CN114836624A - Calcium removal method for chloride or sulfate solution - Google Patents

Abstract

The invention discloses a method for removing calcium from chloride salt or sulfate solution, comprising: adding dilute alkali to the chloride salt or sulfate solution to control pH 2-5, heating to 85°C-95°C; adding additives to the solution A and additive B or only add additive B, the additive A is anhydrous sodium sulfate, and the additive B is anhydrous calcium sulfate; the solid-liquid separation is performed after concentrating 20%-30% of water by thermal insulation evaporation. When the calcium-containing solution is processed, the calcium in the solution can be efficiently removed, and the valuable metal is not lost, and the processing process is simple, safe, environmentally friendly, harmless, and low in cost.

Description

A kind of calcium removal method of chloride salt or sulfate solution

technical field

The invention relates to the technical field of chemical impurity removal, in particular to a method for removing calcium from chloride or sulfate solution.

Background technique

At present, the calcium removal method of chloride salt solution or sulfate solution containing nickel, cobalt, manganese or copper is to add sodium sulfate to remove calcium first and then add sodium fluoride to remove calcium. This method will lead to fluorine in wastewater and finished liquid. If the ions exceed the standard, the solution cannot meet the downstream quality requirements, and at the same time, it brings great difficulties to the wastewater treatment and the risk of fluorine exceeding the standard in the discharged wastewater. In addition, CN113023751A discloses a kind of method for recovering calcium from chlorinated brine. First, by controlling the pH of the solution, for the precipitation interval of different hydroxides, under different pH range conditions, Mg(OH) ₂ and Ca ( The separation of OH) ₂ , and then adopt methods such as reverse osmosis or evaporative crystallization to concentrate the solution to achieve the purpose of removing calcium in the chlorinated brine, which is complicated in process and high in cost.

SUMMARY OF THE INVENTION

In view of the deficiencies in the above-mentioned prior art, the present invention provides a method for removing calcium from chloride or sulfate solution, which is a low-cost method for removing calcium without introducing fluoride ions and subsequent requirements.

The present invention is achieved through the following technical solutions.

A method for removing calcium from chloride or sulfate solution, wherein the method comprises:

(1) adding dilute alkali to the chloride salt or sulfate solution to control pH 2-5, heating and stirring to 85 ℃-95 ℃;

(2) Add additive A and additive B or only add additive B to the solution obtained through step (1), and described additive A is anhydrous sodium sulfate, and described additive B is anhydrous calcium sulfate;

(3) Solid-liquid separation after concentrating 20%-30% of water by thermal insulation evaporation.

Further, the chloride salt solution is one of manganese chloride, cobalt chloride, nickel chloride, and cupric chloride solution; the sulfate solution is nickel sulfate, copper sulfate, manganese sulfate, and cobalt sulfate solution. a kind of.

Further, the dilute alkali concentration is 4-16%.

Further, the respective additions of the additive A and the additive B in the step (2) are 50-80g/L, 2-8g/L (that is, the addition of the additive A is that every liter of chloride or sulfate solution adds 50- 80g, the addition amount of additive B is 2-8g per liter of chloride salt or sulfate solution).

Further, in the step (2), the additive A and the additive B are added to the chloride salt solution obtained in the step (1).

Further, in the step (2), only the additive B is added to the sulfate solution obtained in the step (1).

The beneficial technical effect of the present invention is that the present invention provides a method for removing calcium from a chloride or sulfate solution. The Ca in the treated solution is less than 100 mg/L, and the calcium in the solution can be efficiently removed when the calcium-containing solution is treated. , and there is no loss of valuable metals, the treatment process is simple, safe, environmentally friendly, harmless, and low in cost.

Detailed ways

The present invention will be described in detail below with reference to specific embodiments.

Example 1

Take 1 L of manganese chloride solution, add 16% dilute alkali to adjust to pH 3.5, and continue heating and stirring for 30 minutes after stabilizing the pH, wherein the solution is heated to 85 ° C, and 80 g of anhydrous sodium sulfate is added to react for 10 minutes, and then add Anhydrous calcium sulfate 8g, continue to stir, the solution is evaporated and concentrated to 800ml by thermal insulation, filtered, and the calcium content of the solution before and after sampling is detected.

