The report presents a technological scheme of complex processing of man-made waste of phosphorus production - slag to produce highly dispersed silicon dioxide and a rare-earth metal concentrate. The technological parameters of each operation of the technology are chosen. Recovery of rare-earth metals from phosphorus slags during various operations was, %: leaching – 95.0; extraction - 90.2; stripping on the average ~ 93.2; the production of ∑ REM oxide concentrate is 93.9. The composition of some batches of "white soot" obtained during processing of the technological scheme is shown.
Keywords: Phosphorus slag, Leaching, Extraction, Stripping, Rare-earth metals, White soot, concentrate of Σ REM oxid

Abisheva, Z.S.

Bochevskaya, E.G.

Karshigina, Z.B.

Sargelova, E.A.

Sharipova, A.S.

KnE Materials Science

English

The report presents a technological scheme of complex processing of man-made waste of phosphorus production - slag to produce highly dispersed silicon dioxide and a rare-earth metal concentrate. The technological parameters of each operation of the technology are chosen. Recovery of rare-earth metals from phosphorus slags during various operations was, %: leaching – 95.0; extraction - 90.2; stripping on the average ∼ 93.2; the production of ∑ REM oxide concentrate is 93.9. The composition of some batches of "white soot" obtained during processing of the technological scheme is shown

Bochevskaya, E. G.

Karshigina, Z. B.

Abisheva, Z. S.

Sargelova, E. A.

Sharipova, A. S.

Institutional repository of Ural Federal University named after the first President of Russia B.N.Yeltsin

Comprehensive Processing Technology of Slags of Phosphorus Industry to Produce Precipitated Silica and Rare-Earth Concentrate

