The object of this thesis is to attempt to solve a few of the many problems of assaying. Each problem is handled separately from, and independently of the others --page 1

Chase, James Howard

English

Missouri University of Science and Technology (Missouri S&T): Scholars' Mine

Scholars' Mine Bachelors Theses Student Theses and Dissertations 1912 Some assay problems James Howard Chase Follow this and additional works at: https://scholarsmine.mst.edu/bachelors_theses  Part of the Physical Sciences and Mathematics Commons Department: Recommended Citation Chase, James Howard, "Some assay problems" (1912). Bachelors Theses. 30. https://scholarsmine.mst.edu/bachelors_theses/30 This Thesis - Open Access is brought to you for free and open access by Scholars' Mine. It has been accepted for inclusion in Bachelors Theses by an authorized administrator of Scholars' Mine. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact scholarsmine@mst.edu. S 0 MEA S SAY PRO B L ~ IT S-by-James Howard Chase...... : ..:""l -.ATHE SSubmitted to the faculty of theSCHOOL OF MllIES AnD METAI-ALURGY OF THE UNIVERSITY OF MISSOURIin partial fulfillment of the work required for theDEGREE OFBACHBI,OR OF SCIENCE IN GE1TERAL SCIENCEio11a t 1'.[0.1912.Appro,ved by ---~rSjM:rl!Metanurgy14235~able of Contents.Page.Objeot of thesis - - - - - - - - - - - - - - - - - - 1Problem I .2ffeot of the silicate degree on thefua i b iIi ty o;f a ~3say s 1aga - - - - - - - - - 1Temperature at w'hj oh sodium silioa.te will fuee -1Table I 2Melting point of various sodium ba~1io sili.cates-2Table II. 3Amount of 8i02 necessary to saturatesodium silicates at different temperatures -3Table III. - - - - - - - - - - - - - - - - -4Problem II.Amount Ag held in filtrate from Kef( solution - -5!~thods of precipitating Ag from solution - 5Table IV. - - - - - - - - - - - - - - - - - 5l1robler!l III.Amount Ag held up by matte - -Charges used - - - -Table v.Conclusions - -- - - - -6- - - - - - - ·7- - - - - - 8- - - - - - 9The object of this thesis is to attempt to solvaa few of the many problems of assaying. ~ach problem ishandled separately froffi)and independently of the others.The effect of the silicate degree on the fusibilityof assay slags was the first subject studied. Accordingto Fulton, the higher the silicate degree, the more in-fusible is the mixture. Also) a "1ixture containing anumber of bases is more readily fusible than one of fewbases. The purpose of this experiment. then.is to findout the fusibility and some of the physical proDerties ofassay slags.The first step was to find at what temperaturesthe various sodium silioates became sUffioiently liquidto pour. Pure, finely ground 5102 and n~o3 were used.These two constituents were thoroughly mixed in differentratios and placed in a muffle at a temperature of about800· C. The temperature was then slowly raised and eachoharge taken out and poured when it had become sufficientlyliquid. The temperature at which the fusion of eachcharge started, the tenperature at the time of taking outeaoh charge, and the physioal condition of the slag aspoured and after cooling were noted. Table :L oontainsthe results of this Bartee of experiments.-1-Table I.gg_.gramsI gramslsilioate t 1temp.at temp. need-j condi- colorSi02 IN82J03f degree whichfus- cd to makei tion of of slaI jo Q e.',,( la 0 b4 ion starts charge___J slag as afterR l(.. liguid poured: coolin25 j 10 Is to 1 did not become liquid up to 11400.!~, i I\ I ~ 125 15 I 5 to 1 1I j, t~ ~-_._--_._--;- ~! 6 . ~25 20 j4 to 1 11000. 11200. Iviscous I green1~ Iv~ 'l~ I -"'.__._--.- I ! ...i• 1050C. I25 25 tri- 10308. viscous greenilicate !;11 "to I , I• • ! l25 30 bi- 990C .. 10050. j viscous , greenI 1ailicate ;! tI • • I25 35 n 9700. 9800. I viscous greenI\ itrans-II! !parent~• • ! i25 40 n 9500, 968C- viscous i n, I, I1..' I-• 915·0. I ViBOOUB~hi te25 40 --- 900e •~ itreousThe seoond step of the first problem was to findthe effeot on the melting point of a sodium silicate causedby the addition of CaD, FeG, A120~ or PbO in known amounts.A sodium silioate oontaining 10 grams Si02 and20 grams N82C03 was used beoause of its reasonably lowmelting point.