1、17. Eh - pH - DIAGRAMS (Pourbaix-diagrams)Eh-pH-diagrams show the thermodynamic stability areas of different species in an aqueous solution. Stability areas are presented as a function of pH and electrochemical potential scales. Usually the upper and lower stability limits of water are also shown in
2、 the diagrams with dotted lines. Traditionally these diagrams have been taken from different handbooks12. However, in most handbooks these diagrams are available only for a limited number of temperatures, concentrations and element combinations.Eh-pH 图显示不同物种在水溶液中的热力学稳定区。稳定的地区作为一个潜在的尺度和电化学作用的 pH 值。通常
3、上、水下稳定极限也与虚线图所示。传统上，这些图已从不同的 handbooks12。然而，在大多数手册这些图是只有数量有限的温度，浓度和元素组合。The Eh-pH module of HSC Chemistry allows the construction of diagrams in a highly flexible and fast way, because the user can draw the diagrams exactly at the selected temperature and concentration.HSC 化学 Eh-pH 模块允许在一个高度灵活和快速的方式
4、图解，因为用户可以画出图形，在选定的温度和浓度。The Eh-pH-module is based on STABCAL - Stability Calculations for Aqueous Systems - developed by H.H. Haung, at Montana Tech., USA9,10.Eh-pH 模块是基于 stabcal 稳定性计算水系统由 H.H.黄发达，蒙大纳科技，usa9,10。17.1 IntroductionEh-pH-diagrams are also known as Pourbaix Diagrams according to author o
5、f the famous Pourbaix diagram handbook12. The most simple type of these diagrams is based on a chemical system consisting of one element and water solution, for example, the Mn-H2O-system. The system can contain several types of species, such as dissolved ions, condensed oxides, hydroxides, oxides,
6、etc. The Eh-pH-diagram shows the stability areas of these species in the redox potential-pH-coordinates.Eh-pH 图也称作 Pourbaix 图根据著名的 Pourbaix 图 handbook12 作者。这些图的最简单的类型是基于化学系统组成的一个元素和水的解决方案，例如，在 mn-h2o-system。该系统可以包含多种类型的物种，如溶解离子，浓缩的氧化物，氢氧化物，氧化物，等电位-pH 图显示在氧化还原电位 pH 这些物种的稳定区域的坐标。Usually the redox pote
7、ntial axis is based on the Standart Hydrogen Electrode (SHE) scale designated Eh, but other scales can also be used. The redox potential of the system represents its ability to change electrons. The system tends to remove electrons from the species when the potential is high (Eh 0). These conditions
8、 may exist near the anode in the electrochemical cell, but can also be generated with some oxidizing agents (Cu + H2O2 = CuO + H2O). In reducing conditions, when potential is low (Eh 0）。这些条件可能存在在电化学电池的阳极，但也可以与一些氧化剂（H2O2 生成 Cu +铜+ H2O =）。在还原条件下，当为低电位（Eh0），该系统能够提供电子的物种，例如，与阴极电极或与还原剂。The pH of the syst
9、em describes its ability to supply protons (H(+a) to the species. In acid conditions (pH 7) the concentration of protons is low.pH 值的系统描述其提供质子的能力（H（+）的种类。在酸性条件下（ pH7）质子的浓度较高，在碱性条件下（pH7）的质子浓度低。Usually a large amount of different species exist simultaneously in the aqueous mixtures in fixed Eh-pH-cond
10、itions. The Pourbaix diagrams simplify this situation a lot by showing only the predominant species which content is highest in each stability areas. The lines in the diagrams represent the Eh-pH-conditions where the content of the adjacent species is the same in the equilibrium state. However, thes
11、e species always exist in small amounts on both sides of these lines and may have an effect on practical applications.通常一个大的不同物种的数量同时存在固定的 Eh-pH 条件水混合物。Pourbaix 图简化这种情况很多只显示优势种，内容是每个稳定性最高的地区。图中的线代表 Eh-pH 条件下相邻物种的内容是在平衡状态下相同。然而，这些品种都存在少量的这些线的两侧，可能对实际应用的影响。The lines in the diagrams can also be represe
12、nted with chemical reaction equations. These reactions may be divided into three groups according to reaction types:图中的线也可以用化学反应方程式。这些反应可分为三组，根据反应类型：1. Horizontal lines. These lines represent reactions that are involved with electrons, but are independent of pH. Neither H(+a)-ions nor OH(-a)-ions pa
13、rticipate to these reactions.1 水平线。这些线代表的反应，涉及电子，但独立的博士没有 H（+）离子和 OH（-）-离子参与反应。2. Diagonal lines with either positive or negative slope. These lines represent reactions that are involved with both electrons and H(+a)-and OH(-a)-ions.2。对角线或正或负的斜率。这些线代表的反应，涉及电子和 H（+）和（-）-离子哦。3. Vertical lines. These l
