CN105842236A - Method for measuring sodium chloride content in sintering synergist through silver nitrate titration - Google Patents

Abstract

The invention discloses a method for measuring a sodium chloride content in a sintering synergist through silver nitrate titration. The method comprises the following steps: 1) adding the sintering synergist in a neutral or weak basic solution while performing stirring, and carrying out filtration to remove precipitation for obtaining a filtrate containing chloride ions; 2) adding a potassium chromate indicator into the filtrate, and performing titration with a silver nitrate standard titration solution till a white precipitation is separated and the solution turns brick-red and the titration end point is achieved; and 3) calculating the chloride ion content according to the consumption of silver nitrate when the titration end point is reached. The method is simple in steps and low in technical requirements, and the content of sodium chloride in the sintering synergist can be fast, accurately, efficiently measured.

Description

A kind of method of sodium chloride content in silver nitrate titration volumetric determination sintering synergistic agent

Technical field

The present invention relates to the assay method of sodium chloride content, specifically, relate to surveying with silver nitrate titration volumetric method Determine the assay method of sodium chloride content in sintering synergistic agent.

Background technology

Sintering synergistic agent is a kind of change by multiple non-energy Inorganic Chemicals formula combination in proportion Learn additive.Its Main Function is in the case of SINTERING PRODUCTION condition is constant, improves sintering velocity and sintering deposit Intensity, reduces pulverization rate, improves into mineral nitrogen amount, reaches volume increase, consumption reduction, the warp of each side such as environmental protection Ji benefit and social benefit.Usually it is applied to Iron concentrate, ferronickel breeze and the sintering of other non-ferrous metal, smelting Refining.

Sintering synergistic agent exists multiple miscellaneous point, such as sodium carbonate, sodium chloride etc., at present for the survey of these compositions Surely there is no simple, fast, standard operation method accurately.For the mensuration of sodium chloride, prior art is logical Cross the quality of the content acquisition sodium chloride measuring chloride ion.Chloride ion content in the most general mensuration brown iron oxide Method be distillation and colour comparison method, fluorescent spectrometry, turbidimetry, spectrophotography, potentiometric titration, ion Chromatographys etc., wherein distillation and colour comparison method testing efficiency is the lowest, even skilled operator also could only in one day Measure several sample, it is impossible to meet industry needs；Fluorescent spectrometry needs corresponding brown iron oxide chlorine when measuring Ion standard specimen, there is no this type of production marketing in the market；The chromatography of ions need by distillation by chloride with Hydrogen chloride isolated in form out, then selects suitable method to be measured, and general distilling apparatus is the most multiple Miscellaneous, condition controls the strictest, and distillation not exclusively also can affect measurement result below；Constant-current titration Method titration end-point judges that terminal costs is high, and this type of process determining existing is sour molten chloride ion, operation step Rapid complicated.

Goal of the invention

For the defect of prior art, the invention provides a kind of with silver nitrate titration volumetric determination adglutinate synergism In agent sodium chloride content method, the method have easy and simple to handle, use cost is low, accurate and the most excellent Point, it is possible to sodium chloride content in low cost, accurately mensuration sintering synergistic agent.

Specifically, the present invention is achieved through the following technical solutions:

In a kind of silver nitrate titration volumetric determination sintering synergistic agent, the method for sodium chloride content, comprises the steps: 1) sintering synergistic agent is joined and neutrality or weakly alkaline solution filter off after stirring precipitation, obtain chloride ion-containing Filtrate；2) in filtrate, drip Neutral potassium chromate indicator, be titrated to separate out white with silver nitrate standard titration solution Precipitation becomes brick-red as titration end-point；3) according to the consumption calculating chloride ion of silver nitrate during titration end-point Content.

By said method, owing to the dissolubility of silver chloride is less than siliver chromate, and what silver chloride and siliver chromate precipitated First colouring discrimination extremely notable (white-brick-red), therefore separate out silver nitride precipitation, wait silver chloride in solution After quantitative deposition, the silver nitrate of excess reacts with chromate, generates bolarious siliver chromate precipitation, i.e. reaches to drip Determine terminal.Utilize the color distortion of the two Precipitation, can accurately judge titration end-point, thus accurate recording nitre The consumption of acid silver, carries out data process by the silver nitrate consumption that itself and blank experiment titrate and i.e. can get adglutinate synergism Sodium chloride content in agent.

Wherein, in the above-mentioned methods, as long as neutrality used or alkaline solution make chloride ion to dissolve, and In sintering synergistic agent, other composition is insoluble in wherein, it is preferred that neutral solution is water, and weakly alkaline solution is Sodium carbonate liquor or ammonia spirit.

Wherein, the consumption of solution can determine according to the type of solution, it is however generally that, increase relative to 1g sintering Sodium chloride content in effect agent, neutral or alkaline solution consumption is 80-150ml.

In the above-mentioned methods, it is salt of weak acid, in an acidic solution chromate and hydrion due to Neutral potassium chromate used Cause it can not be immediately generated siliver chromate precipitation when equivalent point in conjunction with the concentration that can reduce chromate；And at highly basic Property anions and hydroxide ion can produce silver oxide precipitates；In order to avoid going out of the problems referred to above as far as possible Existing, present invention additionally comprises by using acid-base modifier set-up procedure 1) filtrate of gained chloride ion-containing is to pH The step of value 6.5-10.5 (alkalescence).

Generally, acid-base modifier used is sodium bicarbonate and nitric acid.

Applicant have extensively studied the content of chloride ion and silver nitrate solution concentration to brick-red siliver chromate occur The impact of precipitation generation time, it is preferred that the concentration of silver nitrate standard titration solution is 0.1moL/L.At this Under concentration, extend the response time generating silver chloride as far as possible, accurately to determine titration end-point.