-2-The CaO, PbO, FeG t and Al n 03 were all pure.t:.,The results follow in Table II.Table II.t-! fusiblEti at I1125f 12901111--------fllSion)I'liX-!grams gra."ls IgraI'ls 3ilicate ~ condi- 8ppear-Si02 lTs2C03 base degree began }ture ; tion of ance ofI at jliquid j slag as~ slag.;~ at poured oj;+,I10 I 20 tto FeO singulo 9750 '11250 tStiakty I Black-viI 0 Ii ; i ! reous, ,II ii Isesqui 112000 i10 20 I 5 FeO 11250tn b1ack-t ! 1$18s8YI 110 i -r-" ;112750 :10 20 CaO singulo 12000 ! tT ~ greenishi i I ! 1 white;, I +-t if k 112900 t10I20 J 5 'JaO sesqui 1200C tf Igreenishwhite-10 20 10 PbO sesqui 1000e 1137C n yellow,I , !111750 !10 20 5 !'bO bi- 1080C I n greenishsilicate I t yellowI lI 110 sUb- J i ! f10 20 A12017 122501 in- ~ -- t -------I I (' sUicate_10_1 2_°__15 A1204_s_i_ngu_"_+The object of the last part of this problem wasto find how much 8i02 it takes to saturate a sodium silicateat any given temperature.Five oharges were prepared eaoh oontaining equal-3-Th~se, were placed in muffle at a tenperature of about86~C. The tomperature was then raise~ and at 900C:the(\~e.. ~first charge was removed. Afte! each succeeding\reise )..in te!'1peratnre of 50.G) a charge was rer.1oved and poured •.An a.ssay of the resulting sla.gs for 8i02 eave the figu.resshown in Table :11.Table III., Ji'teMP. c0grarJsl grams. si~ i- ISlag grams 3i02IS102 pTa::;CO. ca1 e sample SiO" int",~ I deE ree : Rtn grams samplei Itr1~ I ,.• I10 f 10 900e. 5.82 2.98 518i11 catej i..!110I• I10 Tf 950(; . 2.62 1.57 60~II !1 10G1,0 on I 900e- 3.74 2.46 65~ ~ ti---- i . ,~10 I 10 n i 1050·0·1 1.52 1.02 67! ! f,I10 J 10 t n ! 11OO~JI 1.72 1.20 70i ! j !!~JThe results on the first problem show; that theMore acid the slag the mote fusible it is and that asodiuM silioate containing 1 part 8i02 by weight totwo parts of Na2COZ is preferable; that the additionof other bases lowers considerabl, the melting pointof the silicate; that the addition of PbO and FeD makes-4-tho sodium silicate more easily fusible even in the casewhere the addition of these substances ~akes the slag:.''1ore basic; tha.t the addition of CaO or of A1203 Makesthe slag !:lore difficult to fuse; that sodium silicates,alone are viscous at assay temperatures.In the second experiment I attempted to deter-:'Jine the a~'T}ount of Ag held in the filtrate froM a KONsolution after the Ag had been preaipitated by each ofthree different methods. Four cyanide solutions wereused containing at the start free KeN as follows:No.1, 0.05 ~; No.2,O.15 ~; No.3, 0.50 %; No.4, 0.50 %.To these solutions was added AgNOs solution until TIo.l.contained 0.86 Oz. Ag, No.2 y 28.5 oz. Ag, No.3, 1.6oz. Ag,No.4, 42.7 oz. Ag per ton of solution. The addition ofthe ailver t of course, greatly reduced -the an!'')unt of freecyanide ,present by forming Z Ag (Cn)2 •The Methods of precipitating the Ag from thesolution) I will designate as At Band C.(A) Take 1 A.T. of solutionAdd CuS04 as long as precipitate forms.Filter.Transfer filtrate to lead boat.EvaporateCnpel the boat and residue.-5-(B) Take 1 A.T. of solutionAdd CuS04 until precipitate just startsto form.Add small amount of H2S04Filter, etc., as in (A).(C) Ta,ke 1 A.. T. of soluti onAdd CUS04 as in (A)Add excess of H2S04Filter, etc., as in preceeding cases.All three methods were tried on each of the foursolutions and the results are shown in Table IV.Table IV.0.000.080.00Ag infiltrateOZ. per ton.ABr m::~~dI0.86assay ofsolution OZ,Ag per ton0.051<1 "'7"C" .) e~ "", lDsolution be-fore adding IAg1104 I~---T!!I2 20I, .I B i 1.400.15 28.50 C I 2.90I+!0.080.000.50 I 1.60 0.12.. ,.I 3.80'B 0.00,J c-0.50 ~ 42.70 j 6.30-6-Fro~ the results obtained, it would appear thatthe r'1ethod designated as "Bn gave the best resul ts as ineach case the 10S8 of Lg due to an iml..erfect precipitationwas less in this method than in either of the others.In the case where a large excess of acid is usedit may be that a considerable amount of free cyanogen isregenerated which may redissolve a part of the stIver.In the case of the solution low in free oyanide, but highin silver,none of the sche~es mentioned gave good precipita-tion.The third problem investigated dealt with thenail assay and in this I attempted to find the amount ofAg held up -by a possible formation of Matte in fusing asUlphide ore. For this purpose a IJure p::ri te was groundthru 10 mesh. A solution of ~gTI03 was added sufficiento.