1、Designation: D4328 08 (Reapproved 2013)D4328 18Standard Practice forCalculation of Supersaturation of Barium Sulfate, StrontiumSulfate, and Calcium Sulfate Dihydrate (Gypsum) inBrackish Water, Seawater, and Brines1This standard is issued under the fixed designation D4328; the number immediately foll
2、owing the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope Scope*1.1 This prac
3、tice covers the calculation of supersaturation of barium sulfate, strontium sulfate, and calcium sulfate dihydrate(gypsum) in brackish water, seawater, and brines in which barium, strontium, and calcium ions either coexist or exist individuallyin solution in the presence of sulfate ions.1.2 This pra
4、ctice is not applicable for calculating calcium sulfate dihydrate supersaturation if the temperatures of saline watersunder investigation exceed 95C. At temperatures above 95C, hemianhydrate and anhydrite would be major insoluble forms.1.3 The values stated in SI units are to be regarded as standard
5、. No other units of measurement are included in this standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety safety, health, and healthenvironmental practi
6、ces and determine theapplicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Reco
7、mmendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D511 Test Methods for Calcium and Magnesium In WaterD512 Test Methods for Chloride Ion In WaterD513 Test Methods for Total and Dissolved Carbon Dioxide in WaterD51
8、6 Test Method for Sulfate Ion in WaterD1129 Terminology Relating to WaterD3352 Test Method for Strontium Ion in Brackish Water, Seawater, and BrinesD3370 Practices for Sampling Water from Closed ConduitsD3561 Test Method for Lithium, Potassium, and Sodium Ions in Brackish Water, Seawater, and Brines
9、 by Atomic AbsorptionSpectrophotometryD3651 Test Method for Barium in Brackish Water, Seawater, and BrinesD3986 Test Method for Barium in Brines, Seawater, and Brackish Water by Direct-Current Argon Plasma Atomic EmissionSpectroscopy3. Terminology3.1 DefinitionsDefinitions: For definitions of terms
10、used in this practice, refer to Terminology D1129.3.1.1 For definitions of terms used in this standard, refer to Terminology D1129.4. Significance and Use4.1 This practice covers the mathematical calculation of the supersaturation of three principal sulfate scaling compounds foundin industrial opera
11、tions. Application of this standard practice to the prediction of scale formation in a given system, however,1 This practice is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.05 on Inorganic Constituents in Water.Current edition approved Ju
12、ne 1, 2013May 1, 2018. Published July 2013May 2018. Originally approved in 1984. Last previous edition approved in 20082013 asD4328 08.D4328 08 (2013). DOI: 10.1520/D4328-08R13.10.1520/D4328-18.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at se
13、rviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version
14、. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section
15、 appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1requires experience. The calculations tell the user if a water, or mixture of waters, is in a scaling mode. Whether or not scale willin fact form, how
16、 quickly it will form, where it will form, in what quantities, and what composition are subject to factors beyondthe scope of this practice. However, based on how supersaturated a given water or mixture of waters is, an objective evaluationof the relative likelihood of scale formation can be made.NO
17、TE 1There are several personal computer (PC) type programs that are both available commercially and publicly that will perform thesecalculations.5. Procedure5.1 Collect water samples for compositional analysis in accordance with Practices D3370.5.2 Determine the calcium and magnesium concentrations
18、in accordance with Test Methods D511.5.3 Determine the barium concentration in accordance with Test Methods D3651 or D3986.5.4 Determine the strontium concentration in accordance with Test Method D3352.5.5 Determine sodium and potassium concentrations in accordance with Test Method D3561.5.6 Determi
19、ne sulfate ion concentration in accordance with Test Method D516.5.7 Determine chloride ion concentration in accordance with Test Methods D512.5.8 Determine carbonate and bicarbonate ion concentrations in accordance with Test Methods D513.5.9 Determine the concentrations of all other major inorganic
20、 constituents that may be present in the water under investigationin accordance with appropriate test methods in Annual Book of ASTM Standards, Vols 11.01 and 11.02.5.10 Determine temperature and pressure of the water system under investigation.6. Calculation of Ionic Strength6.1 Calculate the ionic
21、 strength of the water under investigation as follows: 512(CiZi2 (1)where: = ionic strength,Ci = molal concentration of each ion in solution, andZi = charge number of ion, i.7. Calculation of Barium Sulfate Supersaturation (Refer to Appendix X1)7.1 Calculate barium sulfate solubility in the water un
22、der investigation, using the equation as follows:S 5=X 214K 2X!/2 (2)where:S = solubility, moles of solute per kilogram of water corrected for the common ion effect,K = solubility product constant (molal) at the ionic strength, temperature and pressure of the water under investigation. ForBaSO4 refe
23、r to Appendix X2, andX = molal excess of soluble common ion.7.2 Calculate the amount of barium sulfate, moles per kilogram of water, in the sample based on the lesser of the barium orsulfate ion concentration.7.3 If the amount of BaSO4 in the sample (7.2) is less than its calculated solubility (7.1)
24、, the water in question is undersaturatedwith respect to BaSO4. If the amount of BaSO4 present is greater than its solubility, the water is supersaturated with respect toBaSO4. Calculate the amount of supersaturation as the difference between the two values:supersaturation5concentration2solubility (
25、3)NOTE 2Supersaturation may also be calculated directly from the equation (1).3Ba11#2y!SO45#2y!5K (4)where:Ba2+ = concentration of barium, molal,SO42 = concentration of sulfate, molal,3 The boldfaced numbers in parentheses refer to a list of references at the end of this standard.D4328 182y = excess
26、 (supersaturation) of BaSO4, molal, andK = solubility product constant (molal) of BaSO4 at test conditions.The value X may then be determined from the quadratic equation (see Appendix X1):X 52B6=B224AC2A (5)Report BaSO4 supersaturation in molal terms of the weight of BaSO4 per volume of water, mg/L.