In order to reduce the impact of experimental error as far as possible, the most also can design blank solution, measure steaming Distilled water makees blank.Add the potassium chromate solution with said determination process equivalent, under constantly shake, use silver nitrate Standard solution is titrated to brick-red precipitation and has just appeared as terminal, and the consumption of record silver nitrate now, at meter This partial amounts is deducted when calculating chloride ion content.

The experimental technique of the present invention, has a following technological progress:

1) quickly, efficiently: this method, with water or weakly alkaline solution dissolved samples, separates through filtering, and adds Just can titrate after indicator, operating procedure is very simple, measures quickly, it is adaptable to large quantities of examinations in the middle of producing The quick mensuration of sample.

2) accurate, stable: to use silver nitrate titration to measure, and have selected corresponding efficient indicator, terminal Variable color is fairly obvious, and titration end-point is easily observed, and result is stable and accurate.

Detailed description of the invention

In following enforcement, applicant provide the some of the present invention and implement, be merely to illustrate the bright side of this law The principle of method.Use alternate manner, such as, buy the silver nitrate standard titration solution with certain concentration from market Deng, or the quality of adjustment sample, still belong to protection scope of the present invention.

The assay method of the present invention, reagent used is as follows:

1) sodium chloride (solid, benchmark), commercially available purchase；

2) Neutral potassium chromate indicator (saturated), commercially available purchase；

3) silver nitrate standard titration solution concentration is 0.10000mol/L, as follows preparation: weigh 17.5000g Silver nitrate, adds 100mL water so that it is is diluted with water to 1000mL after dissolving, shakes up.Solution is stored in brown In Ping, its concentration is about 0.10000moL/L.Then it is demarcated: weigh 0.1169g standard reagent Sodium chloride (550 DEG C of calcinations to constant weight before using), is dissolved in 70mL water, adds 3 Neutral potassium chromate indicators, It is titrated to separate out white precipitate with silver nitrate standard titration solution become brick-red and be titration end-point.

$X\left({\mathrm{AgNO}}_3\right)=\frac{m}{V\×{10}^{-3}\×M}$

C(AgNO₃): silver nitrate standard titration solution concentration, moL/L.

M: weigh the quality of sodium chloride, g.

V: consume the volume of silver nitrate solution, mL.

The molal weight of M: sodium chloride, 58.44g/moL.

The detailed process of assay method of the present invention is as follows:

Weigh sintering synergistic agent sample 0.5000g to be placed in 250mL beaker, add 50mL water and make sample dissolution, Stir 5min with Glass rod simultaneously, filter at (quantitative Medium speed filter paper cushioning angle), with water washing and precipitating 7 times, discard Precipitation, obtains the filtrate of chloride ion-containing.

Filtrate is accessed in 400mL beaker, regulate pH value 6.5-10.5 with sodium bicarbonate and nitric acid, drip 3 Drip Neutral potassium chromate indicator, be titrated to separate out white precipitate with silver nitrate standard titration solution and become brick-red, be Titration end-point, the silver nitrate standard titration solution volume V that record titration is consumed.

Distilled water with filtrate equal volume is accessed in 400mL beaker, regulates PH with sodium bicarbonate and nitric acid Value 6.5-10.5, drips 3 Neutral potassium chromate indicators, is titrated to separate out brick red with silver nitrate standard titration solution Color precipitates, and is titration end-point, the silver nitrate standard titration solution volume V that record titration is consumed₀

The mass content of sodium chloride in calculating sintering synergistic agent according to the following equation:

$W(\%)=\frac{C\×(V-V_0)\×M}{m\×1000}\×100$

In formula: C: silver nitrate standard titration solution concentration, moL/L

V: the silver nitrate standard titration solution volume that titration is consumed, mL

V₀: the volume of the silver nitrate standard titration solution that titration blank consumes, mL

M: sample mass, g

The molal weight of M: sodium chloride, 58.44g/moL

Based on given sample, use different NaCl mark liquid addition (%), weigh the inventive method The response rate, as shown in table 1 below:

Table 1: the response rate that mark-on reclaims

As can be seen from the above table, when using the mensuration that the method for the present invention is sintered sodium chloride content in synergist, The response rate that mark-on reclaims is the highest, and the method is feasible；The above results also shows simultaneously, the method pair of the present invention Maintain relatively stable measurement result in the change of sodium chloride content widely, illustrate that the method for the present invention can be accurate Measure sodium chloride content in sintering synergistic agent.

Claims (5)

1. the method for sodium chloride content in a silver nitrate titration volumetric determination sintering synergistic agent, it is characterised in that bag Include following step: 1) join sintering synergistic agent neutrality or weakly alkaline solution filter off after stirring and precipitate, Filtrate to chloride ion-containing；2) in filtrate, drip Neutral potassium chromate indicator, drip with silver nitrate standard titration solution The fixed white precipitate that extremely separates out becomes brick-red as titration end-point；3) according to the consumption of silver nitrate during titration end-point Amount calculates chloride ion content.

Method the most according to claim 1, it is characterised in that relative to 1g sintering synergistic agent, neutral or alkaline solution Consumption be 80-150ml.

Method the most according to claim 1, it is characterised in that neutral solution is water.

Method the most according to claim 1, it is characterised in that also include set-up procedure 1) filtrate of gained chloride ion-containing Step to pH value 6.5-10.5.

Method the most according to claim 1, it is characterised in that the concentration of silver nitrate standard titration solution used is 0.1moL/L。