Example 2

Take 1 L of manganese chloride solution, add 8% dilute alkali to adjust to pH 5.0, and continue to heat and stir for 30 minutes after stabilizing the pH, wherein the solution is heated to 95 ° C, and 70 g of anhydrous sodium sulfate is added to react for 25 minutes. Water calcium sulfate 3g, continue to stir, the solution is evaporated and concentrated to 700ml by thermal insulation, filtered, the calcium content of the solution before and after sampling is detected, the calcium content of the front liquid is 4.38g/l, and the calcium content of the rear liquid is 54.9mg/l.

Example 3

Take 1 L of nickel sulfate solution, add 4% dilute alkali to adjust to pH 4.2, and continue to heat and stir for 30 minutes after stabilizing the pH, wherein, the solution is heated to 90 ° C, 4 g of anhydrous calcium sulfate is added, and stirring is continued. Evaporate and concentrate to 750ml, filter, and take samples to detect the calcium in the solution before and after.

Example 4

Take 1 L of manganese sulfate solution, add 4% dilute alkali to adjust to pH 4.8, and continue to heat and stir for 30 minutes after stabilizing the pH, wherein the solution is heated to 87 ° C, 2 g of anhydrous calcium sulfate is added, and stirring is continued. Evaporate and concentrate to 700ml, filter, take samples to detect the calcium in the solution before and after, the calcium in the former solution is 3.11g/l, and the calcium in the latter solution is 78.9mg/l.

Example 5

Take 1 L of copper sulfate solution, add 16% dilute alkali to adjust to pH 2.0, stabilize the pH and continue to heat and stir for 30 minutes, wherein the solution is heated to 92 ° C, add 5 g of anhydrous calcium sulfate, continue to stir, the solution is kept warm Evaporate and concentrate to 800ml, filter, take samples to detect the calcium in the solution before and after, the calcium in the former solution is 1.95g/l, and the calcium in the latter solution is 30.9mg/l.

Example 6

Take 1 L of cobalt chloride solution, add 8% dilute alkali to adjust to pH 3.7, and continue to heat and stir for 30 minutes after stabilizing the pH, wherein the solution is heated to 95 ° C, and 50 g of anhydrous sodium sulfate is added to react for 15 minutes, and then add Anhydrous calcium sulfate 3g, continue to stir, the solution is evaporated and concentrated to 700ml by heat preservation, filtered, sampled to detect the calcium in the solution before and after, the calcium in the front liquid is 2.63g/l, and the calcium in the rear liquid is 30.9mg/l.

The above descriptions are only preferred embodiments of the present invention, and do not limit the invention. It should be pointed out that for those of ordinary skill in the art, under the technical inspiration provided by the present invention, other equivalent improvements can also be made, all of which can achieve the purpose of the present invention and should be regarded as the protection scope of the present invention.

Claims (6)

1. A method for decalcifying a chloride or sulfate solution, said method comprising:

(1) adding dilute alkali into the chloride or sulfate solution to control the pH value of 2-5, and heating and stirring to 85-95 ℃;

(2) adding an additive A and an additive B into the solution obtained in the step (1) or only adding the additive B, wherein the additive A is anhydrous sodium sulfate, and the additive B is anhydrous calcium sulfate;

(3) concentrating 20-30% water by heat preservation and evaporation, and then carrying out solid-liquid separation.

2. The method of claim 1, wherein the chloride solution is one of manganese chloride, cobalt chloride, nickel chloride and copper chloride; the sulfate solution is one of nickel sulfate, copper sulfate, manganese sulfate and cobalt sulfate solution.

3. The method of claim 1, wherein the dilute alkali concentration is 4-16%.

4. The method for removing calcium from a chloride or sulfate solution according to claim 1, wherein the additive A and the additive B are added in an amount of 50-80g/L and 2-8g/L respectively in step (2).

5. The method for removing calcium from a chloride or sulfate solution according to claim 1, wherein the step (2) comprises adding the additive A and the additive B to the chloride solution obtained in the step (1) by the following steps: adding the additive A to react for 10-30min, and then adding the additive B.

6. The method for removing calcium from a chloride or sulfate solution according to claim 1, wherein the step (2) is performed by adding only the additive B to the sulfate solution obtained in the step (1).