CN112499659A - Method for producing calcium chloride by using magnesium and magnesium alloy dust removal waste gas - Google Patents
Method for producing calcium chloride by using magnesium and magnesium alloy dust removal waste gas Download PDFInfo
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- CN112499659A CN112499659A CN202011452118.XA CN202011452118A CN112499659A CN 112499659 A CN112499659 A CN 112499659A CN 202011452118 A CN202011452118 A CN 202011452118A CN 112499659 A CN112499659 A CN 112499659A
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- China
- Prior art keywords
- magnesium
- calcium chloride
- magnesium alloy
- waste gas
- reaction solution
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- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 title claims abstract description 36
- 239000001110 calcium chloride Substances 0.000 title claims abstract description 34
- 229910001628 calcium chloride Inorganic materials 0.000 title claims abstract description 34
- 229910000861 Mg alloy Inorganic materials 0.000 title claims abstract description 26
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 title claims abstract description 24
- 229910052749 magnesium Inorganic materials 0.000 title claims abstract description 24
- 239000011777 magnesium Substances 0.000 title claims abstract description 24
- 239000002912 waste gas Substances 0.000 title claims abstract description 21
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 13
- 239000000428 dust Substances 0.000 title claims abstract description 8
- 238000006243 chemical reaction Methods 0.000 claims abstract description 38
- 239000007788 liquid Substances 0.000 claims abstract description 23
- 235000019738 Limestone Nutrition 0.000 claims abstract description 21
- 239000006028 limestone Substances 0.000 claims abstract description 21
- 239000002253 acid Substances 0.000 claims abstract description 15
- 238000000926 separation method Methods 0.000 claims abstract description 11
- 238000010521 absorption reaction Methods 0.000 claims abstract description 10
- 239000013078 crystal Substances 0.000 claims abstract description 9
- 238000000034 method Methods 0.000 claims abstract description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 21
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims description 10
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims description 9
- 239000000292 calcium oxide Substances 0.000 claims description 9
- 238000004062 sedimentation Methods 0.000 claims description 9
- 239000000843 powder Substances 0.000 claims description 8
- 238000003825 pressing Methods 0.000 claims description 8
- 239000007921 spray Substances 0.000 claims description 8
- 239000012065 filter cake Substances 0.000 claims description 5
- 239000007789 gas Substances 0.000 claims description 5
- 238000006386 neutralization reaction Methods 0.000 claims description 4
- 238000003756 stirring Methods 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
- 238000005086 pumping Methods 0.000 claims description 2
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 abstract description 11
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 abstract description 5
- 238000001704 evaporation Methods 0.000 abstract description 4
- 235000011121 sodium hydroxide Nutrition 0.000 abstract description 4
- 238000005272 metallurgy Methods 0.000 abstract description 3
- 238000003912 environmental pollution Methods 0.000 abstract description 2
- 238000009938 salting Methods 0.000 abstract 1
- 229960002713 calcium chloride Drugs 0.000 description 22
- 239000002699 waste material Substances 0.000 description 7
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- 238000005352 clarification Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 230000003203 everyday effect Effects 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 230000001376 precipitating effect Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000005185 salting out Methods 0.000 description 2
- 238000005275 alloying Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- LLSDKQJKOVVTOJ-UHFFFAOYSA-L calcium chloride dihydrate Chemical compound O.O.[Cl-].[Cl-].[Ca+2] LLSDKQJKOVVTOJ-UHFFFAOYSA-L 0.000 description 1
- 229940052299 calcium chloride dihydrate Drugs 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/20—Halides
- C01F11/24—Chlorides
- C01F11/28—Chlorides by chlorination of alkaline-earth metal compounds
Abstract
A method for utilizing magnesium and magnesium alloy to remove dust the waste gas and produce calcium chloride, it is the technical field that magnesium and magnesium alloy waste gas recycle, can solve the existing magnesium and magnesium alloy and remove dust the waste gas after-treatment cost is high, neutralize and use sodium hydroxide or liquid caustic soda to crystallize easily problem, the invention fully absorbs the acid through increasing the absorption tower in the end of magnesium and magnesium alloy waste gas; circulating the acid liquor into an external reaction box, adding excessive limestone into the box, and fully reacting; then adjusting the pH value through a pH adjusting tank; after the reaction is finished, performing solid-liquid separation in the concentrated solution through a filter press; and evaporating and salting the separated clear liquid to obtain calcium chloride crystals. The waste gas and liquid in the production process of magnesium and magnesium alloy are fully utilized, so that the environmental pollution caused by the increase of chloride ions is reduced; the calcium chloride can be used for metallurgy and other purposes, not only has low cost, but also can bring economic value and fully utilize resources.