KnE Publishing Platform

 KnE Materials ScienceTochnogen Conference ProceedingsInternational Conference with Elements of School for Young Scientistson Recycling and Utilization of Technogenic Formations (2017)Conference PaperComprehensive Processing Technology ofSlags of Phosphorus Industry To ProducePrecipitated Silica and Rare-Earth ConcentrateE. G. Bochevskaya1, Z. B. Karshigina1, Z. S. Abisheva2,E. A. Sargelova1, and A.S. Sharipova11JSC ”Institute of Metallurgy and Beneficiation”, Almaty, Kazakhstan2NJSC ”Kazakh National Research Technical University them. K. I. Satpayev”, Almaty, KazakhstanAbstractThe report presents a technological scheme of complex processing of man-madewaste of phosphorus production - slag to produce highly dispersed silicon dioxideand a rare-earth metal concentrate. The technological parameters of each operationof the technology are chosen. Recovery of rare-earth metals from phosphorus slagsduring various operations was, %: leaching – 95.0; extraction - 90.2; stripping on theaverage ∼ 93.2; the production of ∑ REM oxide concentrate is 93.9. The compositionof some batches of ”white soot” obtained during processing of the technologicalscheme is shown.Keywords: Phosphorus slag, Leaching, Extraction, Stripping, Rare-earth metals,White soot, concentrate of∑ REM oxide1. IntroductionMany studies have been devoted to the utilization of phosphorus slags. Most of themare targeted to processing phosphorus slags for use in building materials and productsmade of them: technologies have been developed for the production of granular slags,slag crushed stone, slag pumice, mineral wool, slag stone, cast and other buildingproducts and materials [1]. One of the applications of granular phosphorus slag is touse it to strengthen saline soils, as well as, to create strong and cheap structural layersof road toppings.However, in spite of large effort made to dispose phosphorus slag, most of it stillremains in dumps, thus worsening the ecological situation in the Southern regions ofKazakhstan. One of the reasons for the inefficient use of slags today is a low cost ofproducts prepared from it, thus making the processing of slags economically unprof-itable. Therefore, it is important to find ways to process phosphorus slag to obtain highvalue-added products strongly demanded by industry.The preparation of precipitated highly dispersed silica from phosphorus slag is thedirection of high priority today.How to cite this article: E. G. Bochevskaya, Z. B. Karshigina, Z. S. Abisheva, E. A. Sargelova, and A.S. Sharipova, (2017) “Comprehensive ProcessingTechnology of Slags of Phosphorus Industry To Produce Precipitated Silica and Rare-Earth Concentrate,” Detaliedconferencename, journalname,116–120. DOI 10.18502/kms.v2i2.956Page 116Corresponding Author: E. G.Bochevskaya; email:elena_bochevskaya@mail.ruReceived: 6 June 2017Accepted: 9 July 2017Published: 24 August 2017Publishing services providedby Knowledge EE. G. Bochevskaya etal. This article is distributedunder the terms of theCreative CommonsAttribution License, whichpermits unrestricted use andredistribution provided thatthe original author andsource are credited.Selection and Selection andPeer-review under theresponsibility of theTechnogen ConferenceCommittee. KnE Materials Science Tochnogen Conference ProceedingsRecently an increase in demand for amorphous nanodisperse silica is observed. Inaddition to its traditional use as additives in rubber, plastics, paper, for making glues,liquid glass, ceramics, adsorbents, etc., the consumption of nanodispersed chemicallypure amorphous silica in high-tech industries, such as the production of light guides,semiconductor silicon, newphotomaterials, ceramic oxides, highly dispersed abrasives,catalysts, sorbents for chromatography, for the determination of various inorganic andorganic compounds as with the help of analytical instruments (spectrophotometers,reflectometers), and with the use of indicator tubes, drugs and cosmetics.Phosphorus slag with the content of SiO2 35-42 % can serve as a source for pro-duction of precipitated silica [2, 3]. Developments for obtaining mineral fillers fromwastes of the phosphoric industry were carried out at JSC ”Institute of Metallurgy andBeneficiation” in collaboration with specialists from phosphorus plants [4].The recovery of rare-earth metals (REM) along with the production of precipitatedsilicon dioxide from slag is also of great interest.2. Results and DiscussionThe object of research was slag of phosphorus production of Zhambyl branch of“Kazphosphate” Ltd. (NDPP) with the following composition, % (wt.): 36.9 SiO2; 43.2CaO; 5.2 Al2O3; 2.0 P2O5; 1.60 Fe2O3; 0.057 Ba; 2.4 MgO; 0.14 TiO2, Sr 0.16 and so on;∑∑ KУЬ – 536.48 g/t.We report here a flow diagram of comprehensive phosphorus slag processing toobtain precipitated silica (”white soot”) and RE concentrate (Figure 1).The technology includes the following operations:• First stage of slag leaching with the solution of nitric acid;• REM-containing solution extraction with tributyl phosphate (TBP)• Stripping of the REM with water;• Sedimentation of∑ REM salts with the solution of oxalic acid,• Calcination of the precipitate to obtain a concentrate of∑ REM oxides• Second stage of leaching of the silicon-containing cake to obtain ”white soot”Regime parameters of the technology of comprehensive slag processing:1. The first stage of leaching is carried out using 7.5 mol/dm3 of nitric acid at tem-perature of – 60 ∘C and during 1 h under vigorous stirring with a rotating stirrer.To prevent an active transition of silica to a gel state, the leaching of phospho-rus slag was performed under conditions that lower the decomposition rate ofDOI 10.18502/kms.v2i2.956 Page 117 KnE Materials Science Tochnogen Conference ProceedingsContent, [% (wt.)] pH of aqueousextractSpecific surfacearea, [m2/g]SiO2 Al2O3 CaO MgO Fe2O3 Na2OState standard (18307 – 78)87.0 0.1 0.8 0.17 1.1 8.0-9.5 120±20”White soot”87.0 0.09 0.6 0.14 