CN102539329A - Method for measuring total hardness of industrial water - Google Patents

Abstract

The invention provides a method for measuring the hardness of industrial water. The method comprises the following processing steps: accurately measuring off 50mL of to-be-measured industrial water by utilizing a 50mL plastic measuring cylinder, and then injecting the 50mL of to-be-measured industrial water into a conical flask; acquiring and sequentially adding 3mL of triethanolamine solution, 3mL of ammonia buffer with the pH value of 10, 1mL of Na2S solution, 2mL of Mg<2+>-EDTA (ethylene diamine tetraacetic acid) solution and 60mg of chrome black T indicator dry powder into the conical flask, and shaking up for later use; sucking an EDTA solution to reach a scale by utilizing a syringe, holding the syringe with a left hand, holding the conical flask with a right hand so as to shake the conical flask, and dropwise adding carefully until the solution is changed from blue into red, i.e., the end point is reached; after stopping dropwise adding, observing the residual milliliter number of dropwise added reagents in the syringe; subtracting the residual milliliter number from the original 10mL to obtain the volume of consumed solution; accumulating multiples times of suction; and comparing with a known industrial water total hardness zoom table, thus looking up the numerical value of the total hardness of the industrial water. The method provided by the invention is simple to operate and low in price and can be used for rapidly measuring the total hardness of the industrial water at any time.

Description

A kind of method of testing of process water total hardness

Technical field

The present invention relates to the test chemical analysis field, be specifically related to a kind of method of testing of process water total hardness.

Background technology

The total hardness of water is meant the concentration of calcium in the water, magnesium ion.Hardness is very big to the process water influence, and a lot of industries all have technical requirement to the total hardness of water.Textile industry causes dyeing inhomogeneous with the excessive meeting of the water hardness; The excessive easy formation incrustation scale of boiler feed water hardness; Cause managing in the boiler inequality of being heated, pipe deforming or damage also possibly set off an explosion when serious; Therefore process water need often carry out Hardness Determination, and the higher water of hardness could use after need passing through softening the processing.Traditional water hardness analytical test need be set up special chemical laboratory, buys various medicines and instrument, also needs the laboratory personnel of professional training, and the expense of input is bigger.So many medium and small enterprises and miniature boiler applying unit, because of production level is low, limited fund, the practitioner is ignorant of chemical analysis knowledge, can't set up the chemical laboratory of standard.Use quality for detecting, to guarantee the safety that product quality and boiler use, need develop a kind of easy, easy operating, be suitable for the process water Estimating Total Hardness method of on-line analysis.

Summary of the invention

The object of the invention provides the method for testing of a kind of cost process water total hardness low, easy and simple to handle.

The technical scheme that adopts is:

A kind ofly measure the test kits that the process water total hardness is used, be equipped with in the test kits: the plastic centrifuge tubes of a conical flask, a disposable plastic injector, a plastic cylinder, a little plastic bottle with cover and five bracelet lids;

In the above-mentioned little plastic bottle with cover the EDTA solution that concentration is 0.02mol/L is housed;

The plastic centrifuge tube of 5 above-mentioned bracelet lids, first centrifuge tube is equipped with triethanolamine solution 3mL, and second centrifuge tube is equipped with the ammonia buffer 3mL of pH=10.0, and the 3rd centrifuge tube is equipped with Na ₂S solution 1ml, the 4th centrifuge tube is equipped with Mg ²⁺-EDTA solution 2ml, the 5th centrifuge tube are equipped with chromium black T indicator dry powder 60mg;

Above-mentioned test kits is a Hard paper box or plastic casing, and volume is 20cm * 12cm * 8cm;

Above-mentioned conical flask volume is 150mL;

An above-mentioned disposable plastic injector volume is 10mL;

An above-mentioned plastic cylinder is 50mL;

An above-mentioned little plastic bottle volume with cover is 50mL;

The plastic centrifuge tube of 5 above-mentioned bracelet lids, volume is 3mL.