Description
Technical Field
The invention belongs to the technical field of magnesium and magnesium alloy waste gas recycling, and particularly relates to a method for producing calcium chloride by using magnesium and magnesium alloy dust removal waste gas.
Background
Because the flux for magnesium alloy is mainly chloride at present, a large amount of HCl waste gas can be generated in the high-temperature refining and alloying processes, the treatment is improper, the deterioration of peripheral air can be directly caused, the operation of personnel and the peripheral environment are influenced, the factory building and metal members are seriously rusted, the attractiveness of equipment and the appearance of the factory building are influenced, and the safety problem can be caused in the serious condition. The chloride waste water thus produced also becomes a problem of being difficult to handle. In addition, the environmental protection index puts forward a requirement on the treatment of chloride ions. At present, no mature technology exists. The dust removal waste liquid is neutralized by lye in the industry, but the cost is high, the waste liquid is easy to crystallize in the use process, and the effect is not ideal.
Disclosure of Invention
The invention provides a method for producing calcium chloride by using magnesium and magnesium alloy dedusting waste gas, aiming at the problems that the existing magnesium and magnesium alloy dedusting waste gas has high post-treatment cost and sodium hydroxide treatment is easy to crystallize.
The invention adopts the following technical scheme:
a method for producing calcium chloride by using magnesium and magnesium alloy dust removal waste gas comprises the following steps:
firstly, adding a spray absorption tower at the tail end of magnesium and magnesium alloy waste gas, absorbing and dissolving HCl in the waste gas into hydrochloric acid solution through spray water, pumping the hydrochloric acid solution into an external reaction box containing limestone through a circulating acid pump for reaction, then feeding the reaction solution into the spray absorption tower, and performing circulating reaction until the density of the final reaction solution is 1.1-1.2g/cm3In the circulating reaction process, the amount of limestone is supplemented according to the acid concentration;
secondly, injecting the reaction solution into a neutralization sedimentation tank, adjusting the pH value of the reaction solution to 7, stirring for 20 minutes, and carrying out sedimentation to obtain a reaction solution A;
thirdly, performing filter pressing separation on the reaction solution A through a filter press to obtain a clarified liquid containing calcium chloride and a filter cake;
fourthly, the clear liquid passes through a device with a nozzle, and is evaporated and desalted at the temperature of more than 250 ℃ to obtain calcium chloride crystals.
In the first step, the addition amount of the limestone is added according to the following proportion, and 0.5-0.55 mol of limestone is added in each mol of hydrochloric acid solution.
The method for adjusting the pH of the reaction solution in the second step is as follows: when the pH value is less than 7, adding calcium oxide powder, and adjusting the pH value to 7; when the pH is more than 7, the reaction solution is replenished and the pH is adjusted to 7.
In the third step, the filter pressing separation time of the filter press is 2-4 h.
The external reaction box containing excessive limestone is added in the first step, so that acid liquor reaction and impurity filtration can be met, and the condition that the device in the spray absorption tower is not polluted and the circulating acid pump cannot be abraded is ensured.
In the second step, the stirring time is 20min, so that the problems that the reaction is insufficient, and unreacted blocky substances enter a filter press to influence the stability of the pH value of effluent and the quality of crystallized calcium chloride can be avoided.
In the third step, the filter press can realize the separation of the calcium chloride clarified liquid, and the filter press separation time is determined according to the treatment capacity and the output of the filter press, and is generally 2-4 h.
In the fourth step, the calcium chloride crystals with different purities can be obtained by adjusting the number and the size of the nozzles through an evaporation device with the nozzles.
The invention aims to provide a method for preparing magnesium alloy by using HCl gas-containing waste liquid generated in the production process of magnesium and magnesium alloy as raw material and limestone (CaCO)3) The calcium chloride product is obtained by reacting with calcium oxide (CaO), thereby reducing the generation of waste liquid and the pollution to the environment and improving the utilization rate of resources.
