膨润土(Bentonite)按译音、成因及用途又称斑脱岩、膨土岩等，是以蒙脱石(也称微晶高岭石、胶岭石)为主要成分的粘土岩—蒙脱石粘土岩,常含少量伊利石、高岭石及沸石、长石、方解石等。蒙脱石为少量碱及碱土金属的含水铝硅酸盐矿物。

由于蒙脱石层间水和层间可交换阳离子存在，按蒙脱石所含可交换阳离子种类、含量和结晶化学性质等,可将膨润土划分为钠基膨润土(碱性土)、钙基膨润土(碱土性土)和天然漂白土(酸性土或酸住白土)三种。

物理性质：

颜色一般为白色,淡黄,因含铁量变化又呈浅灰、淡绿粉红、褐红、黑杂等色。具蜡状、土状或油脂光泽。

化学成份：

膨润土的主要化学组分是二氧化硅(SiO₂),三氧化二铝(Al₂O₃)和水。氧化铁和氧化镁含量有时也较高。此外,钙、钠、钾等常以不同含量存在于膨润土中。膨润土的Na₂O和CaO含量对膨润土的物理化学性能和工艺技术性能影响颇大。

理化性能：

膨润土具有吸湿性，能吸附8～15倍于本体积的水量。吸水后膨胀，能膨胀数倍，可达30余倍。在水介质中能分散呈胶体悬浮液，这种悬浮液具有一定的粘滞性、触变性和润滑性。它和水、泥或砂等细碎屑物质的掺合物有可塑性和粘结性。有较强的阳离子交换能力。对各种气体、液体、有机物质有一定的吸附能力，吸附量可达5倍于它的重量，具有表面活性的酸性漂白土能吸附有色物质。

 膨润土的理化性能主要取决于它所含的蒙脱石种类和含量。一般钠基膨润土较之钙基或镁基膨润土的物理化学性质和工艺技术性能优越。主要表现在：吸水速度慢，但吸水率和膨胀倍数大；阳离子交换量高；在水介质中分散性好，胶质价高；它的胶体悬浮液触变性、粘度、润滑性好，pH值高；热稳定性好；有较高的可塑性和较强的粘结性；热湿拉强度和干压强度高。所以钠基膨润土的使用价值和经济价值较高。

钠基膨润土的应用：

①在机械铸造业中，可作铸造型砂、粘结剂，可以克服铸件的“夹砂”“起皮”现象，降低铸造件废品率，***铸件的精度和光洁度。

②在造纸工业中，用作纸张的填充剂，增强纸张的光亮度。

③利用本产品的强粘结性能，用于白乳胶、地板胶、浆糊等的制作。

④因其有稳定的悬浮性、增稠性，能有效地托浮分散粉体，可作水性涂料的增稠防沉淀助剂。

⑤同时利用它的优良的分散性和膨胀性，高造浆率、低失水量及胶体性能和剪切稀释能力，可以用作钻井泥浆用钠土。

铸造性能：

乳胶、涂料性能指标：

英文版The English version

Sodium machine swelling soil

Bentonite clay (Bentonite) in transliteration, causes and use is also called spot to take off the rock, Bentonite, etc., is based on montmorillonite (also known as microcrystalline kaolinite, montmorillonite) as the main component of clay rock - montmorillonite clay rock, often contain small amounts of illite and montmorillonite, zeolite, feldspar, calcite, etc. Montmorillonite is a small amount of alkali and alkaline earth metal hydrous aluminum silicate minerals.

Because of montmorillonite interlayer water and interlayer exchangeable cations, in accordance with the montmorillonite content of exchangeable cation type, content and crystal chemistry, etc., can be divided into sodium base bentonite bentonite (alkaline soil), calcium base bentonite (alkali) native soil and natural bleaching earth lived (acidic soil or clay) three kinds.

Physical properties:

Color general for white, weak yellow, because of iron content change in light grey, light green, pink, brown color, red, black etc. With waxy luster, earthy or grease.

Chemical composition:

Bentonite silica (SiO2) is the main chemical composition, 3 oxidation 2 aluminium (Al2O3) and water. Iron oxide and magnesium oxide content sometimes higher. In addition, calcium, sodium, potassium, etc often exist in different content in bentonite. Bentonite Na2O and CaO content on the physical and chemical properties of bentonite and technology performance impact is quite big.

The physical and chemical properties:

Bentonite has hygroscopicity, can adsorption 8 ~ 15 times the volume of water. After water absorption expansion, can expand to several times, can reach more than 30 times. That can disperse in water medium in colloidal suspension, the suspension has certain viscosity, thixotropy and lubricity. It with water, mud or sand and fine detrital material blending has plasticity and sintering. Has the strong cation exchange capacity. For a variety of gases, liquids, has certain adsorption ability of organic matter, up to 5 times the maximum adsorption of its weight, has the surface activity of the acid bleaching earth can adsorption non-ferrous material.

Physico-chemical properties of the bentonite contained mainly depends on its content and the types of the montmorillonite. General sodium base bentonite than calcium or magnesium based bentonite technologies of chemical and physical properties and superior performance. Mainly displays in: the water absorption speed is slow, but multiple large water absorption rate and inflation; High cation exchange capacity; Good dispersibility in water medium and high colloid valence; Its thixotropy and viscosity, good lubricity, colloidal suspension of high pH value; Good thermal stability; Have higher plasticity and strong caking property; Hot wet tensile strength and high dry strength. So the use of sodium base bentonite value and economic value is higher.

The application of sodium base bentonite:

(1) in the mechanical casting industry, as a foundry sand, binder, which can overcome the "sand" of casting "peeling phenomenon, reduce the casting scrap rate, ensure the accuracy of castings and finish.

(2) in the papermaking industry, is used as paper filler, enhance the brightness of paper.

3. Use of this product strong bonding performance, production for white latex, floor glue, paste, etc.

(4) because of its stable levitation, thickening, can effectively support distributed powder, as a water-based paint thickening additives precipitation.

5. At the same time take advantage of its excellent dispersibility and expansibility, high mud making rate, low fluid loss and colloidal properties and shear dilution ability, can be used as a drilling mud used sodium soil.

The casting performance:

Project target level

Hot wet tensile strength

Wet strength

Colloid rate

Expansion ratio

200 mesh by volume

The moisture content

Mud making rate

mpa

mpa

%

%

%

Level 1

2.5

0.0049

100

25 to 30

95

10 or less

16 or higher

The secondary

2-2.5

0.00294 ~ 0.0049

100

18 ~ 25

90

12 or less

15 or less

Emulsion, coating performance indicators:

project

White degree

viscosity

Colloid valence

The PH

The moisture

Expansion of capacity

Particle size

%

Ps

15 ml/g -

%

Ml/g -

indicators

75 or more

2.8 or higher

90 or more

8 ~ 10

10 or less

Two or more

300-325