A kind of assay method of process water hardness comprises following processing step:

(1) adds the reagent operation

Accurately measure 50mL process water to be measured with the 50mL plastic cylinder that has been equipped with in the box, inject the conical flask that has been equipped with in the box, get the triethanolamine solution 3mL, the ammonia buffer 3mL of pH=10, the Na that have been equipped with again ₂S solution 1mL, Mg ²⁺-EDTA solution 2mL, chromium black T indicator dry powder 60mg add in the conical flask successively, shake up, and be for use;

(2) titration operation

Getting the volume that has been equipped with in the box is the syringe of 10mL, accurately the concentration that has been equipped with of absorption be the EDTA solution of 0.02mol/L to scale, left hand is held syringe; The right hand is held conical flask and is rocked, and careful the dropping is if the EDTA consumption surpasses 10mL; Can draw once more; First quick and back slow, become blueness until solution by redness and be terminal point during dropping, stop to drip.Titration process was accomplished in 5 minutes, and temperature is not less than 15 ℃;

(3) reading is tabled look-up

After stopping to drip; Observe the interior reagent residue milliliter number that drips of syringe, using the 10mL that begins to deduct residue milliliter number is consumption liquid product, and that repeatedly draws adds up; With known process water total hardness zoom table contrast, promptly check in the numerical value of process water total hardness.

  

EDTA solution consumption liquid is long-pending to contrast zoom table with process water total hardness (mmol/L)

Consumption volume mL	Total hardness mmol/L	Consumption volume mL	Total hardness mmol/L	Consumption volume mL	Total hardness mmol/L	Consumption volume mL	Total hardness mmol/L
								0.20	0.08	2.50	1.00	5.00	2.00	8.50	3.40
0.40	0.16	2.75	1.10	5.35	2.14	9.00	3.60
								0.60	0.24	3.00	1.20	5.70	2.28	9.50	3.80
0.80	0.32	3.25	1.30	6.00	2.40	10.00	4.00
								1.00	0.40	3.50	1.40	6.35	2.54	10.50	4.20
1.25	0.50	3.75	1.50	6.70	2.68	11.00	4.40
								1.50	0.60	4.00	1.60	7.00	2.80	11.50	4.60
1.75	0.70	4.25	1.70	7.35	2.94	12.00	4.80
								2.00	0.80	4.50	1.80	7.70	3.08	14.00	5.60
2.25	0.90	4.75	1.90	8.00	3.20	16.00	6.40

The present invention utilizes reagent necessary in the product and given operation steps, the zoom table of the process water total hardness that contrast is subsidiary, and on-line determination goes out the numerical value of process water total hardness.

The invention has the advantages that:

1, the present invention is simple to operate, can draw the total hardness of process water quickly through tabling look-up, and higher utility is arranged.

2, crowd's scope of being suitable for of the present invention is wide, does not need the personnel of professional training, and the workman of workshop just can operate and monitor.Adopt the present invention to carry out on-line determination to the total hardness of process water at any time,, guarantee product quality and production safety so that grasp the situation of change of water quality.

3, raw materials used being easy to of the present invention bought, and be with low cost, is fit to produce in enormous quantities, can reduce the testing cost of process water total hardness significantly.

Claims (1)

1. the assay method of a process water hardness is characterized in that, comprises following processing step:

(1) adds the reagent operation

Accurately measure 50mL process water to be measured with the 50mL plastic cylinder that has been equipped with in the box, inject the conical flask that has been equipped with in the box, get the triethanolamine solution 3mL, the ammonia buffer 3mL of pH=10, the Na that have been equipped with again ₂S solution 1mL, Mg ²⁺-EDTA solution 2mL, chromium black T indicator dry powder 60mg add in the conical flask successively, shake up, and be for use;

(2) titration operation

Getting the volume that has been equipped with in the box is the syringe of 10mL, accurately the concentration that has been equipped with of absorption be the EDTA solution of 0.02mol/L to scale, left hand is held syringe; The right hand is held conical flask and is rocked, and careful the dropping is if the EDTA consumption surpasses 10mL; Can draw once more, become blueness until solution by redness and be terminal point, stop to drip; Titration process was accomplished in 5 minutes, and temperature is not less than 15 ℃;

(3) reading is tabled look-up

After stopping to drip; Observe the interior reagent residue milliliter number that drips of syringe, using the 10mL that begins to deduct residue milliliter number is consumption liquid product, and that repeatedly draws adds up; With known process water total hardness zoom table contrast, promptly check in the numerical value of process water total hardness.