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沉淀碳酸钙

PCC st和s for 沉淀碳酸钙—also known as purified, refined or synthetic calcium carbonate. 它与其他类型的碳酸钙(如石灰石、大理石)有着相同的化学公式 和 粉笔:碳酸钙. 钙, carbon 和 oxygen atoms can arrange themselves in three different ways, to form three different calcium carbonate minerals. 沉淀碳酸钙和磨细碳酸钙最常见的排列形式是被称为方解石的六角形. 有几种不同的方解石晶体形式:偏斜面体、菱形体和棱形体. 不太常见的是文石，它具有离散的或聚集的针状正交晶体结构. Rare 和 generally unstable is the vaterite calcium carbonate mineral.

 

SMI_Scalenohedral
Calcium carbonates, including PCC, are considered to be non-toxic. 在美国.S., 美国食品和药物管理局确认碳酸钙为GRAS(一般公认为安全). As long as the PCC meets certain purity requirements, it can be used as a direct food additive, 作为药品或与食品接触的纸制品中的间接添加剂. 类似的接受和批准存在于世界各地，pcc在这些应用中广泛使用. 点击下面的“沙巴体育买球网”链接，查询pcc在这些与健康有关的用途中使用的具体规定, 或在MSDS链接下载材料安全数据表，包括专业矿物公司.SMI公司的PCC产品.

 

当 Did 沉淀碳酸钙 (PCC) Manufacture Begin?
PCCs have been made commercially for a long time—since 1841. The first producer was the English company, John E. 他是有限公司., 他们用苏打灰和二氧化碳处理氯酸钾生产过程中剩余的氯化钙，形成他们所谓的沉淀粉笔. In 1898, a new factory was built in Birmingham using the milk of lime process, which is described in more detail below. This PCC operation is now part of the Performance 沙巴体育app官网登录 group of SMI.

PCC在美国的生产.S. 始于1938年，当时C.K. 亚当斯的威廉姆斯公司, 麻萨诸塞州, began to make PCC using the limestone from their adjacent mine. This plant was acquired by Pfizer in 1962, 在成立我们的母公司时，成为了SMI的Performance 沙巴体育app官网登录集团的一部分, 沙巴体育APP., in 1992.

 

SMI_UltraPflex SMI_Albafil SMI_HeavyPCC

 

How Is 沉淀碳酸钙 (PCC) Made?

几乎所有的PCC都是由石灰直接碳化而成，即石灰奶工艺. The milk of lime process is simple in concept:

  • 我的 high purity calcium carbonate rock.

  • 将岩石压碎到加工所需的颗粒大小——小石块或粉末.

  • Separate some of the impurities from the crushed rock.

  • Calcine (heat) in a kiln to 1850° F, which takes the calcium carbonate apart, forming lime (CaO) 和 carbon dioxide gas (CO2). The carbon dioxide can be captured for reuse. CaCO3 + Heat→CaO + CO2↑    

  • Add the lime to water to form calcium hydroxide (hydrated lime or slake).
    2 . CaO + H2O→Ca(OH)       

  • Separate out additional impurities from the slaked lime.

  • Combine the captured carbon dioxide with the slaked lime. 碳酸钙发生了变化，由于它不溶于水，就析出了.
    Ca(OH)2 + CO2→CaCO3↓+ H2O 

  • Separate additional impurities 和 grit from the PCC slurry. 

  • 如果PCC是用于造纸厂或装运到乳胶漆厂, the lower solids slurry may be used as is, or processed to bring up the solids level, then tested before transfer or shipment.

  • If the PCC is to be used as a dry product, 泥浆被脱水, 干, 磨碎的, 包装和测试.

SMI_Ultrabulk SMI_Megafil SMI_Opacarb-A40

 

While the process is simple on a laboratory scale, 大规模商业化生产沉淀碳酸钙需要大量的过程控制和工艺技术 保证 right size, uniformity, shape, surface area 和 表面化学. This body of PCC technology developed by 特种矿物 研究中, is what makes SMI PCCs outst和ing in quality 和 consistency.

What Is 沉淀碳酸钙 (PCC) Made From?

PCC通常由一种叫做石灰石的高纯度碳酸钙岩石制成. 专业矿产公司. (重度)使用 高质量的 limestone sources for its PCC products, including some from the SMI limestone mine in Adams, 麻萨诸塞州, which has been in operation for more than 150 years.

这种石灰石沉积物是史前海洋动物的外壳和骨架被埋在海底厚厚的一层的结果. These shells 和 skeletons were largely composed of calcium carbonate. 在5亿年的时间里，这个矿床处于高温高压之下, 和 the deposit changed to a coarsely crystallized limestone. 沉积物中所有的有机物都被氧化了, 这个过程叫做成岩作用.

