Seeking help regarding a saltwater quality issue
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This post was last edited by sunjl1981 on 2013-1-6 at 22:49. Currently, our factory uses a mixture of imported salt and domestic sea salt, and the results have been good in the past. However, recently there has been an increase in the amount of free salts in the brine; it would be better to keep the concentration around 296. Compared with another brine production system that uses only domestically produced sea salt, the specific gravity of this brine is higher. The specific details are as follows:Problematic brine: NaCl: 296–299 g/l, sulfate ions: 5.1–5.7 g/l, specific gravity: 1.19–1.21; the salt used is a mixture of domestically produced sea salt and imported sea salt.
Normal brine: NaCl: 315–320 g/l, sulfate ions: 5.1–5.7 g/l, specific gravity: 1.18–1.19; the salt used is a mixture of domestically produced sea salt and domestically produced well water salt.
Based on my personal speculation, this issue may be caused by the raw salt, which introduces anions with high molecular weights during the dissolution process. As a result, the sodium ion concentration reaches saturation levels, while the chloride ion concentration remains low. The presence of these high-molecular-weight anions increases the specific gravity of the brine. However, this is just a speculation with no basis. I would appreciate it if the teachers could help analyze the reasons why the concentration cannot be controlled properly and the specific gravity is abnormal. Thank you! Appendix: Analysis data of raw salt: Imported sea salt: Sodium chloride: 97.6%, calcium: 0.04%, magnesium: 0.01%, sulfate: 0.11%, total ammonium: 0.4 mg/100g, moisture: 1.8%, water-insoluble substances: 0.3%; appearance: pure white with fine particles. Domestic sea salt: Sodium chloride: 96.2%, calcium: 0.17%, magnesium: 0.06%, sulfate: 0.47%, total ammonium: 0.4 mg/100g, moisture: 2.4%, water-insoluble substances: 0.3%. Appearance: slightly brown in color with coarse particles. This post was last edited by nnza on 2008-2-28 13:38 ] # ， ， &
1. Mainly, the imported salt has small particles, which causes floating salt in the salt dissolving tank; as a result, the water quality does not meet the standards； 2. The normal mode of salt movement should be considered during the incorporation of the two types ； 3. Guessing that in the manufacturer’s production process, the salt dissolving tank is a classic design, with no optimization for fine salt ； 4. There are no anions; if any exist, they are sodium sulfate. The determination of sodium chloride is based on the chloride ions.
Thank you very much for the answer from the second floor. Our factory’s process is indeed not optimized for fine salt, as it has worked well in the past (for about 4 years). This problem only started appearing in the past week. (This week, there was no mention of overload, nor were any production processes changed.) ) Could you analyze again why the concentration is low while the specific gravity is high? I really can’t figure it out.
Concentration is the average value of the salt level you measure; it’s normal for the density of the saltwater surface to be high due to the presence of floating salt
Check the sodium chlorate level in the primary brine at your plant – is it quite high? Let’s talk about it after the test results come in.
1. Regarding saltwater concentration and analysis, the measurement of the concentration in g/l is affected by temperature； 2. Specific gravity measurement is generally carried out at the production site, and it is affected by sodium sulfate ； 3. Changes in the thousandth place of the specific gravity are ignored ； 4. During the analysis process, was any free salt carried away with the sample? 5. In short, under such circumstances, it is necessary to control the base flow rate in order to reduce surface salts.
Please check the post at http://bbs.hcbbs.com/viewthread.php?tid=63357&page=1 - pid313187. This post was last edited by Yuan Yuan on 2008-3-1 16:18.]
As far as I know, the analysis of sodium chloride concentration involves the measurement of chloride ions; what you mentioned about sodium ion saturation is incorrect – it is usually the anions that reach saturation； Regarding the saltwater you mentioned: For special saltwater, NaCl concentration is 296–299 g/l, sulfate concentration is 5.1–5.7 g/l, and the specific gravity ranges from 1.19 to 1.21; the salts used are a mixture of domestic sea salt and imported sea salt. For normal saltwater, NaCl concentration is 315–320 g/l, sulfate concentration is 5.1–5.7 g/l, and the specific gravity ranges from 1.18 to 1.19; the salts used are a mixture of domestic sea salt and domestic well water salt. I think there should be some potassium ions present as well, which explains why the concentration is low yet the specific gravity is high; it would be best to conduct an analysis
Thank you very much to all for your helpful answers. 1. The levels of chlorate and hypochlorite are both very low, less than 1 g/l ； 2. In our factory, for density measurement, we take a sample of the concentrated brine and bring it to the analysis laboratory for testing; generally, there is no floating salt in such samples ； 3. The saltwater concentration determined by our factory’s analysis must be calibrated using a temperature calibration coefficient ； 4. The situation at our factory has improved slightly at present, but the root cause of the problems has not yet been identified. We ask all experts to continue to provide their assistance. This post was last edited by nnza on 2008-3-3 10:43.]
:Lol :lol :lol Your domestic salt is really excellent; there’s no need to use imported salt. Take a look at the specifications of our raw salt: sodium chloride – around 95%, calcium – 0.14%, magnesium – 0.16%, sulfate ions – 0.5%, total ammonium – 0.4 mg/100g, moisture content – 1.8%. Everything else are water-insoluble substances, basically sand. We use a clarification tank process, and the brine produced from such raw salt remains clear. The salt dissolving tank needs to be cleaned three times every two months :( :L :o It’s a cylinder 5 meters high and 3.5 meters in diameter – haha, just imagine how much work that involves! Please reply to the original poster! ! ! ! . It’s clear that your brine does not meet the standards: the sulfate content should be less than 5 g/L, while the salt concentration in the brine should be between 300–310 g/L. Regarding the issue of excessive floating salts in the brine, the first thing that comes to mind is the temperature factor – at lower temperatures, more heat is lost, leading to the precipitation of crystallized salts. We are in the north, so the temperature of the saturated brine at the outlet of the salt dissolving tank must be kept 5 degrees higher than the solubility temperature of the saturated brine. This is the main reason for this problem. Another factor is the properties of the raw salt itself; a high sulfate content reduces the solubility of the brine at the same temperature, which also explains the phenomenon you mentioned. I work in the field of brine processing; feel free to discuss any issues via email at quhong*ng80@163.com
Hello, original poster: We have encountered similar problems as well, but we didn’t carry out our work with as much detail as you did; we didn’t measure the specific gravity at that time because we usually don’t test it for saline either. I think there might be two reasons: 1. Whether the mixing ratio of fine salt and coarse salt has changed. 2. Has the particle size of the fine salt changed? Additionally: The consequences of our actions were quite serious; in the end, the mixing mechanism in the Dall channel was damaged. Please be aware of this, landlord.
Solution: 1. Add a central barrel to the salt dissolving tank. 2. Add a buffer zone if possible.