1、BRITISH STANDARD BS 6857:1987 ISO 4620:1986 Specification for Cadmium pigments for paints Cadmium pigments Specification and methods of test UDC 667.622.11:661.848BS6857:1987 This British Standard, having been prepared under the directionof the Pigments, Paintsand Varnishes StandardsCommittee, was p
2、ublished under the authority ofthe Board of BSI and comes intoeffect on 31July1987 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference PVC/1 Draft for comment 80/53927 DC ISBN 0 580 16016 5 Committees responsible for this British Standard The preparation
3、 of this British Standard was entrusted by the Pigments, Paints and Varnishes Standards Committee (PVC/-) to Technical Committee PVC/1 upon which the following bodies were represented: Aluminium Powder and Paste Association British Colour Makers Association British Precast Concrete Federation Ltd. C
4、ement Makers Federation Chemical Industries Association Oil and Colour Chemists Association Paintmakers Association of Great Britain Ltd. Red Lead and Litharge Manufacturers Association Titanium Pigment Manufacturers Technical Committee Amendments issued since publication Amd. No. Date of issue Comm
5、entsBS6857:1987 BSI 12-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope and field of application 1 2 References 1 3 Definition 1 4 Classification 2 5 Required characteristics and their tolerances 2 6 Sampling 2 7 Determination of total cadmium and zinc cont
6、ents 2 8 Determination of selenium content 4 9 Determination of sulfur content 5 10 Calculation of the total content of cadmium, zinc, selenium and sulfur 6 11 Preparation of the hydrochloric acid extract 6 12 Determination of “soluble” antimony content 6 13 Determination of “soluble” arsenic conten
7、t 6 14 Determination of “soluble” barium content 6 15 Determination of “soluble” cadmium content 6 16 Determination of “soluble” chromium content 8 17 Determination of “soluble” lead content 8 18 Determination of “soluble” mercury content 8 19 Determination of “soluble” selenium content 8 20 Determi
8、nation of “soluble” zinc content 8 21 Test report 10 Table 1 Essential requirements 3 Table 2 Conditional requirements 3 Table 3 Standard matching solutions 9 Publications referred to Inside back coverBS6857:1987 ii BSI 12-1999 National foreword This British Standard has been prepared under the dire
9、ction of the Pigments, Paints and Varnishes Standards Committee. It is identical with ISO4620:1986 “Cadmium pigments Specifications and methods of test”, published by the International Organization for Standardization (ISO). It has been assumed in the drafting of this standard that it will be used a
10、nd applied by those who are appropriately qualified and experienced. The substances and procedures described may be injurious to health if adequate precautions are not taken. This standard refers only to its technical suitability and does not absolve the user from statutory obligations relating to h
11、ealth and safety. Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially
12、to the following. The comma has been used as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. The symbol “l” has been used to denote litre (and in its submultiples). In British Standards it is current practice to use the symbol
13、“L” and to use the spelling “sulphur”, etc.,instead of “sulfur”, etc. Wherever the words “International Standard” appear, referring to this standard, they should be read as “British Standard”. Cross-references International Standards Corresponding British Standards BS 3483 Methods for testing pigmen
14、ts for paints ISO 787-1:1982 Part A1:1983 Comparison of colour (Identical) ISO 787-2:1981 Part B6:1982 Determination of matter volatile at105 C (Identical) ISO 787-5:1980 Part B7:1974 Determination of oil absorption value (Identical) ISO 787-7:1981 Part B3:1974 Determination of residue on sieve (wat
15、er method, using a manual procedure) (Identical) ISO 787-8:1979 Part C2:1980 Determination of matter soluble in water (cold extraction method) (Identical) ISO 787-9:1981 Part C4:1982 Determination of pH value of an aqueous suspension (Identical) ISO 787-16:1986 Part A4:1974 Comparison of relative ti
16、nting strength (or equivalent colouring value) and colour on reduction in linseed stand oil using the automatic muller (Technically equivalent) ISO 787-20:1975 Part B5:1974 Comparison of ease of dispersion (oscillatory shaking method) (Technically equivalent) ISO 787-21:1979 Part C8:1980 Comparison
17、of heat stability (Identical) ISO 842:1984 BS 4726:1986 Methods for sampling raw materials for paints and varnishes (Identical)BS6857:1987 BSI 12-1999 iii The Technical Committee has reviewed the provisions of the following International Standards, to which reference is made in the text, and has dec