14、ines represent reactions that are involved either with H(+a)- or OH(-a)-ions, but are independent of Eh. In other words, electrons do not participate with these reactions.3 垂直线。这些线代表反应，可能与 H（+）或（- ）-离子哦，但独立的啊。换句话说，电子不参与这些反应。The chemical stability area of the water is shown in the Eh-pH-diagrams with
15、 dotted lines. The upper stability limit of water is based on the potential when the oxygen generation starts on the anode. It is specified by the reaction:水的化学稳定性区域是在虚线的 Eh-pH 图所示。水上稳定极限是基于势当氧代开始在阳极。它是由指定的反应：2 H2O = O2(g) + 4 H(+a) + 4 e-2 H2O = O2（ g）+ 4 H（+）+ 4The lower stability limit is based o
16、n hydrogen formation on the cathode. It is specified by the reaction:较低的稳定极限是基于阴极上氢的形成。它是由指定的反应：2 H(+a) + 2 e- = H2(g)2 H（+）+ 2 E = H2（g）The construction of the diagrams with HSC Chemistry EpH module is quite a simple task. However, several aspects must be taken into account when specifying the chem
17、ical system and analyzing the calculation results, for example:用 HSC-Chemistry 弗模块图的建设是一个相当简单的任务。然而，几个方面必须考虑指定化学系统分析计算结果，例如：1. A basic knowledge of chemistry, aqueous systems and electrochemistry or hydrometallurgy is always needed in order to draw the correct conclusions.1。一个基本的化学知识，水系统和电化学或湿法总是为了得
18、出正确的结论。2. The EpH module carries out the calculations using pure stoichiometric substances. In practice minerals may contain impurity elements and the composition may deviate slightly from the stoichiometric one.2。弗模块进行计算，采用纯化学物质。在实践中可能含有的杂质元素和矿物组成可能稍微偏离化学计量。3. There are always some errors in the ba
19、sic thermochemical data of the species. This may have significant effect on the results, especially if the chemical driving force of the reaction is small. Usually small differences between Pourbaix diagrams from different sources can be explained by the slightly different basic data used.3。总有一些物种的基
20、本热化学数据的一些错误。这可能会对结果有显著的影响，特别是如果该反应的化学驱动力小。通常小差异 Pourbaix 图从不同的来源可以通过使用略有不同的基本数据的解释。4. Sometimes data for all existing species is not available from the HSC database or from the other sources. This will distort the results if the missing species are stable in given conditions. The missing unstable sp
21、ecies will have no effect on the results.4。有时数据中的所有现存的物种是无法从数据库或从其他来源的造血干细胞。这会扭曲结果如果丢失的物种是在特定条件下稳定。失踪的不稳定的物种会对结果没有影响。5. The EpH module does not take into account the non-ideal behavior of aqueous solutions. However, in many cases these ideal diagrams give a quite good idea of the possible reactions
22、in aqueous solutions, especially if the driving force of the reactions is high.5。弗模块没有考虑到溶液的非理想行为。然而，在许多情况下，这些理想图给出可能的反应的一个相当好的主意在水溶液中，特别是如果该反应的驱动力是高。6. Thermochemical calculations do not take into account the speed of the reactions (kinetics). For example, the formation of the SO4(-2a) ion may be a
23、 slow reaction. In these cases metastable diagrams created by removing such species from the system may give more consistent results with the experimental laboratory results.6。热化学计算不考虑反应的速度（动力学）。例如，在形成 SO4（2A）离子可能是一个缓慢的反应。在这些情况下，亚稳态图，从系统中除去这些物种创造了可以提供更一致的结果与实验结果。The HSC user must be very careful whe
24、n drawing conclusions from Eh-pH-diagrams due to these limitations and assumptions. However, these diagrams may offer extremely valuable information when combining the results with the experimental work and with a good knowledge of aqueous chemistry. There is no universal kinetic or thermochemical t
25、heory available, which could entirely substitute traditional experimental laboratory work with pure theoretical calculation models.HSC 的用户必须非常小心，当得出结论 Eh-pH 图由于这些限制和假设。然而，这些图可以提供极有价值的信息时，将结果与实验工作和与水化学知识好。有没有通用的动力学、热化学理论可用，可完全替代传统的纯理论计算模型实验的实验室工作。More information on Eh-pH-diagrams, calculation method