~("i\'ft-to give the ore a oontent of150 oz. ~g per ton andJ 8fterdrying, the ore was gronnd thru 100 Plash. Four differentcharges were used oonsisting of the following mixtures:No. I - 15 grams soda- 80 grams PbO- 24 D"rams ::EcnOr7l::.> {)- ~~ A.T. ore- 10 erama borax glass-'7-No.2 - 15 grams soda- 40 grarlS PbO- 24 gra:Yls- t A.T. ore- 10 graP1S borax elass:NO.3-25 grans soda- 20 grams PbO- 3 grams argol- 10 grams borax glass-I R.T. ere"2No.4 - 25 grams soda-20 grams PbO-3 grams argo1.A. A.T. Qre~-10 gra.ms bora.x glass- 5 nailsTIo rlatte was formed in the nail method. (~o 4-")'~"'~"' ..The assay of the other Mattes for Ag is shown in thef'ollowing table.-8-charge, weightused 10f :'latte Ag inrlatte Ag inmatte perton ore usedaSRB.yraworeoz perton re-covery01 emfttef 1 4.1 gramsi O.04mg~s 0.08 oz. 57.20 oz 57.10 0.086.2!) 3.4 "0.10 tf0.04 n0.20 IT0.08 n56.80 O.~O57.06 O. D8J 0 :-)2gra,rl'} q • t:J 1!lgm. I.. I0.18" I\ iIT: II 0.22 n iI II,n 0.22 TT4.0~ 7.6,8.87.26.6n ~ 0.06 TT 0.12 n0.36 TT0.44 !T0.44 Tf· i157.20oz57.0256.7256.7456.5056.46o. 2o.a4O. p6O. 4o. ~40.960.84J1 3-j; ~ 11.0 Bms~ 0.42mgM. 0.84 oz 56.20! 12.2 n I0.48 n 0.96 n 57.20 oz 56.08, 16.3 n I0.58 n 1.16 n 53.20 1.16., 12.6 _ff_...LJ_O_._5....;2_fT_...v...-_l_._0_4_1_'_-:.- ---J&--_5_4_._4_0-.L-_l_.~_t__4-.rr 4 no matte forr'ledT.The high litharge or niter assay should, ofoourse, show no ~a+.te provided the amount of oxidizingmaterial is enongh, and suffictent time is allowed forthe reducing r-1aterial to be burnett. It is of interes.t tonote that altho the amount of matte formed when th£nailsare omitted at the sane time that the oharge laaks oxidiz-ing material is large ~!et it does not carry a large percent-age of the values, a result to be expected, of oourse. whenit is remembered that there ts thrown down at the same time-9-at least 20 grams of lead. ~inen the behavior of thepyrite, on being heated when oxidizing condttions arelaclring, is considered t the quest ion arises, H\7hy is itthat the presence of metallic iron is necessary to enablethe soda to dissolve the iron matte forrned. Tf It certainlyis true that p~rite heated to the full temperature of theassay furnace must give a matte, provided that a matteforms at all, which is approxi~ately FeS and it seems thatthis must also be the matte formed when the ~etal1ic irondecomposes the pyrite. There is here a field for con-siderable research and reasoning.I IT D E XPage.A.ssayOf 3i02 in sodium silicate - - - - - - - - - - ~Of Filtrate from Ken solution - - - - - - - -- ~Nail, Advantages of, - - - - - - - - - - - - - 7ChargesFor nail assay, - - -------'6For high 1 i tharge - - - - - - - - - _.- - 7For Problem III. - - - - - - - - - - - - - - -- ~Copper Sulphate,Use in preoipitating Yilig~N2 - - - - - - - - - ~Fulton, C.H.Referenaes regarding silicate degree from - - - J~lsion TemperatureOf sodiuM silicate - - - - - - - - - - - - - - 2Of sodium basic silicates - - - - - - - - - - - 3FiltrateFrom KOn solution -How treated - - - - - - - - - -(0- - -- "Assay of - - - - - - - - - - - - - - - - - - - ~H2 S04Use in preoipitating KAgCN2Ken solutionsStrength of - - - - - - - - - - - - - - - - -- &)Ag due toAg held in,rnatt~,~ - - - - - - - - - - - - - 9Cause of formation,- -Amount Ag in MBtte,-Assay of 1- - - - - - - - - - - - - - -Methods- - - C)- - - :3- - - '3Used in deter~ining Ag in matte,- - - - - - - - - gUsed in determining Ag in filtrate fromKen solution,- - - - - - - - - -~PrecipitationOf,KAgCII2 froM KOn solution,- - - - - - - - - - - (0SlagAssay of sodium silicate slags,- - - - - - - - - - 2Sodium silicateTemperature pf ~lsion, - - - - - - - - 2-Appearance after fusi.on, - - - - - - - - - - -2Appearance after cooling, - - - - - - - - - - - - 2Silicate DegreeEffect on fusibility of assay slags, - - - - - -- IVarious silioate degrees, - - -Fulton, C. H. on, - - - - - - - - - -- - - 2.- - - - J

Some assay problems

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Some assay problems

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