18、ided that they are acceptable for use in conjunction with this British Standard. Related British Standards are given in parentheses. Pending publication of ISO3856-8 and ISO3856-9 any suitable methods for the determination of soluble selenium and soluble arsenic should be used in combination with BS
19、3900-B5. It is intended to implement ISO3856-8 and ISO3856-9 as British Standards when they are published. Additional information. In order to carry out some of the tests described in this standard it is necessary for a reference sample to be supplied or agreed by the parties concerned (seeclause5 a
20、ndTable 2). NOTEIn clause2, in the titles of ISO3856-2 and ISO 3856-6, “spetrophotometric” and “spetrometric” should read “spectrophotometric” and “spectrometric” respectively. In the note at the beginning of clause7, line5, “interesed” should read “interested”. International Standards Corresponding
21、 British Standards ISO 1042:1983 BS 1792:1982 Specification for one-mark volumetric flasks (Identical) BS 3900 Methods of test for paints ISO 3856-1:1984 Part B6:1986 Determination of “soluble” lead content (Identical) ISO 3856-2:1984 Part B7:1986 Determination of “soluble” antimony content (Identic
22、al) ISO 3856-3:1984 Part B8:1986 Determination of “soluble” barium content (Identical) ISO 3856-4:1984 Part B9:1986 Determination of “soluble” cadmium content (Identical) ISO 3856-6:1984 Part B11:1986 Determination of total chromium content of liquid matter (Identical) ISO 3856-7:1984 Part B12:1986
23、Determination of “soluble” mercury content (Identical) ISO 4793:1980 BS 1752:1983 Specification for laboratory sintered or fritted filters including porosity grading (Identical) BS 3900 Methods of test for paints ISO 6713:1984 Part B5:1986 Preparation of acid extracts from liquid paints or coating p
24、owders (Identical) ISO 385-1:1984 (BS 846:1985. Specification for burettes) ISO 648:1977 (BS 1583:1986. Specification for one-mark pipettes) ISO 3696 a (BS 3978:1966. Specification for water for laboratory use) ISO 3856-8 a (No British Standard) ISO 3856-9 a BS 4404:1968. Method for the determinatio
25、n of arsenic (silver diethyldithiocarbamate procedure) a In preparation.BS6857:1987 iv BSI 12-1999 A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard d
26、oes not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages1to 10, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. Th
27、is will be indicated in the amendment table on the inside front cover.BS6857:1987 BSI 12-1999 1 1 Scope and field of application This International Standard specifies the requirements and the corresponding methods of test for cadmium pigments suitable for general use. 2 References ISO 385-1, Laborat
28、ory glassware Burettes Part1: General requirements. ISO 648, Laboratory glassware One-mark pipettes. ISO 787, General methods of test for pigments and extenders Part 1: Comparison of colour of pigments; Part 2: Determination of matter volatile at105 C; Part 5: Determination of oil absorption value;
29、Part 7: Determination of residue on sieve Water method Manual procedure; Part 8: Determination of matter soluble in water Cold extraction method; Part 9: Determination of pH value of an aqueous suspension; Part 16: Determination of relative tinting strength (or equivalent colouring value) and colour
30、 on reduction of coloured pigments Visual comparison method; Part 20: Comparison of ease of dispersion (oscillatory shaking method); Part 21: Comparison of heat stability of pigments using a stoving medium. ISO 842, Raw materials for paints and varnishes Sampling. ISO 1042, Laboratory glassware One-
31、mark volumetric flasks. ISO 3696, Water for laboratory use Specifications. 1) ISO 3856, Paints and varnishes Determination of “soluble” metal content Part 1: Determination of lead content Flame atomic absorption spectrometric method and dithizone spectrophotometric method; Part 2: Determination of a
32、ntimony content Flame atomic absorption spectrometric method and RhodamineB spectrophotometric method; Part 3: Determination of barium content Flame atomic emission spectrometric method; Part 4: Determination of cadmium content Flame atomic absorption spectrometric method and polarographic method; P
33、art 6: Determination of total chromium content of the liquid portion of the paint Flame atomic absorption spectrometric method; Part 7: Determination of mercury content of the pigment portion of the paint and of the liquid portion of water-dilutable paints Flameless atomic absorption spectrometric m
34、ethod; Part 8: Determination of selenium content Flame atomic absorption spectrometric method and X-ray fluorescence method; 2) Part 9: Determination of arsenic content Atomic absorption and silver diethyldithiocarbamate spectrometric methods. 1) ISO 4793, Laboratory sintered (fritted) filters Poros