If this kind of geological process continues a very long time, 晶体变得非常小, 形成大理石, an extremely hard form of calcium carbonate. 如果时间, 温度 和/or 压力s are not great, the seabed only partially metamorphoses, 和 the result is very soft chalk, such as that forming the White Cliffs of Dover in Engl和. In chalks, remnants of animal shells 和 skeletons are often still seen.

为什么要进行所有的处理?

两个原因. 第一个, 在PCC过程中有几个点碳酸钙可以被提纯, 除去除去碳酸钙以外的大部分岩石——任何石灰石矿床中总有一些杂质. 这些包括长石和其他 silicaceous minerals, as well as heavy metals.

Second, the PCC process allows SMI to grow crystals of different shapes. The particle formed is dictated by the control of reaction time, 温度, 搅动, 压力, 二氧化碳添加速率, 和 post-crystallization processing. 这些shapes-clustered针, 多维数据集, 棱镜, rhombohedrons—have different physical properties such as powder density, 表面积和吸油性, 这使得它们在许多应用中表现出色，而碳酸钙不能表现得很好. 其中一些形状的扫描电子显微图(sem)显示在本页上. 

The precipitation process also allows the growing of very fine particles, 深达纳米或百分之一微米，比仅仅研磨石灰石要细得多. 这些超细纳米pcc具有需要高性能的特殊应用. 点击这里了解更多关于纳米pcc, SMI已经制造了超过25年.

What Is Unique About A 沉淀碳酸钙?

不同的形状使PCC在密封剂中起到功能性添加剂的作用, 粘合剂, 塑料, 橡胶, 油墨, 纸, 药品, 营养补充剂 和 many other dem和ing applications. 配方师可以选择一种形状, 和 the physical properties that result from that shape, that gives the best performance in the end use.

在PCC过程中, products can be made with very small sizes, 具有高表面积, 高的油吸收, 和/or with different powder bulk densities— from 超低, 超高密度粉.

为什么有些pcc涂层?

PCCs are often coated with a low percentage (1-3 percent) of a fatty acid, 如硬脂酸, 或其他有机物质, 用于非水系统. 这些涂料增加了PCC在聚合物或溶剂中的分散性以及它与聚合物或溶剂的相容性, which in turn maximizes the performance 和 efficiency of the PCC.

涂层的选择取决于PCC将用于的聚合物类型和所期望的性能. As polymers vary widely in polarity 和 solubility constants, 不同的有机物被选择以提供最佳的相容性和/或性能的最佳平衡.

沉淀碳酸钙和研磨碳酸钙(GCC)有何不同??

In chemical composition, they are the same. PCC比制造它的石灰石更纯净，二氧化硅和铅的含量也更低.

PCC的形状和大小不同于磨细碳酸钙(GCC). 在高倍放大条件下，GCC呈不规则的菱形. PCC晶体形状取决于产品，颗粒更均匀和规则.

也就是说，在GCC中颗粒尺寸的分布比相同尺寸的PCC要宽得多, 比PCC中有更多的大颗粒和小颗粒, 并且最大颗粒的尺寸(“顶部尺寸”)对于GCC比PCC要大得多. PCC较低的顶部尺寸在塑料中提供了比GCC更好的抗冲击能力. 较窄的粒径分布允许产生高吸油率, 在某些应用中很有用.

These differences can be quickly seen 在这些 photos of a PCC 和 a GCC of the same median particle size, 0.7微米.

 

PCCvsGCC_Performance_in_LWC_纸s

 

特种矿物 沉淀碳酸钙s

SMI is the world’s largest manufacturer of PCCs, with an output of over 4 million tons of PCC each year.

我们的一些用于纸张和纸板填充和涂料的PCC产品包括Opacarb®, Megafil®, 和 Velacarb® precipitated calcium carbonates.

对食物, 营养补充剂, pharmaceutical 和 personal care products, 八款ViCALity®USP/FCC沉淀碳酸钙系列和五款CalEssence®超低铅pcc系列均在亚当斯生产, 麻萨诸塞州, 在美国.S. 五种SturcalTM和Calopake®EP PCC医疗保健等级在美国伯明翰生产.K.

各种聚合物和水基工业产品都使用Albacar®, Albaglos®, 和Super-Pflex®pcc, 以及纳米pcc, Ultra-Pflex®, Multifex-MM® 和 a series of Thixo-Carb® PCCs, 这个词来自亚当斯, 麻萨诸塞州, 在美国.S. Calopake®PCC和Calofort®nano PCC来自SMI的伯明翰工厂.