere.The product has a narrow firing range.The firing temperature depends on medium matrix (MgO) / m (SiO2) and higher m (MgO) / m (SiO2), the firing temperature is generally about 1550℃.
4.1强度和荷重软化温度。
由于镁橄榄石的熔点较高，MgO-M2S共熔温度也很高，耐火度很高，在1800℃以上。此种制品也具有较高的高温强度。荷重软化温度可达1600℃。故此种制品可用于高温下受重负荷较大的情况。但是，当优(MgO)／m(SiO2)较低时，因其中有顽辉石共存，故耐火度和高温强度都较低。
Due to the high melting point of magnesium olivite, the MgO-M2S co-melting temperature and fire resistance are above 1800℃.This product also has a high, high-temperature strength.The load weight softening temperature is up to 1600℃.Therefore, this product can be used for high heavy load under high temperature.However, when optimal (MgO) / m (SiO2) is low, the refractory resistance and high temperature strength are low due to the coexistence of stubborn pyroxene.
4.2抗热震性
此种制品中的M2S热膨胀性较高，20～1500℃下平均线膨胀系数约为11×10-6℃-1，但在温度变化时无晶型转变。故具有一定的抗热震性。
The M2S in this product is thermoinflated with an average expansion coefficient of about 1110-1-6 at 20 to 1500℃, but an amorphous transition at temperature change.Therefore, it has a certain heat-shock resistance.
4.3耐侵蚀性
镁橄榄石耐火材料是一种弱碱性耐火材料。对Fe2O3侵蚀有较强的抵抗性，有一定的抗碱性渣能力。m(MgO)／m (SiO2)较高者，即矿物组成主晶相镁橄榄石所占比例很高，或在主晶相以外还有少量方镁石者抗渣性较好。但是，由于M2S同CaO接触，从1400℃起即可反应形成易熔的CMS，同A12O3接触在1250℃以上就易形成堇青石。此种堇青石在1460℃下分解熔融，故此种制品既不宜用在受强碱性渣侵蚀之处，也应避免直接与粘土耐火材料和高铝耐火材料接触。由于M2S在高温下(如在1650℃以上)可被碳素材料分解，故应避免与它接触。
Magnesium olivine refractory is a weakly alkaline refractory material.It has a strong resistance to Fe2O3 erosion and has a certain resistance to alkaline slag.Higher m (MgO) / m (SiO2), a high proportion of mineral composition, or a small amount of calcite beyond the main crystal phase, have good slag resistance.However, since M2S is in contact with CaO, a molten CMS can be formed from 1400℃, and lapidite is easily formed in contact with A12O3 above 1250℃.This lapite is decomposed and melted at 1460℃, so this product should not be used where eroded by strong alkaline slag or avoid direct contact with clay refractory and high aluminum refractory.Since the M2S can be decomposed by a carbon material at high temperatures (such as above 1650℃), its contact should be avoided.
由于此种制品中的M2S与铁直接接触时，易形成[M2S—F2S]，使出现液相的温度降低，而且铁氧化物在气氛变动下易导致晶粒松散，故不宜在气氛经常变动的情况下使用。
Since M2S in this product has direct contact with iron, [M2S-F2S] reduces the temperature of the liquid phase, and iron oxide easily leads to loose grain under changes in the atmosphere, it is not suitable to be used when the atmosphere changes frequently.