26、s and applications can be found from different handbooks, for example, from the Pourbaix Atlas12.在 Eh-pH 图计算方法和应用的更多信息，可以发现不同的手册，例如，从儿 atlas12。17.2 Chemical System SpecificationsFig. 1. Selecting elements and species for the Eh - pH - diagram.The EpH Diagram selection in the HSC main menu will show
27、the EpH-form, Fig. 1. The user must specify the chemical system, which will be used to calculate the diagram in this form. Assume that system contains Cu, S and H2O. The following steps should be specified in order to create the diagram:在主菜单中选择 HSC 弗图将显示弗形，图 1。用户必须指定的化学系统，这将被用来计算这种形式的图。假设系统含有 Cu，S 和
28、 H2O。以下步骤应该被指定为创建图表：1. Select Main Element: Select one element from the list. This element will be used as the “main” element in the first diagram, i.e. all species, which are shown in the diagram, will contain this element. The user can easily change the main element selection later on in the diagr
29、am form. The Cu has been selected in this example.1。选择的主要因素：从列表中选择一个元素。本单元将作为第一个图的“主要”元素，即所有的物种，这是图中所示，将包含此元素。用户可以很容易地改变的主要元素的选择，后来在图的形式。铜已在本例中选择。2. Select Other Elements: Select other elements to the system. Up to 7 elements can be selected but it is recommended to use less, because large amount of
30、 elements and species increase calculation time and could cause some other problems. S has been selected in this example. Note: It is not necessary to select H and O, because these are always automatically included.2。选择其他元素：选择其他元素的系统。高达 7 的元素可以选择但建议少用，因为元素和物种大量增加计算时间和可能引发的其他问题。已经在本例中选择。注：这是没有必要选择 H
31、和 O，因为这些都是自动地包括。3. Search Mode: This selection specifies the type of species, which will be collected from the database. It is recommended to use default selections. Note: Condensed = solid substances, Aqueous Neutrals =dissolved species without charge, Aqueous Ions = dissolved ions, Gases = gaseous
32、 species without charge, Gas Ions = gaseous ions, and Liquids = liquid species.3。搜索模式：选择指定物种的类型，它将被从数据库中收集。建议使用默认的选择。注：凝结为固体物质，水中立=溶解不收费，水离子= 溶解离子，气体 =气态物种没有电荷，气体离子=气态离子，和液体 =液体的种类。4. OK: Press OK to start the search from the database.4。好：按 OK 从数据库开始搜索。5. Select Species: Usually you can select all s
33、pecies to the diagram by pressing All. In some cases, however, it is useful to remove unnecessary species from the system. This will decrease calculation time and simplify diagrams. Note: A) By pressing simultaneously Ctrl-key and clicking with the mouse it is easy to make any kind of selection. B)
34、By double clicking the species it is possible to see more information of the species. Load CUS25.IEP file to see the selected species of this example.5。树种选择：通常您可以选择的所有物种的图按所有。然而，在某些情况下，它是从系统中删除不必要的物种有用。这将减少计算时间和简化图。注：a）按下 Ctrl 键，同时用鼠标很容易做出什么样的选择点击。B）双击物种有可能看到更多的物种信息。负载 cus25.iep 文件看这个例子的选择种类。6. Temp
35、erature: The user must specify at least one temperature for the diagram. Up to four temperatures may be specified in order to draw combined diagrams, which show the effect of temperature. The temperatures 25, 50, 75 and 100 C have been selected in this example, Figs. 1 and 2.6。温度：用户必须指定至少一个温度图。高达四的温
36、度可以被指定为绘制组合图，显示温度的影响。温度 25，50，75 和 100C 已在本例中选择，无花果。1 和 2。7. Criss-Cobble: This option enables HSC to extrapolate the heat capacity function of the aqueous species if this data is not given in the database11, see Chapter 28.4.7。纵横交错的卵石：此选项使 HSC 推断水种的热容量功能如果这个数据是不是在database11 给出，见 28.4 章。8. EpH: Pres
37、s EpH to start the File Save dialog and Calculation of the diagram. You can also press File Save in order to save the data for later use without running the calculation procedure.8。弗：按弗开始保存文件对话框的图和计算。你也可以按文件保存为数据保存供以后使用无需运行的计算程序。9. Diagram: Pressing the EpH button will show the Diagram specification