0.05 9.2 14487.0 0.09 0.4 0.16 0.05 9.4 19688.5 0.10 0.7 0.14 0.06 9.4 160T 1: Physicochemical parameters of ”white soot”.calcium silicate. To meet these conditions, leaching is preceded by a preliminarypreparation, i.e. the repulping of phosphorus slag that consists of mixing of theslag with water at ratio S : L = 1:1 with simultaneous heating of the pulp to apredetermined temperature. The pretreatment temperature of phosphorus slagin water was kept at 10 ∘C below the leaching temperature. After that the con-centrated nitric acid was gradually added to the pulp under intensive stirring. Inthe first 0.5 h about 25 % of the total amount of nitric acid introduced, in the next0.5 h - the rest of it. The pulp was then heated to the desired temperature andleached under stirring for 1 h. The S: L ratio was 1: 2.6 after taking into accountwater introduced for repulpation.2. Extraction of the solution after leaching of slag containing 196 mg/dm3 ∑REM,and g/dm3: 123.93 Ca, 9.79 Al and 2.94 Fe was carried out under the followingconditions: extractant, % (v/v): 50 TBP, 50 purified kerosene, the ratio of O:A =1 : 6, the contact time of the phases is 5 min, phase separation time is 5 min,temperature is 25±5 ∘C, the number of stages is 3.3. The stripping was carried out with water at ratio of O: A = 6: 1, temperatureof 25±5 ∘C and a phase contact time of 5 min, the number of steps was 1. Theconcentration of ∑REM in re-extracts averaged ∼ 5.9 - 6.0 g/dm3, the recoveryfrom the saturated organic phase was ∼ 92 – 94 %, respectively.4. Deposition of REM salts was carried out with 2 mol/dm3 solution of oxalic acid,washing the precipitate with hot water, drying and calcining it at 900 ∘C for 2 h toobtain a concentrate of∑ REM oxide.5. Second stage of leaching of the silicon-containing cake obtained from the firststage, was done with 1.6 mol/dm3 nitric acid solution, then washing of the pre-cipitated silica to reach pH 6 -6.5, drying the precipitate at 300 ∘C, abrasion of the”white soot” on the sieve 0.14.DOI 10.18502/kms.v2i2.956 Page 118 KnE Materials Science Tochnogen Conference Proceedings HNO3 solution REMs-containing solution Poor organic Re-extract Extract Raffinate For the production construction materials and Si-containing cake Wash water GRINDING Phosphorus slag REPULPING, LEACHING (FIRST STAGE) FILTRATION DRYING Wash water LEACHING  (SECOND STAGE) FILTRATION Cake WASHING “White soot” HNO3 solution   H2O EXTRACTION STRIPPING  H2O REMs concentrate Cake REMs-containing solution REGENERATION REMs OXALATES PRECIPITATION  TBP WASHING FILTRATION Solution Precipitate CALCINATION Wash water Precipitate H2O TBP С2H2O4 solution Figure 1: Technological scheme for processing phosphorus slag to obtain precipitated silicon dioxide andREM concentrate.Recovery of ΣREM from phosphorus slags during various operations was, %: leach-ing – 95.0; extraction - 90.2; stripping on the average ∼ 93.2; the production of∑ REMoxide concentrate is 93.9.Table 1 shows the composition of some batches of ”white soot” obtained during theprocessing of the technological scheme.DOI 10.18502/kms.v2i2.956 Page 119 KnE Materials Science Tochnogen Conference ProceedingsThe appearance and color of ”white soot” precipitates are identical to each other andmeet the requirements of State standard (18307 – 78). The content of silicon dioxidein ”white soot” varies from 87.0 to 88.5 %. The specific surface area of the obtainedbatches of precipitated silica was in the range of 144 - 196 m2/g. The spread of thevalues is due to the fact that the deposits of ”white soot” were dried in a cabinet attemperature of 300 ∘C. In production conditions, drying is generally carried out in spraydryers (fluidized bed furnaces) at a temperature of 750 ∘C. The throughout extractionrate of the silicon product and the REM oxides into the concentrate from their initialcontent in the slags was ∼ 98.0 and 75.0 %, respectively.3. SummaryThe developed technology of comprehensive phosphorus slag processing to obtainprecipitated silicon dioxide powders and rare-earth concentrate can solve the problemof complex processing of phosphorus raw materials and import substitution in Kaza-khstan.References[1] X. J. Jiang, Y. Yun, and Z. H. Hu, “Development of non-autoclaved aerated concreteby alkali activated phosphorus slag,” Advanced Materials Research, vol. 250-253,pp. 1147–1152, 2011.[2] Y. Su, G. Li, and J. Xia, “Experimental study of leaching yellow phosphorus slag byphosphoric acid,” Journal of Solid Waste Technology and Management, vol. 36, no.1, pp. 39–43, 2010.[3] G. Li, H. Lin, Y. Ma, and Y. Su, “Experimental study of purifying precipitated silicaproduced from yellow phosphorus slag,” Advanced Materials Research, vol. 455-456, pp. 503–506, 2012.[4] Z. Karshigina, Z. Abisheva, Y. Bochevskaya, A. Akcil, and E. Sargelova, “Recovery ofrare earth metals and precipitated silicon dioxide from phosphorus slag,” MineralsEngineering, vol. 77, article no. 4614, pp. 159–166, 2015.DOI 10.18502/kms.v2i2.956 Page 120

Comprehensive Processing Technology Of Slags Of Phosphorus Industry To Produce Precipitated Silica And Rare-Earth Concentrate

&lt;p class="TTPSectionHeading"&gt;The report presents a technological scheme of complex processing of man-made waste of phosphorus production - slag to produce highly dispersed silicon dioxide and a rare-earth metal concentrate. The technological parameters of each operation of the technology are chosen. Recovery of &lt;span&gt;rare-earth metals&lt;/span&gt; from phosphorus slags during various operations was, %: leaching – 95.0; extraction - 90.2; stripping on the average ~ 93.2; the production of ∑ REM oxide concentrate is 93.9. The composition of some batches of "white soot" obtained during processing of the technological scheme is shown.&lt;/p&gt;</jats:p

Comprehensive Processing Technology Of Slags Of Phosphorus Industry To Produce Precipitated Silica And Rare-Earth Concentrate

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