The purpose of the invention is realized as follows: an absorption tower is added at the tail end of the magnesium and magnesium alloy waste gas to fully absorb acid; and (4) circulating the acid liquor into an external reaction box, and adding excessive limestone into the box to perform full reaction. Then passing through a pH adjusting pool, adding calcium oxide powder for neutralization and precipitation. After the reaction is finished, performing filter pressing separation and clarification in the concentrated solution through a filter press; evaporating and salting out the calcium chloride crystals by a device with a nozzle to obtain calcium chloride crystals.
The principle of the invention is as follows:
CaCO3+2HCl=CaCl2+H2O+CO2；
2HCl+CaO=CaCl2+H2O。
the invention has the following beneficial effects:
according to the method for producing calcium chloride by using the magnesium and magnesium alloy waste liquid, calcium chloride is obtained by reacting the magnesium and magnesium alloy waste liquid containing HCl gas with limestone, waste gas and waste liquid in the production process of magnesium and magnesium alloy are fully utilized, and environmental pollution caused by chloride ion increase is reduced; the calcium chloride can be used for metallurgy and other purposes, not only has low cost, but also can bring economic value and fully utilize resources.
Detailed Description
The invention adds an absorption tower at the tail end of the magnesium and magnesium alloy waste gas to fully absorb acid; and (4) circulating the acid liquor into an external reaction box, and adding excessive limestone into the box to perform full reaction. Then injecting the reaction solution into a neutralization sedimentation tank through a pH adjusting tank, adding calcium oxide powder when the pH is less than 7, stirring for 20 minutes, precipitating, and supplementing the reaction solution when the pH is more than 7; when the pH value is equal to 7, no adjustment is carried out to obtain a reaction solution A; performing filter pressing separation and clarification by a filter press; and (4) passing the clear liquid through an evaporation device with a nozzle, and precipitating salt to obtain calcium chloride crystals.
The volume of the spray absorption tower is 7 cubic meters, and the volume of the external reaction box is 3 cubic meters. Limestone is added according to the concentration of acid liquor, the total amount is about 10 cubic meters, 0.5 mol of limestone is added per mol of hydrochloric acid, the average acidity per hour is 0.01-0.02 mol/L, 50-100 mol of hydrochloric acid is contained in 10 cubic meters, and about 5-10 kg of limestone is added. Adding 120-240 kg each day.
Example 1
In summer, 10 tons of solution after sufficiently absorbing acid for 7 days (200 kilograms of limestone are added every day) is transferred to a pH-adjusted sedimentation tank, 40 kilograms of calcium oxide powder is added, the solution is stirred for 20 minutes, the pH value is adjusted to be 7, sedimentation is carried out, filter-pressing separation is carried out for 2 hours through a filter press to obtain 100kg of filter cakes (mainly unreacted limestone and a small amount of calcium oxide powder), 10 tons of clear liquid containing calcium chloride are obtained, and the clear liquid is placed in a clear water tank for later use. Subsequently, the clear liquid is evaporated and desalted to obtain 1.8 tons of calcium chloride crystals, and the purity of the anhydrous calcium chloride is 85%.
Example 2
In winter, 10 tons of solution after 10 days of full acid absorption is transferred into a pH-adjusted sedimentation tank (120 kilograms of limestone are added every day), 30 kilograms of calcium oxide powder is added, the mixture is stirred for 20 minutes, the pH value is adjusted to be 7, sedimentation is carried out, filter pressing separation is carried out for 2 hours through a filter press to obtain 130kg of filter cakes (mainly limestone and calcium oxide powder), 10 tons of clear liquid containing calcium chloride are obtained, and the clear liquid is placed in a clear water tank for standby. Subsequently, the clear liquid is evaporated and desalted to obtain 1.5 tons of calcium chloride crystals, and the purity of the anhydrous calcium chloride is 88%.
The purity of the calcium chloride related by the invention is far higher than the 74-77% standard of industrial calcium chloride dihydrate. Can meet the requirements of metallurgy, building and the like.
The filter cake related by the invention can also be used for producing raw materials for cement, and realizes cyclic utilization.
The calcium chloride related to the invention is evaporated for salting out, can be directly heated in a test, and is a technique known by a person skilled in the art.