38、 form, see Chapter 17.3 and Fig 2. By pressing Diagram in Fig. 2 you will see the default diagram.9。图：按弗按钮将显示图的规范形式，见 17.3 章图 2。按图在图 2 中你会看到默认的图。17.3 Eh - pH - Diagram MenuFig. 2. Default values for the Eh - pH - diagram.The EpH-diagram menu shows a summary of the chemical system specifications as w
39、ell as selected default values for the diagram. The fastest way to go forward is to accept all the default values and press Diagram for simple EpH diagrams or Combine for combined diagrams. Usually at the begining, there is no need for modifications to the default values. However, it is important to
40、 understand the meaning of these settings because they may have strong effect on the diagram. The details of the diagram menu options are explained in the following paragraphs.Eph 图菜单显示的化学系统规范总结以及选择默认值的图表。走的最快的方法是接受所有默认值，并按图简单弗图或结合组合图。通常在开始时，没有必要为默认值的修改。然而，它是理解这些设置的意义重要，因为他们可能在图上强烈的影响。图中的菜单选项的细节在下面解
41、释。1. File Open1。打开文件The EpH module can also be used as an independent application, in these cases the data for the diagram may be read from *.IEP files by pressing File Open. Normally the system specifications are automatically transferred from the system specification sheet to the diagram menu, Fig
42、. 2.Eph 模块也可以作为一个独立的应用程序，在这些情况下，图的数据可以读自*。按IEP 文件打开文件。通常的系统规格说明书由系统自动转移到关系图”菜单，如图 2 所示。The diagram specifications can be modified in the diagram menu. The selections can be saved for later use with File Save IEP selection from the menu. The IEP-files may also be edited by any text editor like Window
43、s Notepad. Please be careful as any mistake may cause unpredictable results. The calculation results may be saved to *.EPH file with File Save EpH selection and loaded back with File Open EPH selection which causes the diagram to be automatically recalculated.图规格可以在关系图”菜单修改。选择可以保存供以后使用保存文件时选择菜单。IEP文
44、件可以使用任何文本编辑器如 Windows 记事本编辑。请小心，任何错误都可能导致不可预知的结果。计算结果可以保存到文件与文件保存。弗弗的选择和装回文件打开弗选择使图自动重新计算。2. Species and DG-data workbook2。物种和 DG 数据手册The selected species and calculated DG-data based on the enthalpy, entropy and heat capacity values of the HSC database is shown on the Species sheet of the diagram w
45、orkbook, Fig. 2. The species are arranged according to elements and species type. The user can modify the DG-data as well as add or remove species in this sheet. The Species sheet makes it possible to use data and species which cannot be found in the HSC database, for example:选择的种类和计算 DG 数据基于焓，熵和热的
46、HSC 数据库容量值在图表工作簿的物种表所示，图 2。种类按要素和种类。用户可以同时添加或删除本片种DG 数据修改。物种表可以使用数据和物种而不能在 HSC 的数据库中找到，例如：A. The published Pourbaix diagrams are often based on DG-data which is given in the original papers. This DG-data can be used in the Species sheet to replace the default values based on the HSC database if nece
47、ssary. Note that these DG-values can also be calculated from the standard potential values using equation 1A.发表 Pourbaix 图往往是基于 DG 数据是原始文件。这 DG 数据可用于物种片代替默认值基于 HSC 如果必要的数据库。注意这些 DG 值也可以用公式 1 的标准电位值的计算, 1， 1 where n is the charge transferred in the cell reaction, F is the Faraday constant (23045 cal/
48、(V*mol) and E is the standard electrode potential in volts. Note: Give DG-data for the selected temperatures, usually these values are only available at 25 C.其中 n 是细胞反应的电荷转移，F 是法拉第常数（23045 卡/（V *摩尔）和 E 是伏特的标准电极电位。注：为选定的温度给 DG 数据，通常这些值在 25C.只有B. Sometimes all necessary species are not available in th
49、e HSC database. These missing species can be added to the chemical system specification if the user has the DG-values or chemical potential data for these species. The new species may be added by inserting empty row with Insert Row selection and typing formula and DG-values to this row.B.有时必要的物种没有造血干细胞库。这些失踪的物种可以被用户如果有 DG 值或化学这些物种潜在的数据添加到化学系统规范。新的物种可以被插入行的选择和输入公式和 DG 值这一行插入空行添加。The new species can be inserted into any location, but it is recommended to add the same type of species sequentially, because it makes the list easier to read and update. Note: A) Do not insert any new
