Table 3. FIC Values for HEDP, AEDP, ATMP, and New Hydroxybisphosphonate SIs for Calcite Scale^b.

	calcite scale
	first blank	first scale test		second scale test		second blank
SI (1000 ppm)c	time (min)	concn (ppm)	time (min)	concn (ppm)	time (min)	time (min)
HEDP	12	1	35	1	36	13
AEDP(28)	6	20	22	20	21	8
ATMP(33)	11	20	26	20	26	12
SI-1	17	2	26	2	26	17
SI-2	18	2	30	2	34	18
SI-3	12	2	19	2	19	12
SI-4	16	10	4	10	4	14
SI-5	16	10	40	10	35	14
SI-6	16	2	26	2	28	17
SI-7	15	2	18	2	19	14
SI-1a	17	2	31	2	32	19
SI-2a	14	10	24	10	20	14
SI-3a	16	1	42	1	43	15
SI-4a	14	10	56	10	56	15
SI-5a	14	20	46	20	50	14
SI-6a	12	5	10	5	12	13
SI-7a	15	5	25	5	30	16

^aAll synthesized SIs (SI-1–SI-7) were tested for calcite scale after thermal aging at 130 °C for 7 days.

^bThe accuracy for all numerical values was ±5 min.

^cThe pH of all SIs was adjusted in the range of 4–6 in 1000 ppm aqueous solution.