Claims (4)
1. A method for producing calcium chloride by using magnesium and magnesium alloy dust removal waste gas is characterized by comprising the following steps: the method comprises the following steps:
firstly, adding a spray absorption tower at the tail end of magnesium and magnesium alloy waste gas, absorbing and dissolving HCl in the waste gas into hydrochloric acid solution through spray water, pumping the hydrochloric acid solution into an external reaction box containing limestone through a circulating acid pump for reaction, then feeding the reaction solution into the spray absorption tower, and performing circulating reaction until the density of the final reaction solution is 1.1-1.2g/cm3In the circulating reaction process, the amount of limestone is supplemented according to the acid concentration;
secondly, injecting the reaction solution into a neutralization sedimentation tank, adjusting the pH value of the reaction solution to 7, stirring for 20 minutes, and carrying out sedimentation to obtain a reaction solution A;
thirdly, performing filter pressing separation on the reaction solution A through a filter press to obtain a clarified liquid containing calcium chloride and a filter cake;
fourthly, the clear liquid passes through a device with a nozzle, and is evaporated and desalted at the temperature of more than 250 ℃ to obtain calcium chloride crystals.
2. The method for producing calcium chloride by using magnesium and magnesium alloy dedusting exhaust gas according to claim 1, which is characterized in that: in the first step, the addition amount of the limestone is added according to the following proportion, and 0.5-0.55 mol of limestone is added in each mol of hydrochloric acid solution.
3. The method for producing calcium chloride by using magnesium and magnesium alloy dedusting exhaust gas according to claim 1, which is characterized in that: the method for adjusting the pH of the reaction solution in the second step is as follows: when the pH value is less than 7, adding calcium oxide powder, and adjusting the pH value to 7; when the pH is more than 7, the reaction solution is replenished and the pH is adjusted to 7.
4. The method for producing calcium chloride by using magnesium and magnesium alloy dedusting exhaust gas according to claim 1, which is characterized in that: in the third step, the filter pressing separation time of the filter press is 2-4 h.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011452118.XA CN112499659A (en) | 2020-12-11 | 2020-12-11 | Method for producing calcium chloride by using magnesium and magnesium alloy dust removal waste gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011452118.XA CN112499659A (en) | 2020-12-11 | 2020-12-11 | Method for producing calcium chloride by using magnesium and magnesium alloy dust removal waste gas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112499659A true CN112499659A (en) | 2021-03-16 |
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| CN202011452118.XA Pending CN112499659A (en) | 2020-12-11 | 2020-12-11 | Method for producing calcium chloride by using magnesium and magnesium alloy dust removal waste gas |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100998931A (en) * | 2006-11-22 | 2007-07-18 | 刘强国 | Waste gas treatment in ranadium pentaoxide production and its comprehensive utilization technology |
| JP2013185255A (en) * | 2012-03-08 | 2013-09-19 | Nippon Sozai Kk | Method for smelting magnesium |
| CN104229854A (en) * | 2014-10-08 | 2014-12-24 | 攀枝花钢企欣宇化工有限公司 | Calcium chloride solution producing method |
| CN104445335A (en) * | 2014-12-12 | 2015-03-25 | 易科力（天津）环保科技发展有限公司 | Process and system for producing anhydrous calcium chloride by utilizing organic matter-containing waste hydrochloric acid |
-
2020
- 2020-12-11 CN CN202011452118.XA patent/CN112499659A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100998931A (en) * | 2006-11-22 | 2007-07-18 | 刘强国 | Waste gas treatment in ranadium pentaoxide production and its comprehensive utilization technology |
| JP2013185255A (en) * | 2012-03-08 | 2013-09-19 | Nippon Sozai Kk | Method for smelting magnesium |
| CN104229854A (en) * | 2014-10-08 | 2014-12-24 | 攀枝花钢企欣宇化工有限公司 | Calcium chloride solution producing method |
| CN104445335A (en) * | 2014-12-12 | 2015-03-25 | 易科力（天津）环保科技发展有限公司 | Process and system for producing anhydrous calcium chloride by utilizing organic matter-containing waste hydrochloric acid |
Non-Patent Citations (1)
| Title |
|---|
| 赵浩峰: "《镁钛合金成型加工中的物理冶金及与环境的作用》", 31 December 2008, 中国科学技术出版社 * |
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Application publication date: 20210316 |
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