27、BaSO4 supersaturation,mg/L5BaSO4,molal2!310332333S10003DTDS100011000DBaSO4 supersaturation,mg/L (6)5BaSO4,molal2!310332333S10003DTDS100011000Dwhere:where:D = sample density.8. Calculation of Strontium Sulfate Supersaturation (Refer to Appendix X1)8.1 Calculate strontium sulfate solubility using the
28、same steps described for BaSO4 (Section 7), but substituting the appropriatevalues for SrSO4 in Eq 2 (refer to Appendix X3 or Appendix X4).NOTE 3If barium sulfate supersaturation exists, the amount of sulfate available for strontium sulfate will be less by the amount of sulfate equivalentto the calc
29、ulated BaSO4 supersaturation.NOTE 4If carbonate ions are present, strontium carbonate may precipitate. The amount of strontium may then be corrected by that required forstrontium carbonate precipitation prior to the calculation of SrSO4 solubility (2). Practically speaking, however, due to the extre
30、mely low solubility ofSrCO3, this correction may usually be omitted.8.2 Calculate the amount of strontium sulfate moles per kilogram water in the sample based on the lesser of the strontium orremaining sulfate ion concentration.8.3 If the amount of SrSO4 in the sample (8.2) is less than its calculat
31、ed solubility (8.1), the water in question is undersaturatedwith respect to SrSO4. If the amount of SrSO4 present is greater than its solubility, the water is supersaturated with respect toSrSO4. Calculate the amount of supersaturation, moles per kilogram water by difference (Eq 3), or by substituti
32、ng appropriate datain Eq 4 (Note 2).8.3.1 Report SrSO4 supersaturation in terms of the weight of SrSO4 per volume of water as follows:SrSO4 supersaturation mgL5SrSO4,molal!310331843S 10003DTDS100011000DSrSO4 supersaturation mgL (7)5SrSO4,molal!310331843S 10003DTDS100011000D9. Calculation of Calcium
33、Sulfate Supersaturation (Refer to Appendix X1)9.1 Calculate calcium sulfate solubility using the same steps described for BaSO4 (Section 7), but substituting the appropriatevalues for CaSO4 in Eq 2 (refer to Appendix X5).9.2 Calculate the amount of calcium sulfate moles per kilogram in the sample ba
34、sed on the lesser of the calcium or remainingsulfate ion.9.3 If the amount of CaSO4 in the sample (9.2) is less than its calculated solubility (9.1), the water in question is undersaturatedwith respect to CaSO4. If the amount of CaSO4 present is greater than its solubility, the water is supersaturat
35、ed with respect toCaSO4. Calculate the amount of supersaturation moles per kilogram by difference (Eq 3) or by substituting appropriate data in Eq4 (Note 2).D4328 1839.3.1 Report CaSO4 supersaturation in terms of the weight of CaSO42H2O (gypsum) per volume of water after convertingmoles per data obt
36、ained above to mg/L as follows:CaSO2H2Osupersaturation,mg/L (8)5CaSO42H2O2,moles/kg3172.1731033D10. Keywords10.1 barium sulfate; brines; calcium sulfate dihydrate; strontium sulfateAPPENDIXES(Nonmandatory Information)X1. SAMPLE CALCULATION OF BaSO4 SUPERSATURATION AT 95CAnalysis of Water Ionic Stren
37、gthComponent Ions mg/L molesMoles per litre Litre A molal MolalA Concentration Z 2 = 12 ,Z,2(Section 6)Na 27 120 1.180 1.214 1 1.214Ca 10 890 0.272 0.280 4 1.120Mg 1679 0.69 0.071 4 0.284Ba 6.4 0.000044 4.52 10 5 4 0.001Sr 444 0.00506 521.42 10 5 4 0.021Cl 64 870 1.830 1.883 1 1.883SO4 1210 0.012596
38、 1296.14 10 5 4 0.052HCO3 317 0.005 0.005 1 0.005TDS = 106 536 Total ionic strength = 2.29Density = 1.078 g/ml KBaSO4 at 95 (Appendix X1) = 83.22 10 9AConvert moles/Lto molal5moles/L3 1000sSp gr31000d2 TDS1000Convert moles/Lto molal5moles/L3 1000sSp gr31000d2 TDS10005moles/L3 100010782106.55moles/L3