35、ity grading, classification and designation. ISO 6713, Paints and varnishes Preparation of acid extracts from paints in liquid or powder form. 3 Definition cadmium pigment an inorganic coloured pigment consisting predominantly of cadmium sulfide or of mixed crystals of cadmium sulfide and cadmium se
36、lenide, in which the cadmium may be partially replaced by zinc NOTE 1To adjust the relative tinting strength and/or to obtain certain application properties, cadmium pigments may contain colourless additives. NOTE 2Cadmium pigments are characterized by a very low solubility in water and diluted acid
37、s and by a very high heat stability. NOTE 3Yellow cadmium pigments consist mainly of mixed crystals of cadmium sulfide and zinc sulfide (Pigment yellowNo.37, part2, ref.77199) 3)or of cadmium sulfide (Pigment orange No.20, part2, ref.77199). 3) Orange to maroon cadmium pigments consist mainly of mix
38、ed crystals of cadmium sulfide and cadmium selenide (Pigment redNo.108, part2, ref77202 3) . 1) At present at the stage of draft. 2) In preparation. 3) Classification according to the Colour Index. The Colour Index is published by the Society of Dyers and Colourists, Bradford, England and the Americ
39、an Association of Textile Chemists and Colorists, Lowell, Mass. (USA), revised edition1971.BS6857:1987 2 BSI 12-1999 4 Classification This International Standard specifies the following three types of pigment, which shall be free from organic materials, other coloured inorganic pigments and brighten
40、ing agents: Type 1: Cadmium pigments, concentrated. These pigments contain not more than30% (m/m) of extenders to adjust their relative tinting strength. Type 2: Cadmium pigments, extended. These pigments contain not more than70% (m/m) of extenders to facilitate processing. Type 3: Cadmium pigments,
41、 unextended. These are essentially pure and do not contain any extenders. NOTEType1 and type2 pigments are generally suitable for use in paints, plastics, rubber, etc.Type3 pigments are mainly suitable for use in ceramics. 5 Required characteristics and their tolerances 5.1 For cadmium pigments comp
42、lying with this International Standard, the essential requirements are specified inTable 1 and the conditional requirements are referred to inTable 2. For the conditional requirements to be specified, prior agreement between the interested parties is necessary. 5.2 The agreed reference pigment, whic
43、h is referred to inTable 2, shall conform with the requirements specified inTable 1. 6 Sampling Take a representative sample of the product to be tested as described inISO842. 7 Determination of total cadmium and zinc contents NOTEThe method given in this clause allows the separate determination of
44、the alkali earth metals present. However, it should be used only for cadmium pigments with a zinc content greater than5%. For pigments with lower zinc contents, a suitable atomic absorption spectrometric method should be agreed between the interesed parties. 7.1 Principle Dissolution of a test porti
45、on in hydrochloric acid and nitric acid. After neutralization, addition of potassium cyanide and titration of the alkali earth metals with EDTA solution. Addition of formaldehyde solution to destroy the cadmium and zinc cyanide complexes. Titration of the sum of cadmium and zinc ions with EDTA solut
46、ion. Destruction of the cadmium-EDTA complex in the titrated solution with sodium diethyldithiocarbamate and precipitation of the cadmium with ammonia solution. Back-titration of the excess of EDTA corresponding to the cadmium, with magnesium sulfate solution. 7.2 Reagents During the analysis, use o
47、nly reagents of recognized analytical grade and only water of at least grade3 purity according to ISO3696. WARNING Use the reagents in accordance with the appropriate health and safety regulations. 7.2.1 Hydrochloric acid, approximately37% (m/m), approximately1,18g/ml. 7.2.2 Hydrochloric acid, dilut
48、ed, c(HCl) approximately0,1mol/l. 7.2.3 Nitric acid, approximately65% (m/m), approximately1,40g/ml. 7.2.4 Sodium hydroxide, 10% (m/m) solution. 7.2.5 Ammonia solution, approximately25% (m/m), approximately0,91g/ml. 7.2.6 EDTA, standard volumetric solution, c(EDTA)=0,1mol/l. Dissolve37,225g of disodi
49、um ethylenediamine-tetraacetate dihydrate (EDTA disodium salt) in water in a1000ml one-mark volumetric flask, dilute to the mark and mix well.BS6857:1987 BSI 12-1999 3 Table 1 Essential requirements Table 2 Conditional requirements Characteristic Requirement Test method Total (Cd + Zn + Se + S) type 1, % (m/m) min. 70 type 2, % (m/m) min. 30 Clause 10 type 3, % (m/m) min. 98 Matter volatile at 105 C % (m/m) max. 0,5 ISO 787-2 Matter soluble in water (cold extrac