39、1.0295moles/L3 100010782106.55moles/L31.029X1.1 BaSO4 Solubility (Refer to 7.1):S 5=X214K 2X!/2where:X = molal excess of common ion (in this case SO4),X = (1296.14 105) (4.52 105)= 1291.62 1054K = 4(83.22 109) = 332.88 109, or 3328.8 1010S = =1291.6231025!213328.8310210! (1291.62 105)/2Solubility S
40、= 0.644 105 molalD4328 184X1.2 BaSO4 Present (Refer to 7.2):X1.2.1 Ba present = 4.52 105 molalX1.2.2 SO4 present = 1296.14 105 molalX1.2.3 Based on lower value (Ba), BaSO4 present = 4.52 105 molalD4328 185X1.3 Amount of BaSO4 Supersaturation (Refer to 7.3):X1.3.1 BaSO4 present based on Ba2+ = 4.52 1
41、05 molalX1.3.2 Calculated BaSO4 solubility, S = 0.64 105 molalX1.3.3 BaSO4 excess; that is, supersaturation = 3.88 105 molal; or 8.8 mg/L of sampleD4328 186X1.4 Useful Information: Useful Information:MolMol WeightEquivalentWeightGravimetric ConversionFactorsBa 137.33 68.66 Ba 1.6995 = BaSO4Ca 40.08
42、20.04 Ca 3.3967 = CaSO4Sr 87.62 43.81 Sr 2.0963 = SrSO4SO4 96.06 48.03BaSO4 233.39 116.70 SO4 2.4296 = BaSO4CaSO4 136.14 68.07 SO4 1.4172 = CaSO4CaSO42H2O 172.14 86.07 SO4 1.9121 = SrSO4SrSO4 183.68 91.84X1.5 The amount of supersaturation (excess BaSO4) may also be calculated directly using the expr
43、ession (Eq 4):Ba11#2X! SO45#2X!5K BaSO4D4328 187X1.5.1 Using the molal values from the water analyis above this becomes:4.5231025#2X! 1296.1431025#2X!5832.2310210Multiplying:5858.55310210!21300.6631025!4.5231025#2X! 1296.1431025#2X!5832.2310210Multiplying:5858.55310210!21300.6631025!X1X25832.2310210
44、Combining:X221300.6631025!X15026.3531021050X1.5.2 Substituting the above coefficients of X in the quadratic equation:X 52b6=b224ac2aand solving, X = 3.88 105 molal; or 8.8 mg/L of sample.X2. SOLUBILITY DATA FOR BaSO4NaClH2O SYSTEMS (3)SolutionIonic Strength,Solubility Product Constant, K (Molal)25C
45、35C 50C 65C 80C 95C0.1 1.54 109 2.00 109 2.70 109 3.34 109 3.76 10 3.97 1090.2 2.70 3.36 4.76 5.93 7.06 7.740.4 4.49 5.63 7.92 10.61 13.69 16.130.6 6.08 7.74 11.03 15.38 20.45 24.970.8 7.74 9.60 13.69 20.16 26.57 33.491.0 9.22 11.24 16.38 24.02 32.76 42.021.5 12.54 15.38 22.20 32.40 44.94 62.002.0 1
46、5.63 19.04 27.23 39.60 56.17 78.962.5 18.23 21.90 31.33 44.94 63.50 93.643.0 20.74 24.65 34.97 49.73 70.23 107.573.5 23.41 27.56 38.81 53.82 76.73 120.414.0 25.92 30.63 42.44 58.08 82.94 132.504.5 28.56 34.23 45.80 63.00 89.40 144.40X3. SOLUBILITY PRODUCT DATA FOR SrSO42NaClH2O SYSTEMS (4)Solution I
47、onic A Solubility Product Constant, K (Molal)Strength, 40C (104F) 71C (160F)0.1 0.250 105 0.160 1050.2 0.390 0.2500.3 0.505 0.3450.4 0.617 0.4400.5 0.723 0.5180.75 1.02 0.7851.0 1.26 1.041.25 1.48 1.251.5 1.68 1.411.75 1.86 1.572.0 2.00 1.682.25 2.09 1.762.5 2.14 1.812.75 2.16 1.843.0 2.17 1.863.25
48、2.19 1.873.50 2.20 1.88A The above table may be used to interpolate the solubility product (K) for SrSO4 in brines at 0 psig. The interpolated values can be substituted in Eq 2 (Section 7) forestimating the solubility (S) of SrSO4. For more precise K values at temperatures up to 300F (149C) and pres
49、sures up to 3000 psig add SI unit, refer to Appendix X4.D4328 188X4. EQUATION FOR CALCULATING SrSO4 SOLUBILITY (5)X4.1 Experimental SrSO4 solubility data have been reduced to the following regression equation for calculating the solubilityproduct constant (K) at various solution ionic strengths over a temperature range of 100 to 300F (38 to 149C) and pressures upto 3000 psig. The equation is adaptable
